Figure 7.

a) LSV curves of HER and b) the calculated $\mathrm{\Delta }{\text{G}}_{{\text{H}}^{\text{*}}}$ of pure MoS₂ and Co‐doped MoS₂. a,b) Reproduced with permission.^{[ 164 ]} Copyright 2018, Royal Society of Chemistry. c) LSV curves of pure and V‐doped MoS₂ NSs. Inset: demonstrated temperature‐dependent resistivity of V‐doped MoS₂ NSs. Reproduced with permission.^{[ 161 ]} Copyright 2014, Royal Society of Chemistry. d) Preparation of hexagonal WS_{2(1− x )}Se_{2 x} through simultaneous selenization and sulfurization reaction of monoclinic WO₃. The room‐temperature PL spectra and the corresponding AFM image of the prepared WS_{2(1− x )}Se_{2 x} NS. e) Comparison for HER catalytic activity for Pt, GC, monolayer WS₂, WSe₂, and WS_{2(1− x )}Se_{2 x} (x = 0.43). f) The corresponding Tafel slope value. d–f) Reproduced with permission.^{[ 157 ]} Copyright 2015, Wiley‐VCH. g) EDS element mapping of a monolayer graphene NS that was partially covered by MoS _x Cl _y . h) HRTEM and local FFT image of a MoS _x Cl _y –VG sheet. g,h) Reproduced with permission.^{[ 72 ]} Copyright 2015, Royal Society of Chemistry. i) HER performance and j) their corresponding Tafel plot of MoS _x Cl _y , MoSe _x Cl _y , MoS₂, and MoSe₂. k) Cross‐sectional and top to down (inset) SEM images of MoS _x Cl _y /Si MPs. l) PEC‐HER performance of MoSe _x Cl _y /Si MPs (squares), MoS _x Cl _y /Si MPs (circles), and Pt/Si MPs (triangles) photocathodes. The experiments were conducted in 0.5 M H₂SO₄ under 1 Sun irradiation. i–l) Reproduced with permission.^{[ 30 ]} Copyright 2015, Wiley‐VCH.