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. 2025 Aug 27;10(35):40557–40566. doi: 10.1021/acsomega.5c06250

Boosting Photoelectrochemical Catalytic Ability of Bismuth Vanadate toward Water Oxidation via Synergistic Surface Defect Engineering and MXene-Assisted Charge Transport

Tsai-Mu Cheng †,‡,§,*, Yi-Ru Wang ∥, Yu-Hsuan Chiu ∥, Chutima Kongvarhodom ⊥, Muhammad Saukani #, Sibidou Yougbaré ∇, Hung-Ming Chen ○, Lu-Yin Lin ∥,*
PMCID: PMC12423830  PMID: 40949190

Abstract

Bismuth vanadate (BiVO4) is regarded as a promising photoanode material for solar-driven photoelectrochemical (PEC) water oxidation, due to its visible-light absorption and favorable band edge positions. However, the practical application is hindered by limited charge carrier mobility and significant surface recombination. In this study, a dual-modification strategy is applied by combining alkaline etching and MXene integration to enhance surface reactivity and charge transport properties of BiVO4. Alkaline etching introduces structural defects and active sites on BiVO4 surface, which promote hole accumulation and facilitate interfacial redox reactions. Meanwhile, incorporating MXene forms a conductive interface that accelerates hole extraction and suppresses recombination. Although alkaline etching slightly reduces light absorption due to morphological restructuring, the subsequent MXene addition recovers and enhances photon harvesting. In the absence of hole scavengers, the pristine BiVO4 electrode achieves a photocurrent density of 4.65 mA/cm2 at 1.23 V vs RHE at AM 1.5G, which increases to 5.13 mA/cm2 for alkaline-etched BiVO4 and further to 6.15 mA/cm2 for alkaline-etched BiVO4 coupled with MXene (MXene/E-BVO). Moreover, the MXene/E-BVO electrode retains 93.4% of its initial photocurrent after continuous illumination for 10,000 s. These results confirm the effectiveness of combining surface and interfacial engineering to improve PEC water splitting performance of BiVO4.

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1. Introduction

Hydrogen is regarded as a clean energy carrier due to its high energy density and its generation of water as a byproduct. − The transition from fossil fuel-based hydrogen production to renewable routes has gained significant momentum to global decarbonization goals and energy security demands. − Among hydrogen generation strategies, photoelectrochemical (PEC) water splitting presents an attractive approach by enabling direct solar-to-hydrogen energy conversion through a combination of semiconductor photoabsorption, charge carrier generation, and redox catalysis at the semiconductor/electrolyte interface. − This method has the potential to produce hydrogen sustainably without external electricity input to achieve sufficient efficiency and long-term operational stability. −

The photoanode in PEC water splitting plays a pivotal role by driving the oxygen evolution reaction (OER), which is kinetically sluggish and thermodynamically demanding. − Effective photoanode materials must simultaneously achieve strong absorption of photons, efficient separation and transport of photogenerated charge carriers, and rapid interfacial electron transfer. Among the candidates, bismuth vanadate (BiVO4) has emerged as a promising visible-light-driven photoanode due to its suitable bandgap (∼2.4–2.5 eV), and appropriate valence and conduction band positions for water oxidation. − Its monoclinic scheelite structure also favors carrier mobility in specific crystallographic directions. Nevertheless, the PEC performance of BiVO4 remains limited by poor charge transport within the bulk, rapid surface recombination of photogenerated holes, and insufficient catalytic activity toward OER. To overcome these limitations, several engineering strategies have been proposed, including elemental doping, ,,, cocatalyst deposition, , nanostructuring, − and heterojunction formation. ,, Surface modification, in particular, has gained considerable attention because many performance-limiting processes in BiVO4 occur at the semiconductor/electrolyte interface. − Among these, alkaline etching has proven effective in reconstructing the BiVO4 surface to expose additional active sites, increase surface area, and introduce oxygen vacancies or hydroxyl groups that facilitate hole trapping and water oxidation. Cheng et al. fabricated alkaline-etched BiVO4 by a hydrothermal method for catalyzing water oxidation. A photocurrent density of 2.38 mA/cm2 in Na2SO4 is obtained. Saada and co-workers reported electrodeposition of metal Bi in alkaline electrolyte for preparing photoelectrochemically active BiVO4 for catalyzing water splitting. Hsu et al. applied hydrothermal, soaking, and electrodeposition as different alkaline etching methods for conducting surface modifications on BiVO4 as the catalyst for water splitting with a photocurrent density of 2.38 mA/cm2 in a Na2SO4 solution. However, surface treatment alone often fails to address bulk conductivity and charge carrier transport, indicating the need for complementary strategies that target both surface and interfacial processes.

The integration of two-dimensional (2D) MXene materials such as Ti3C2T x offers a promising route for improving interfacial charge transport. MXenes exhibit high electrical conductivity, rich surface functionality (e.g., −OH, –F, –O groups), and good processability in aqueous media, making them attractive for forming intimate contact with semiconductor surfaces. ,− When used in photoelectrode systems, MXenes can act as hole extraction layers or conductive bridges to reduce series resistance, suppress electron/hole recombination, and accelerate interfacial charge transfer. Previous reports have demonstrated that MXene-functionalized BiVO4 composites exhibit improved PEC activity and photostability. Bai et al. constructed a hole transport layer on BiVO4 by doping MXene in Ferrihydrite, which presented a photocurrent density of 4.55 mA/cm2. Jahangir et al. synthesized Co3O4/MXene hybrids on BiVO4 as a dual-function material to catalyze water oxidation, and a photocurrent density of 5.05 mA/cm2 is obtained. Zhong and coauthors prepared metal–organic framework (MOF)/MXene/BiVO4 as a photocatalyst with a photocurrent density of 4.26 mA/cm2. However, most studies to date have applied MXene onto untreated or planar BiVO4 surfaces, potentially limiting the benefits of interfacial engineering due to insufficient surface area or poor coupling. The combination of alkaline etching and MXene integration has not been thoroughly explored as a synergistic approach to simultaneously enhance the surface activity and charge transfer capability of BiVO4 photoanodes. Alkaline etching introduces defect sites and increases roughness, providing favorable anchoring points for the conformal deposition of MXene layers. In turn, the ultrathin MXene layer can form intimate interfacial contact with the etched BiVO4 nanostructure, enabling rapid hole transport across the interface. This dual-modification strategy is expected to address both surface and interfacial bottlenecks in PEC water oxidation, leading to substantial improvements in photocurrent density and operational stability.

In this study, BiVO4 photoanodes were sequentially treated by alkaline etching and MXene incorporation to form a composite architecture. Morphological, structural, electronic and electrochemical properties of pristine BiVO4, alkaline-etched BiVO4 (E-BVO) and MXene coupled E-BVO (MXene/E-BVO) were analyzed to elucidate the effects of the dual treatments. The MXene/E-BVO photoanode exhibited a significantly enhanced photocurrent density of 6.15 mA/cm2 at 1.23 V vs RHE, which is much higher than the values obtained for pristine BiVO4 (4.65 mA/cm2) and E-BVO (5.13 mA/cm2) photoanodes. In addition, the MXene/E-BVO photoanode showed a low onset potential of 0.29 V vs RHE, a high carrier density of 4.12 × 1024 cm–3, and a reduced charge-transfer resistance of 116.6 Ω. Long-term durability tests confirmed 93.4% of the photocurrent retention after 10,000 s under continuous AM 1.5G illumination, highlighting the improved stability of the composite system. These results confirm that combining surface restructuring with conductive interfacial engineering offers a promising direction for advancing BiVO4-based photoanodes and PEC water-splitting technologies.

2. Experimental Section

2.1. Synthesis of Alkaline-Etched BiVO4 and That with MXene Incorporated Photoanodes

The pristine BiVO4 photoanode was prepared according to a previous work. Detailed experiments are shown in Supporting Information (SI). The alkaline-etched BiVO4 (E-BVO) photoanode is prepared by a hydrothermal method. A pristine BiVO4 photoanode is put into a liner which contains 0.1 M of NaOH solution (20 mL). The container is put into autoclave, which was then heated into 130 °C and maintained for 45 min. The product is washed by deionized water (DIW) after cooling down to obtain the E-BVO photoanode.

MXene powder (Ti3C2T x ) was synthesized by selectively etching Al from Ti3C2T x MAX phase using a modified HF-free LiF/HCl method. After etching, the MXene was washed repeatedly until the supernatant reached pH ∼ 6, and the resulting suspension was delaminated via ultrasonication in argon atmosphere. The concentration of the resulting MXene dispersion was adjusted to 1 mg/mL and stored under N2 to prevent oxidation. During MXene integration, E-BVO electrodes were immersed in the MXene solution in a Teflon-lined autoclave, allowing spontaneous coating driven by electrostatic attraction between negatively charged MXene nanosheets and the defect-rich BVO surface. The BVO and E-BVO photoanodes incorporated with MXene (MXene/BVO and MXene/E-BVO) are prepared by further conducting a hydrothermal method at 150 °C for 3 h with BVO and E-BVO photoanodes in the MXene solution. Scheme shows a process to fabricate BVO, E-BVO, MXene/BVO and MXene/E-BVO.

1. Process to Fabricate BVO, E-BVO, MXene/BVO and MXene/E-BVO.

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The temperature and duration of the hydrothermal process were optimized to balance the etching efficiency and preserve the rod-like BVO morphology. At 130 °C, sufficient surface reconstruction occurs without overdissolution, while at the subsequent 150 °C MXene treatment ensures intimate interfacial anchoring driven by thermal condensation and van der Waals interactions.

2.2. Fabrication of BVO Thin Film on FTO Substrate

The BVO photoanode was synthesized through a two-step method involving the electrodeposition of BiOI followed by a solution-based vanadium precursor conversion. Initially, BiOI was deposited on fluorine-doped tin oxide (FTO) glass using a three-electrode configuration, where Ag/AgCl and platinum wire served as the reference and counter electrodes, respectively. The deposition electrolyte was prepared by mixing two solutions. The first comprised 3.32 g of KI and Bi­(NO3)3·5H2O dissolved in deionized water, with the pH adjusted to 1.7 using nitric acid. The second solution consisted of 0.497 g of p-benzoquinone dissolved in 20 mL of absolute ethanol. Electrodeposition was performed at −0.1 V vs Ag/AgCl for 3 min. After deposition, a vanadium source solution was drop-cast onto the BiOI-coated substrate. This precursor solution contained 0.2 M vanadyl acetylacetonate and 0.02 M sodium tungstate dissolved in 5 mL of dimethyl sulfoxide (DMSO). The film was then annealed at 450 °C for 2 h using a ramp rate of 2 °C/min to form the final BVO structure. To remove surface residues such as V2O5, the annealed electrodes were rinsed with 1 M NaOH solution.

2.3. Characterization and Measurement Protocols

The surface morphology of the as-prepared photoanodes was examined by field-emission scanning electron microscopy (FE-SEM; Nova NanoSEM 230, FEI). Crystallographic features were analyzed using X-ray diffraction (XRD; X’Pert3 Powder, PANalytical), while elemental composition and chemical states were determined by X-ray photoelectron spectroscopy (XPS; VG ESCALAB 250, Al Kα source). Optical absorption properties and estimated band gaps were evaluated by UV–vis spectroscopy (JASCO V750). For electrochemical analysis, the photoelectrochemical measurements are carried out in a three-electrode cell with front-side illumination. The working electrode was mounted vertically facing the light source. A platinum wire served as the counter electrode, and an Ag/AgCl (saturated KCl) electrode was used as the reference. The electrolyte was 0.5 M Na2SO4 aqueous solution. Simulated sunlight was provided by a 300 W Xe arc lamp equipped with an AM 1.5G filter delivering an irradiance of 100 mW/cm2. The illuminated area of the photoanode is defined to 1 cm2. All electrodes were connected to an electrochemical workstation, and measurements were performed under ambient temperature without stirring. The photo for the setup was shown in Figure S1 in the SI. In our setup, the three electrodes are arranged in series along the light path, with the cathode closest to the illumination source, followed by the Ag/AgCl reference electrode, and the Pt counter electrode positioned last. This arrangement was chosen to maintain a compact and stable configuration within the photoelectrochemical cell. Although the reference electrode is illuminated, no abrupt potential fluctuations were observed during the measurements, as verified by stable baseline readings and consistent photocurrent responses. All measured potentials were converted to the reversible hydrogen electrode (RHE) scale by eq .

E(vs.RHE)=E(vs.Ag/AgCl)+0.05916×7+0.197=E(vs.Ag/AgCl)+0.611 1

Electrochemical tests including linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) were conducted using a PGSTAT204 potentiostat/galvanostat (Metrohm Autolab) with an FRA2 module. All measurements were repeated at least three times to ensure reproducibility and minimize experimental deviation. Each synthetic condition was repeated at least three times to ensure reproducibility. Control samples without NaOH etching or without MXene addition were fabricated and characterized under the same protocols for comparison.

3. Results and Discussion

3.1. Morpholgoy and Composition Examinations of BVO, E-BVO, MXene/BVO and MXene/E-BVO

To examine the morphological evolution resulting from alkaline etching and MXene incorporation on BVO, the SEM images of BVO, E-BVO, MXene/BVO and MXene/E-BVO are presented in Figure (a,e), (b,f), (c,g), and (d,h), respectively. Figure S2 in the SI shows the TEM image of MXene/E-BVO. The pristine BVO exhibits a uniform rod-like array, with individual rods showing slight curvature and polycrystalline features along their axis. The average diameter of these rods is around 150 nm. Upon alkaline etching, E-BVO displays thicker and more interconnected rods, implying that localized dissolution and redeposition occur during the treatment. This process likely promotes the fusion of adjacent rods, resulting in a denser morphology with reduced spacing between structures. While narrowed inter-rod gaps may suppress light penetration into deeper regions, the enhanced connectivity could improve charge transport efficiency across the photoanode. After MXene incorporation, an ultrathin and uniform layer is seen covering the BVO and E-BVO surface. The original rod-like structure is well-preserved, indicating that MXene addition does not interfere with the BVO morphology. The conductive MXene coating is expected to facilitate hole extraction and suppress surface charge recombination, thereby contributing to improved interfacial charge transfer kinetics. This surface modification is thus anticipated to enhance the overall photoelectrochemical performance in water oxidation reactions.

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SEM figures of (a, e) BVO, (b, f) E-BVO, (c, g) MXene/BVO and (d, h) MXene/E-BVO.

The phase compositions of BVO, E-BVO, MXene/BVO and MXene/E-BVO are examined through X-ray diffraction (XRD), with the corresponding patterns shown in Figure . All samples display diffraction peaks in the 2θ range of 15° to 35°, which correspond well to the (110), (011), (121), and (040) planes of monoclinic BiVO4 (JCPDS #14-0688), confirming that the desired crystal structure is maintained after alkaline etching and MXene addition. Peaks originating from the SnO2 layer (JCPDS #41-1445) are also detected, which stem from the fluorine-doped tin oxide (FTO) substrate commonly used for growing BVO photoanodes. These substrate-derived peaks serve as internal references and do not interfere with the assignment of BiVO4 phases due to their well-separated positions. No new diffraction signals are observed in the E-BVO, MXene/BVO and MXene/E-BVO samples, indicating that the structural integrity of the BiVO4 lattice remains intact following postsynthetic treatments. Characteristic MXene reflections are not visible, which can be attributed to its relatively low loading and possible delamination. A subtle peak shift near 2θ value of 28.9° (assigned to the (121) plane) is evident for MXene/BVO and MXene/E-BVO (Figure b), implying that interfacial interactions between MXene and BVO may introduce lattice strain or local distortion that can enhance charge separation and catalytic performance. This phenomenon likely arises from interfacial interactions between MXene sheets and the BVO surface during the post-treatment process. The negatively charged MXene surface, rich in functional groups such as −OH, –O, and –F, may interact with the surface Bi or V atoms via hydrogen bonding or electrostatic interactions. These interactions can introduce localized stress or distortion in the adjacent BiVO4 lattice, leading to a change in interplanar spacing and thus a measurable shift in XRD peak position. Such strain effects have been reported in oxide-MXene hybrids and are often associated with enhanced surface reactivity, modified band structure, or improved charge separation. All factors are beneficial for photoelectrochemical performance.

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XRD patterns of BVO, E-BVO, MXene/BVO and MXene/E-BVO in (a) wide and (b) narrow degree.

To investigate the chemical compositions and oxidation states in greater detail, X-ray photoelectron spectroscopy (XPS) measurements were conducted, and the corresponding spectra are shown in Figure . The Bi 4f spectra for BVO, E-BVO, MXene/BVO and MXene/E-BVO are shown in Figure a–d, respectively. Each spectrum presents two split orbitals of Bi 4f7/2 and Bi 4f5/2, centered at 158.6 and 163.9 eV, respectively. Peaks corresponding to Bi3+ and Bi5+ oxidation states are observed in all samples, with negligible shifts in binding energy, indicating that the electronic environment of Bi remains relatively unchanged after alkaline etching and MXene incorporation. The V 2p spectra of BVO, E-BVO,, MXene/BVO and MXene/E-BVO are presented in Figure e–h. The V 2p3/2 and V 2p1/2 peaks are respectively located near 516.8 and 524.3 eV, and are fitted with mixed V4+ and V5+ states. Similar intensity ratios and binding energies are found for all samples, suggesting minimal impact on vanadium chemistry. The O 1s spectra (Figure i–l show two deconvoluted peaks attributed to surface hydroxyl groups (OH–) at 531.4 eV and lattice oxygen (M-O) at 529.6 eV. The M-O component corresponds to metal–oxygen bonding within the BiVO4 structure. Finally, the Ti 2p spectra of MXene/BVO and MXene/E-BVO respectively shown in Figure m–n exhibits Ti 2p3/2 and 2p1/2 peaks respectively at 458.6 and 464.3 eV, assigned to Ti3+ and Ti4+ oxidation states. This confirms the successful incorporation of MXene into the composite. Based on XPS quantification, the atomic ratio of Ti to V in MXene/BVO and MXene/E-BVO is approximately 0.05 and 0.06, respectively, further validating the presence of MXene despite its low content.

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Bi 4f spectra of (a) BVO, (b) E-BVO, (c) MXene/BVO and (d) MXene/E-BVO; V 2p spectra of (e) BVO, (f) E-BVO, (g) MXene/BVO and (h) MXene/E-BVO; O 1s spectra of (i) BVO, (j) E-BVO, (k) MXene/BVO and (l) MXene/E-BVO; Ti 2p spectra of (m) MXene/BVO and (n) MXene/E-BVO.

The light absorption behaviors of BVO, E-BVO, MXene/BVO and MXene/E-BVO are analyzed by UV–vis spectroscopy, as shown in Figure a. All samples exhibit a pronounced absorption edge near 500 nm, characteristic of monoclinic BiVO4. Compared with the pristine BVO, the E-BVO sample shows a noticeable decrease in absorption intensity, which is likely attributed to morphological densification-specifically, the narrowed inter-rod spacing caused by alkaline etching that limits light penetration into deeper regions of the film. Interestingly, MXene/BVO and MXene/E-BVO samples recover much of the lost absorption, with intensity levels comparable to those of the pristine BVO. This improvement is possibly due to enhanced light scattering and surface plasmonic effects introduced by MXene sheets. To further assess the optical band structure, Tauc plots are derived from the absorbance spectra using the equation (αhν)2 vs hν (Figure b). The optical band gaps are extracted from the intercepts of the tangents, yielding values of 2.59, 2.55, 2.56, and 2.57 eV for BVO, E-BVO, MXene/BVO and MXene/E-BVO, respectively. These values are in close agreement with the reported band gap of ∼2.5 eV for monoclinic BiVO4. The minimal variations in band gap suggest that neither alkaline etching nor MXene incorporation significantly alters the bulk electronic structure. These results, combined with XPS findings, support the conclusion that the postmodification strategies primarily influence surface features and interfacial charge dynamics without disrupting the intrinsic band configuration of BVO.

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(a) The UV–vis spetrum and (b) Tauc plots of BVO, E-BVO, MXene/BVO and MXene/E-BVO.

3.2. Photoelectrochemical Catalytic Properties of BVO, E-BVO, MXene/BVO and MXene/E-BVO

The photoelectrochemical properties of BVO, E-BVO, MXene/BVO and MXene/E-BVO photoanodes were systematically analyzed to assess their light response, charge separation, and catalytic performance. Initially, chopped chronoamperometry measurements were performed at 1.23 VRHE to evaluate photoresponsive behavior under intermittent light exposure (Figure a). Upon illumination, all three electrodes exhibit a sharp increase in photocurrent, confirming their photoactive nature. The current rapidly reaches a peak value; however, for both BVO and E-BVO, the current gradually decays within each illumination cycle, suggesting the presence of charge recombination. In contrast, the MXene/E-BVO electrode maintains a much more stable and higher photocurrent throughout the light-on periods, indicating improved charge separation and suppressed recombination. The dark currents quickly drop to zero for all samples, reaffirming the photoresponsive origin of the observed currents. Furthermore, across prolonged measurement durations, the photocurrent of MXene/E-BVO remains considerably stable, whereas BVO and E-BVO both show gradual decreases, suggesting better long-term operational stability imparted by MXene incorporation. This enhancement is attributed to the excellent electrical conductivity and interfacial contact provided by MXene, which facilitates more efficient hole extraction and charge transport.

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(a) Transient current figure at 1.23 VRHE; (b) LSV at 20 mV/s (illumination); (c) ABPE plots; (d) Nyquist figure at 1.23 VRHE (illumination); (e) Mott–Schottky plots; (f) photocurrent retention and duration relationships of BVO, E-BVO, MXene/BVO and MXene/E-BVO electrodes.

The photoresponse characteristics were further evaluated using linear sweep voltammetry (LSV) under AM 1.5G illumination, with the results shown in Figure b. Table shows the photocurrent density of BVO, E-BVO, MXene/BVO and MXene/E-BVO. The photocurrent densities at 1.23 VRHE were determined to be 4.65, 5.13, 5.88, and 6.15 mA/cm2 for BVO, E-BVO, MXene/BVO and MXene/E-BVO, respectively. The increase in photocurrent for E-BVO compared to pristine BVO can be ascribed to the alkaline etching process, which induces surface restructuring and generates more catalytically active sites capable of enhancing hole accumulation and interfacial water oxidation. This enhancement occurs despite a reduction in optical absorption for E-BVO, indicating the greater influence of surface catalytic effects over light absorption in this case. The morphological restructuring of BVO induced by alkaline etching plays a significant role in enhancing its PEC performance. SEM analysis reveals that etching transforms the loosely packed rod-like arrays of pristine BVO into a denser and more interconnected network in E-BVO. This densification likely arises from partial dissolution and redeposition, which promotes fusion between adjacent rods and reduces inter-rod spacing. The tighter structure enhances electrical connectivity across the photoanode surface, facilitating more efficient in-plane charge transport and minimizing the risk of carrier trapping at grain boundaries. In addition, the increased surface roughness and interfacial area introduced by the etched morphology generate more catalytically active sites for water oxidation, promoting hole utilization and suppressing surface recombination. However, the morphological densification also slightly reduces light penetration due to narrowed voids, which can decrease overall light absorption, as confirmed by UV–vis measurements. Nevertheless, this optical loss is compensated by improved charge extraction and higher surface activity. The trade-off between light absorption and charge transport highlights the importance of morphological optimization in achieving a balance between photon harvesting and catalytic efficiency. Moreover, the MXene/E-BVO electrode exhibits the highest photocurrent density, confirming that the incorporation of MXene introduces additional conductive pathways and promotes rapid charge transfer across the interface. Onset potentials were also determined to be 0.25, 0.31, 0.22, and 0.20 VRHE for BVO, E-BVO, MXene/BVO and MXene/E-BVO, respectively. The higher onset potential of E-BVO may originate from increased defect levels that elevate the overpotential required for water oxidation. Conversely, the significantly reduced onset potential in MXene/E-BVO suggests a more favorable energy alignment and reduced kinetic barrier for photoelectrochemical water oxidation, likely due to better charge collection and faster interfacial hole transfer enabled by the MXene layer. To further clarify the individual contribution of alkaline etching, a control experiment was conducted by incorporating MXene into pristine BVO without prior etching. The resulting MXene/BVO electrode exhibits a photocurrent density of 5.46 mA/cm2 at 1.23 V vs RHE, as shown in Figure S3 in the SI. Although this value is higher than that of pristine BVO (4.65 mA/cm2), it remains lower than that of the MXene/E-BVO photoanode (6.15 mA/cm2), indicating that alkaline etching contributes positively to PEC performance beyond what is achieved by MXene alone. This enhancement is attributed to the increased surface defect density and improved catalytic site availability introduced during etching, which facilitate hole accumulation and interfacial reaction kinetics. Meanwhile, MXene provides a conductive pathway for efficient hole extraction. The higher performance of MXene/E-BVO compared to both E-BVO and MXene/BVO confirms the synergistic effect of combining surface restructuring with interfacial engineering, resulting in more efficient charge separation, reduced recombination, and improved water oxidation efficiency. Applied bias photon-to-current efficiency (ABPE) plots were derived from the LSV curves using eq and are presented in Figure c.

ABPE=J×(1.23−Vbias)Pin×100% 2

The highest ABPE values for BVO, E-BVO, MXene/BVO and MXene/E-BVO were found to be 1.67% at 0.72 VRHE, 1.79% at 0.71 VRHE, 2.16% at 0.74 VRHE and 2.52% at 0.75 VRHE, respectively. The MXene/E-BVO photoanode clearly achieves the best PEC efficiency, which can be attributed to the synergistic effect of alkaline etching and MXene incorporation. While etching generates more surface defect sites that serve as hole traps and reaction centers, the presence of MXene enhances conductivity and facilitates efficient hole transport, jointly contributing to improved solar-to-chemical energy conversion efficiency.

1. Electrochemical Parameters of BVO, E-BVO, MXene/BVO and MXene/E-BVO .

electrode photocurrent density (mA/cm 2 @1.23 V RHE ) onset potential (V RHE ) R CT (Ω) carrier density (cm –3 )
BVO 4.65 ± 0.18 0.25 244.6 1.72 × 1023
E-BVO 5.13 ± 0.21 0.31 192.6 1.68 × 1024
MXene/BVO 5.88 ± 0.14 0.22 180.2 2.58 × 1024
MXene/E-BVO 6.15 ± 0.32 0.20 116.6 4.12 × 1024
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a

Three electrodes are tested to ensure reproducibility.

Electrochemical impedance spectroscopy (EIS) was carried out at 1.23 VRHE under illumination, and the Nyquist plots are displayed in Figure d. The fitting was conducted using the equivalent circuit model shown in the inset. Table shows the charge-transfer resistance (R CT) values of BVO, E-BVO, MXene/BVO and MXene/E-BVO. The R CT values extracted from fitting are 244.6 Ω for BVO, 192.6 Ω for E-BVO, 180.2 Ω for MXene/BVO and 116.6 Ω for MXene/E-BVO. The reduction in R CT from BVO to E-BVO reflects improved interfacial conductivity after etching, while the lowest R CT in MXene/E-BVO highlights the contribution of MXene to accelerating charge transfer at the electrode/electrolyte interface. This reduction in resistance plays a crucial role in minimizing energy loss during PEC operation and contributes directly to higher photocurrent and ABPE values. To further analyze bulk charge properties, Mott–Schottky analysis was performed and the plots are shown in Figure e. The carrier densities were calculated from the slope of the linear regions using the Mott–Schottky equation. Table shows the carrier densities of BVO, E-BVO, MXene/BVO and MXene/E-BVO. The extracted donor concentrations are 1.73 × 1023, 1.68 × 1024, 2.58 × 1024 and 4.12 × 1024 cm–3 for BVO, E-BVO, MXene/BVO and MXene/E-BVO, respectively. The nearly 10-fold increase in carrier density for E-BVO confirms that alkaline treatment introduces donor-like surface states, while the additional increase upon MXene incorporation demonstrates that MXene also contributes to enhancing charge density, likely by improving electron mobility and maintaining higher levels of surface charge accumulation. The enhanced photoelectrochemical performance of the MXene/E-BVO electrode can be further correlated with the structural changes observed by XRD. A subtle shift in the (121) diffraction peak is detected for the MXene/E-BVO sample, suggesting the presence of interfacial lattice strain induced by interactions between MXene nanosheets and the BVO lattice. This strain may alter the local electronic environment, modify band bending at the interface, and facilitate charge separation and transport. These effects are supported by electrochemical data, where MXene/E-BVO shows the lowest charge-transfer resistance (116.6 Ω) and the highest donor density (4.12 × 1024 cm–3), as well as the highest photocurrent density (6.15 mA/cm2 at 1.23 V vs RHE). Such improvements indicate more efficient charge extraction and suppressed recombination, which are consistent with lattice strain–induced interfacial enhancement. Therefore, the structural distortion observed via XRD is not merely a crystallographic artifact but a contributing factor to the improved PEC performance of the MXene-modified photoanode. Finally, the long-term operational stability of the photoanodes was evaluated through chronoamperometric measurements over 10,000 s at 1.23 VRHE under AM 1.5G illumination (Figure f). Photocurrent retention values of 74.8, 80.6, 90.4, and 93.4% were recorded for BVO, E-BVO, MXene/BVO and MXene/E-BVO, respectively. The higher stability of MXene/E-BVO highlights the dual role of MXene not only in enhancing PEC activity but also in mitigating photocorrosion and suppressing performance degradation over time. The combination of morphological tuning via alkaline etching and interfacial engineering via MXene incorporation provides a viable strategy to achieve stable and efficient PEC water oxidation. Postcatalysis characterizations for MXene/E-BVO, including SEM and XRD, are shown in Figure S4 in the SI. The morphology and crystallinity of MXene/E-BVO remain largely unchanged before and after the stability test. These results demonstrate the excellent stability of MXene/E-BVO as a photocatalyst for the oxygen evolution reaction

The enhanced photoelectrochemical performance of the MXene/E-BVO system can be primarily attributed to the improved charge-transfer dynamics enabled by the MXene layer. Upon illumination, BVO absorbs visible light and generates electron–hole pairs. The photogenerated electrons are transported through the E-BVO matrix toward the FTO substrate, while the holes migrate to the surface. In the absence of surface engineering, holes at BVO surface are prone to recombination due to limited mobility and trap states. Alkaline etching introduces surface defects that act as hole traps and catalytically active sites, facilitating interfacial water oxidation. Importantly, the incorporation of MXene forms an ultrathin, conductive network on BVO surface that significantly accelerates hole extraction. Due to its high electrical conductivity and the presence of functional surface groups, MXene provides a favorable energy alignment for hole transfer and also acts as an electron-blocking layer, minimizing back recombination. This dual effect promotes spatial charge separation. Holes are rapidly shuttled from the BVO bulk to the surface and then into water oxidation reactions, while electrons move toward the FTO substrate. Furthermore, the close interfacial contact between MXene and E-BVO may introduce local electric fields or strain-induced band bending, further assisting carrier separation.

The schematic illustration of the MXene/E-BVO photoanode architecture and its associated charge transfer mechanism is shown in Scheme . The configuration consists of a FTO glass substrate, a photoactive E-BVO layer, and an ultrathin MXene coating deposited on the surface. Upon illumination, BVO absorbs incident photons and generates electron–hole pairs. The photogenerated electrons are transported downward through the E-BVO matrix and collected by the FTO substrate, while holes migrate toward the surface to drive the water oxidation reaction. Alkaline etching induces the formation of abundant surface defects on E-BVO, which serve as catalytically active sites and efficient hole traps, thereby improving the likelihood of interfacial redox events. Simultaneously, the conductive MXene layer provides a favorable pathway for hole transport by bridging multiple active sites and suppressing surface recombination. This dual modification, via surface activation and interfacial engineering, not only promotes directional carrier separation but also enhances charge mobility and extraction efficiency. Consequently, this engineered system exhibits significantly improved photoelectrochemical performance, attributed to the synergistic effects of enhanced catalytic activity, reduced recombination, and efficient charge collection across the MXene/E-BVO/FTO interface.

2. Illustration of Configuration and Charge-Transfer Paths for MXene/E-BVO System.

2

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4. Conclusions

In this study, a synergistic modification strategy combining alkaline etching and MXene incorporation was applied to BVO for the first time to develop an efficient PEC catalyst for water oxidation. Alkaline etching effectively introduced surface defects that serve as electroactive sites, facilitating hole accumulation and enhancing the kinetics of water oxidation. Concurrently, the introduction of MXene significantly improved the electrical conductivity of the composite, forming conductive networks that promote rapid charge transport and reduce interfacial recombination. The optimized MXene/E-BVO photoanode achieved a high photocurrent density of 6.15 mA/cm2, a low charge transfer resistance of 116.6 Ω, and a remarkably high carrier density of 4.12 × 102 cm–3. Additionally, the photocurrent retention of 93.4% after 10,000 s of continuous illumination underscores its enhanced operational stability. These findings demonstrate the effectiveness of combining surface and interface engineering to overcome intrinsic limitations of BVO. Future efforts may focus on fine-tuning the MXene layer in terms of thickness, phase composition, or spatial integration, as well as exploring alternative surface engineering strategies in tandem with alkaline treatment. Such developments could further optimize charge separation and interfacial charge dynamics toward scalable, durable solar fuel generation platforms.

Supplementary Material

ao5c06250_si_001.pdf (439.7KB, pdf)

Acknowledgments

This work is also assisted by Precision Analysis and Material Research Center, NTUT. This work was supported by University System of Taipei Joint Research Program (USTP-NTUT-TMU-114-02). This work was supported by National Science and Technology Council (NSTC) in Taiwan, under Grant 111-2221-E-027-071-MY3 and 113-2221-E-027-010-MY3.

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsomega.5c06250.

  • Experiments, a photo for measurement setup, TEM and LSV of MXene/BVO, SEM and XRD of MXene/E-BVO before and after stability test (PDF)

The authors declare no competing financial interest.

References

  1. Megía P. J., Vizcaíno A. J., Calles J. A., Carrero A.. Hydrogen Production Technologies: From Fossil Fuels toward Renewable Sources. A Mini Review. Energy Fuels. 2021;35(20):16403–16415. doi: 10.1021/acs.energyfuels.1c02501. [DOI] [Google Scholar]
  2. Worku, A. K. ; Ayele, D. W. ; Deepak, D. B. ; Gebreyohannes, A. Y. ; Agegnehu, S. D. ; Kolhe, M. L. . Recent Advances and Challenges of Hydrogen Production Technologies via Renewable Energy Sources 2024. 5 5 2300273 10.1002/aesr.202300273. [DOI] [Google Scholar]
  3. Baum Z. J., Diaz L. L., Konovalova T., Zhou Q. A.. Materials Research Directions Toward a Green Hydrogen Economy: A Review. ACS Omega. 2022;7(37):32908–32935. doi: 10.1021/acsomega.2c03996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Ishaq H., Dincer I., Crawford C.. A review on hydrogen production and utilization: Challenges and opportunities. Int. J. Hydrogen Energy. 2022;47(62):26238–26264. doi: 10.1016/j.ijhydene.2021.11.149. [DOI] [Google Scholar]
  5. Afanasev P., Askarova A., Alekhina T., Popov E., Markovic S., Mukhametdinova A., Cheremisin A., Mukhina E.. An overview of hydrogen production methods: Focus on hydrocarbon feedstock. Int. J. Hydrogen Energy. 2024;78:805–828. doi: 10.1016/j.ijhydene.2024.06.369. [DOI] [Google Scholar]
  6. Kalamaras, C. M. ; Efstathiou, A. M. . Hydrogen Production Technologies: Current State and Future Developments. In Conference Papers in Science 2013; p 690627 10.1155/2013/690627. [DOI] [Google Scholar]; (acccessed April 4, 20254)
  7. Qureshi F., Tahir M.. Photoelectrochemical water splitting with engineering aspects for hydrogen production: Recent advances, strategies and challenges. Int. J. Hydrogen Energy. 2024;69:760–776. doi: 10.1016/j.ijhydene.2024.05.039. [DOI] [Google Scholar]
  8. Kumar M., Meena B., Subramanyam P., Suryakala D., Subrahmanyam C.. Recent trends in photoelectrochemical water splitting: the role of cocatalysts. NPG Asia Mater. 2022;14(1):88. doi: 10.1038/s41427-022-00436-x. [DOI] [Google Scholar]
  9. Chen P., Kang B., Liu P., Cheng X., Zhong S., Wang X., Fang B.. Passivation strategies for enhanced photoelectrochemical water splitting. J. Power Sources. 2025;628:235860. doi: 10.1016/j.jpowsour.2024.235860. [DOI] [Google Scholar]
  10. Kubendhiran S., Chung R.-J., Yougbaré S., Lin L.-Y.. Rational design of W-doped BiVO4 photoanode coupled with FeOOH for highly efficient photoelectrochemical catalyzing water oxidation. Int. J. Hydrogen Energy. 2022;47(63):27012–27022. doi: 10.1016/j.ijhydene.2022.06.048. [DOI] [Google Scholar]
  11. Pai H., Kuo T.-R., Chung R.-J., Kubendhiran S., Yougbaré S., Lin L.-Y.. Enhanced photocurrent density for photoelectrochemical catalyzing water oxidation using novel W-doped BiVO4 and metal organic framework composites. J. Colloid Interface Sci. 2022;624:515–526. doi: 10.1016/j.jcis.2022.05.169. [DOI] [PubMed] [Google Scholar]
  12. Chen Y.-S., Lin L.-Y.. Novel synthesis of highly ordered BiVO4 nanorod array for photoelectrochemical water oxidation using a facile solution process. J. Power Sources. 2019;436:226842. doi: 10.1016/j.jpowsour.2019.226842. [DOI] [Google Scholar]
  13. Chen Y.-S., Lin L.-Y.. Synthesis of monoclinic BiVO4 nanorod array for photoelectrochemical water oxidation: Seed layer effects on growth of BiVO4 nanorod array. Electrochim. Acta. 2018;285:164–171. doi: 10.1016/j.electacta.2018.07.232. [DOI] [Google Scholar]
  14. Kubendhiran S., Chung R.-J., Yougbaré S., Lin L.-Y., Wu Y.-F.. Enhanced photoelectrochemical water oxidation on BiVO4 by addition of ZnCo-MOFs as effective hole transfer co-catalyst. Int. J. Hydrogen Energy. 2023;48(1):101–112. doi: 10.1016/j.ijhydene.2022.09.201. [DOI] [Google Scholar]
  15. Liu L., Ruan M., Wang C., Liu Z.. Optimization of the BiO8 polar group of BiVO4 by Cl--embedded modification to manipulate bulk-surface carrier separation for achieving efficient Piezo-PEC water oxidation. Appl. Catal., B. 2024;354:124117. doi: 10.1016/j.apcatb.2024.124117. [DOI] [Google Scholar]
  16. Liu L., Ruan M., Wang C., Zhong T., Zhou M., Liu Z.. Dual Functions of Optimized FeCo Oxyhydroxide Composition in BiVO4 Photoanodes with Bi Vacancy for Photocorrosion Inhibition and Improved Photoelectrochemical Performance. ACS Appl. Mater. Interfaces. 2025;17(19):28309–28320. doi: 10.1021/acsami.5c05130. [DOI] [PubMed] [Google Scholar]
  17. Fang G., Liu Z., Han C.. Enhancing the PEC water splitting performance of BiVO4 co-modifying with NiFeOOH and Co-Pi double layer cocatalysts. Appl. Surf. Sci. 2020;515:146095. doi: 10.1016/j.apsusc.2020.146095. [DOI] [Google Scholar]
  18. Fang G., Liu Z., Han C., Ma X., Lv H., Huang C., Cheng Z., Tong Z., Wang P.. CoNiO2 as a novel water oxidation cocatalyst to enhance PEC water splitting performance of BiVO4 . Chem. Commun. 2020;56(64):9158–9161. doi: 10.1039/D0CC03516E. [DOI] [PubMed] [Google Scholar]
  19. Fang G., Liu Z., Han C., Wang P., Ma X., Lv H., Huang C., Cheng Z., Tong Z.. Promising CoFe-NiOOH Ternary Polymetallic Cocatalyst for BiVO4-Based Photoanodes in Photoelectrochemical Water Splitting. ACS Appl. Energy Mater. 2021;4(4):3842–3850. doi: 10.1021/acsaem.1c00247. [DOI] [Google Scholar]
  20. Wu Y.-T., Lin J.-Y., Lin L.-Y., Chen Y.-S., Geng D.-S.. Facile solid-state synthesis of heteroatom-doped and alkaline-treated bismuth vanadate for photocatalyzing methylene blue degradation and water oxidation. Mater. Sci. Semicond. Process. 2020;117:105180. doi: 10.1016/j.mssp.2020.105180. [DOI] [Google Scholar]
  21. Ma J.-S., Lin L.-Y., Chen Y.-S.. Facile solid-state synthesis for producing molybdenum and tungsten co-doped monoclinic BiVO4 as the photocatalyst for photoelectrochemical water oxidation. Int. J. Hydrogen Energy. 2019;44(16):7905–7914. doi: 10.1016/j.ijhydene.2019.02.077. [DOI] [Google Scholar]
  22. Lai B.-R., Lin L.-Y., Xiao B.-C., Chen Y.-S.. Facile synthesis of bismuth vanadate/bismuth oxide heterojunction for enhancing visible light-responsive photoelectrochemical performance. J. Taiwan Inst. Chem. Eng. 2019;100:178–185. doi: 10.1016/j.jtice.2019.04.020. [DOI] [Google Scholar]
  23. Cheng T.-M., Yang Y.-Y., Chiu Y.-H., Kongvarhodom C., Saukani M., Yougbaré S., Chen H.-M., Lin L.-Y.. Decoration of novel molybdenum-based bimetallic oxide on bismuth vanadate as photoelectrochemical catalysts for efficient water oxidation. Int. J. Hydrogen Energy. 2025;114:201–208. doi: 10.1016/j.ijhydene.2025.03.043. [DOI] [Google Scholar]
  24. Chiu Y.-H., Kongvarhodom C., Saukani M., Yougbaré S., Chen H.-M., Wu Y.-F., Lin L.-Y.. Strategic integration of nickel tellurium oxide and cobalt iron prussian blue analogue into bismuth vanadate for enhanced photoelectrochemical water oxidation. Int. J. Hydrogen Energy. 2024;89:142–150. doi: 10.1016/j.ijhydene.2024.09.309. [DOI] [Google Scholar]
  25. Chiu Y.-H., Chung R.-J., Kongvarhodom C., Saukani M., Yougbaré S., Chen H.-M., Wu Y.-F., Lin L.-Y.. Facile Combination of Bismuth Vanadate with Nickel Tellurium Oxide for Efficient Photoelectrochemical Catalysis of Water Oxidation Reactions. ACS Appl. Mater. Interfaces. 2024;16(37):49249–49261. doi: 10.1021/acsami.4c07117. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Tao S.-M., Lin L.-Y.. Design of efficient Mn-doped α-Fe2O3/Ti-doped α-Fe2O3 homojunction for catalyzing photoelectrochemical water splitting. Int. J. Hydrogen Energy. 2020;45(11):6487–6499. doi: 10.1016/j.ijhydene.2019.12.188. [DOI] [Google Scholar]
  27. Wu Y.-T., Lin L.-Y., Tao S.-M., Chen Y.-S., Ma J.-S., Lee P.-Y., Sung Y.-S.. Novel in Situ Synthesis of BiVO4 Photocatalyst/Co3(PO4)2 Co-Catalyst Powder via the One-Step Solid-State Process for Photoelectrochemical Catalyzing Water Oxidation. ACS Sustainable Chem. Eng. 2020;8(7):2948–2956. doi: 10.1021/acssuschemeng.9b07517. [DOI] [Google Scholar]
  28. Li C., Chen M., Xie Y., Jian J., Wang H., Jia L.. Boosting the solar water oxidation performance of BiVO4 photoanode via non-stoichiometric ratio drived surface reconstruction. J. Power Sources. 2022;528:231242. doi: 10.1016/j.jpowsour.2022.231242. [DOI] [Google Scholar]
  29. Feng C., Liu L., Fu H., Zhan F., Jia H., Cheng X., Yu F., Zhou Q., Bian Z., Zhang B.. Structural tuning of BiVO4/MnFe-MOF photoanodes boosts hole extraction for photoelectrochemical water splitting. Catal. Sci. Technol. 2024;14(17):4860–4868. doi: 10.1039/D4CY00836G. [DOI] [Google Scholar]
  30. Tong H., Jiang Y., Xia L.. Enhancing photoelectrochemical water oxidation activity of BiVO4 photoanode through the Co-catalytic effect of Ni­(OH)2 and carbon quantum dots. Int. J. Hydrogen Energy. 2023;48(94):36694–36706. doi: 10.1016/j.ijhydene.2023.06.003. [DOI] [Google Scholar]
  31. Song Y.-T., Lin L.-Y., Chen Y.-S., Chen H.-Q., Ni Z.-D., Tu C.-C., Yang S.-S.. Novel TiO2/Sb2S3 heterojunction with whole visible-light response for photoelectrochemical water splitting reactions. RSC Adv. 2016;6(54):49130–49137. doi: 10.1039/C6RA04094B. [DOI] [Google Scholar]
  32. Song Y.-T., Lin L.-Y., Hong J.-Y.. Enhanced Visible-light Response and Conductivity of the TiO2/reduced graphene oxide/Sb2S3 Heterojunction for Photoelectrochemical Water Oxidation. Electrochim. Acta. 2016;211:576–585. doi: 10.1016/j.electacta.2016.06.074. [DOI] [Google Scholar]
  33. Fu L., Li Z., Shang X.. Recent surficial modification strategies on BiVO4 based photoanodes for photoelectrochemical water splitting enhancement. Int. J. Hydrogen Energy. 2024;55:611–624. doi: 10.1016/j.ijhydene.2023.11.253. [DOI] [Google Scholar]
  34. Wang X., Zhang Y., Deng S., Lin S.. Coupling surface modification with cocatalyst deposition on BiVO4 photoanode to enhance charge transfer for efficient solar-driven water splitting. Int. J. Hydrogen Energy. 2023;48(63):24320–24327. doi: 10.1016/j.ijhydene.2023.03.280. [DOI] [Google Scholar]
  35. Yang P., Shi H., Wu H., Yu D., Huang L., Wu Y., Gong X., Xiao P., Zhang Y.. Manipulating the surface states of BiVO4 through electrochemical reduction for enhanced PEC water oxidation. Nanoscale. 2023;15(9):4536–4545. doi: 10.1039/D2NR07138J. [DOI] [PubMed] [Google Scholar]
  36. Cheng T.-M., Chuang K.-J., Huang H.-W., Chen H.-M., Fan Y.-M., Yougbaré S., Lin L.-Y., Wu Y.-F.. Enhancements on oxygen vacancy and light absorption of alkaline-etched BiVO4 for photoelectrochemical water oxidation. Int. J. Hydrogen Energy. 2023;48(91):35561–35571. doi: 10.1016/j.ijhydene.2023.05.328. [DOI] [Google Scholar]
  37. Saada, H. ; Abdallah, R. ; Fabre, B. ; Floner, D. ; Fryars, S. ; Vacher, A. ; Dorcet, V. ; Meriadec, C. ; Ababou-Girard, S. ; Loget, G. . Boosting the Performance of BiVO4 Prepared through Alkaline Electrodeposition with an Amorphous Fe Co-Catalyst. 2019, 6 (3), 613–617. 10.1002/celc.201801443. [DOI] [Google Scholar]
  38. Hsu C.-C., Chuang K.-J., Huang H.-W., Pan B.-J., Chen H.-M., Husain S., Yougbaré S., Hsiao Y.-C., Wu Y.-F., Lin L.-Y.. Modifying BiVO4 as a photocatalyst for water oxidation using constant-duration alkaline-etched post treatments. New J. Chem. 2024;48(2):569–577. doi: 10.1039/D3NJ04544G. [DOI] [Google Scholar]
  39. Tai P.-Y., Sakthivel M., Peng Y.-J., Kubendhiran S., Lin L.-Y., Ho K.-C.. In Situ Growing Te-Doped Ni–Mn Layered Double Hydroxide on a Cetyltrimethylammonium Bromide-Modified MXene Conductive Layer for Binder-Free Supercapacitors. ACS Appl. Energy Mater. 2025;8:4122. doi: 10.1021/acsaem.4c02840. [DOI] [Google Scholar]
  40. Chen F.-S., Jin Z.-X., Sakthivel M., Lin L.-Y., Ho K.-C.. Facile construction of nickel cobalt boride and layered Ti-MXene heterostructure as high-energy-density electroactive materials of supercapacitors. J. Energy Storage. 2025;131:115856. doi: 10.1016/j.est.2025.115856. [DOI] [Google Scholar]
  41. Lee P.-Y., Chiou Y.-R., Cheng C.-S., Chen Y.-C., Kongvarhodom C., Chen H.-M., Yougbaré S., Husain S., Ho K.-C., Kuo T.-R., Lin L. Y.. Incorporating self-assembled MXene to improve electrical conductivity of novel ZIF67 derivatives induced by NH4BF4 and NH4HF2 for energy storage. J. Energy Storage. 2024;82:110589. doi: 10.1016/j.est.2024.110589. [DOI] [Google Scholar]
  42. Lee P.-Y., Cheng T.-M., Yougbaré S., Lin L.-Y.. Design of novel self-assembled MXene and ZIF67 derivative composites as efficient electroactive material of energy storage device. J. Colloid Interface Sci. 2022;618:219–228. doi: 10.1016/j.jcis.2022.03.092. [DOI] [PubMed] [Google Scholar]
  43. Bai W., Zhou Y., Peng G., Wang J., Li A., Corvini P. F.-X.. Engineering efficient hole transport layer Ferrihydrite-MXene on BiVO4 photoanodes for photoelectrochemical water splitting: Work function and conductivity regulated. Appl. Catal., B. 2022;315:121606. doi: 10.1016/j.apcatb.2022.121606. [DOI] [Google Scholar]
  44. Jahangir T. N., Kandiel T. A., Fatima W., Abdalmwla M. A., Al-Ahmed A., Ahmed A. Y.. Insights into the role of Co3O4/Ti3C2 MXene hybrid material in photoelectrochemical water oxidation over BiVO4 photoanode. J. Environ. Chem. Eng. 2024;12(3):113058. doi: 10.1016/j.jece.2024.113058. [DOI] [Google Scholar]
  45. Zhong S., Kang B., Cheng X., Chen P., Fang B.. Construction of a Co-MOF/MXene/BiVO4 Composite Photoanode for Efficient Photoelectrochemical Water Splitting. ACS Sustainable Chem. Eng. 2024;12(3):1233–1246. doi: 10.1021/acssuschemeng.3c05782. [DOI] [Google Scholar]
  46. Ma J.-S., Lin L.-Y.. Efficient bismuth vanadate homojunction with zinc and tungsten doping via simple successive spin-coating process for photoelectrochemical catalyzing water oxidation. J. Power Sources. 2021;499:229964. doi: 10.1016/j.jpowsour.2021.229964. [DOI] [Google Scholar]
  47. Kuo T.-R., Huang H.-W., Kongvarhodom C., Saukani M., Yougbaré S., Chen H.-M., Lin L.-Y.. Efficiently catalyzing photo-oxidation of water by surface engineering of bismuth vanadate with nickel molybdenum oxide coverages. Int. J. Hydrogen Energy. 2024;51:613–622. doi: 10.1016/j.ijhydene.2023.10.147. [DOI] [Google Scholar]
  48. Li J., Chen C., Li J., Li S., Dong C.. Synthesis of tin-glycerate and it conversion into SnO2spheres for highly sensitive low-ppm-level acetone detection. J. Mater. Sci.:Mater. Electron. 2020;31(19):16539–16547. doi: 10.1007/s10854-020-04208-7. [DOI] [Google Scholar]
  49. Sajid M. M., Khan S. B., Javed Y., Amin N., Zhang Z., Shad N. A., Zhai H.. Bismuth vanadate/MXene (BiVO4/Ti3C2) heterojunction composite: enhanced interfacial control charge transfer for highly efficient visible light photocatalytic activity. Environ. Sci. Pollut. Res. 2021;28(27):35911–35923. doi: 10.1007/s11356-021-13315-9. [DOI] [PubMed] [Google Scholar]
  50. Chen Y.-S., Lin L.-Y., Lin H.-Y.. Molybdenum doping effects for bismuth vanadate photocatalysts on electrochemical performances using the solution process. Int. J. Hydrogen Energy. 2020;45(1):667–674. doi: 10.1016/j.ijhydene.2019.10.222. [DOI] [Google Scholar]
  51. Walsh A., Yan Y., Huda M. N., Al-Jassim M. M., Wei S.-H.. Band Edge Electronic Structure of BiVO4: Elucidating the Role of the Bi s and V d Orbitals. Chem. Mater. 2009;21(3):547–551. doi: 10.1021/cm802894z. [DOI] [Google Scholar]
  52. Hong W.-L., Lin L.-Y.. Influence of structure directing agents on synthesizing battery-type materials for flexible battery supercapacitor hybrids. J. Taiwan Inst. Chem. Eng. 2019;100:105–116. doi: 10.1016/j.jtice.2019.04.010. [DOI] [Google Scholar]
  53. Lin H.-S., Lin L.-Y.. Improving Visible-light Responses and Electric Conductivities by Incorporating Sb2S3 and Reduced Graphene Oxide in a WO3 Nanoplate Array for Photoelectrochemical Water Oxidation. Electrochim. Acta. 2017;252:235–244. doi: 10.1016/j.electacta.2017.09.007. [DOI] [Google Scholar]

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