Table 3.

Photocurrents of doped CuO, and CuO composites photoelectrodes prepared by different synthesis procedures for PEC water splitting

Sn.	Type and morphology of photocathode	Fabrication process	Photocurrent density	Ref.
1	2 at% Li doped CuO	Flame spray pyrolysis	1.69 mA cm−2 at −0.55V versus Ag/AgCl	[ 227 ]
2	Ni/CuO fibers	Electrospinning	2.6 mA cm−2 at −0.5V versus Ag/AgCl	[ 228 ]
3	Al‐incorporated CuO (CuO:Al)	Radio frequency	3.7 mA cm−2 at 0V versus RHE	[ 229 ]
4	P(CuO/CuO:Al)/nZnO:Al/TiO2/Au–Pd	Radio frequency	5.4 mA cm−2 at 0V versus RHE	[ 229 ]
5	Cu2O/CuO nanorods	Physical vapor deposition	0.24 mA cm−2 at −0.5 V versus Ag/AgCl	[ 230 ]
6	Ni‐doped CuO nanorods	Chemical bath deposition	1.75 mA cm−2 at −0.55V versus SCE	[ 231 ]
7	Cu/Cu2O/CuO nanowires	Thermal oxidation	1.8 mA cm−2 at 0V versus RHE	[ 118 ]
8	CuO/Cu2O	Electrodeposition + annealing	0.451 mA cm−2 at −0.3V versus Ag/AgCl	[ 232 ]
9	CuO/Cu2O grass appendage‐like	Electrodeposition	1.44 mA cm−2 at −0.7 V versus Ag/AgCl	[ 233 ]
10	CuO/SrTiO3 nanostructure	Sol–gel spin‐coating	1.85 mA cm−2 at −0.9 V versus SCE	[ 234 ]
11	Cu2O/CuO/WO3	Electrodeposition and annealing	1.9 mA cm−2 at 0 V versus RHE	[ 235 ]
12	CuO/CuWO4	Electrodeposition and annealing	2.8 mA cm−2 at 0 V versus RHE	[ 235 ]
13	Cu2O/CuO composite	Electrodeposition followed by anodization	1.54 mA cm−2 at 0 V versus RHE	[ 220 ]
14	Cu2O/CuO bilayered composites	Electrodeposition and a subsequent thermal oxidation	3.15 mA cm−2 at 0.4 V versus RHE	[ 35 ]
15	ZnO/CuO branched nanowires	Thermal oxidation and hydrothermal growth methods	1.3 mA cm−2 at 0 V versus RHE	[ 206 ]
16	CuO/ZnO nanorod nano branch	Direct thermal oxidation of Cu nanorods	0.9 mA cm−2 at 0.5 V versus RHE	[ 65 ]
17	CuO/ZnO core/shell heterostructure NWs	Oxidation method followed by thermal decomposition	1.54 mA cm−2 at 1 V versus RHE	[ 47 ]
18	p‐CuO/n‐ZnO heterojunction nanoarrays	Water bath reaction process together with the atomic layer deposition (ALD) technology	0.9 mA cm−2 at 0.2 V versus RHE	[ 222 ]
19	CuO/ZnO nanowire	Electro‐deposition of Cu Film followed by a subsequent chemical oxidation and dip‐coating methods	8.1 mA cm−2 at 0 V versus RHE	[ 223 ]
20	CuO/CdS thin film	Chemical bath deposition followed by ALD‐TiO2 onto the CuO thin film	1.68 mA cm−2 at 0 V versus RHE	[ 224 ]
21	CuO nanorod/Al2O3	Modified‐chemical bath deposition followed by thermal evaporation	2.26 mA cm−2 at 0.55 V versus, SCE	[ 226 ]
22	CuO nanofibers	Electrospinning	0.16 mA cm−2 at 0.4 V versus RHE	[ 200 ]
23	Ti‐alloyed CuO	RF magnetron co‐sputtering	0.2 mA cm−2 at −0.3 V versus RHE	[ 216 ]
24	CuO/Pd nanoparticles	Solution synthesis, spin‐coating, and thermal treatment processes	0.8 mA cm−2 at 0.44 V versus RHE	[ 54 ]
25	WO3/CuO heterojunction	Electrodeposition	0.18 mA cm−2 at −0.7 V versus RHE	[ 221 ]
26	Cu2O/CuO decorated with nickel	Electrolysis deposition, thermal annealing in air and spin‐coating processes	4.3 mA cm−2 at 0 V versus RHE	[ 208 ]
27	CuO photoelectrode with Ni‐doped seed layer	M‐CBD process	1.33 mA cm−2 at 0 V versus RHE	[ 58 ]
28	CuO/Cu2O shell/core heterostructure	Electrochemical anodization + annealing	1.9 mA cm−2 at 0.3 V versus Ag/AgCl	[ 218 ]
29	Cu2O/CuO	Electrolysis+ annealing	2.1 mA cm−2 at 0 V versus RHE	[ 208 ]
30	Ni decorated Cu2O/CuO	Electrolysis + hydrothermal + spin‐coating	4.3 mA cm−2 at 0 V versus RHE	[ 208 ]
31	TiO2 in Cu2O–CuO heterojunction	Anodising Cu foil: TiO2/CuO	2.4 mA cm−2 at 0 V versus RHE	[ 236 ]
32	Cu2O/CuO nanowires	Calcination of the anodized Cu2O	1.3 mA cm−2 at 0 V versus RHE	[ 236 ]