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Utilizing photocatalytic method to produce hydrogen by splitting water is an efficient strategy to solve the hotspot issues of energy crisis and environmental pollution. Herein, we systematically investigate the corresponding properties of the reported Cu‐bearing ternary compound monolayer CuP2Se by using the first‐principle calculations. The monolayer CuP2Se has quite small cleavage energy of 0.51 J/m2, indicating it can be easily produced by the mechanical exfoliation method experimentally. In addition, it is an indirect bandgap semiconductor material which has a moderate value of 1.91 eV. The conduction band minimum (CBM) and valence band maximum (VBM) can perfectly straddle the redox potentials of water when a biaxial strain of −4% to 4% is applied, unveiling the high photocatalytic thermodynamic stability of monolayer CuP2Se in response to the effect of solvent tension. Remarkably, the monolayer CuP2Se also demonstrates significant sunlight capturing ability in the visible region. The outstanding electronic and optical properties suggest that the monolayer CuP2Se is undoubtedly a viable material for photocatalytic water splitting. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials with intrinsic electric fields (EF) are considered promising photocatalysts for hydrogen production from water splitting, but are still restricted by the solar-to-hydrogen (STH) efficiency. Here, we designed and investigated the derived 2D MNX3 and MNXY2 (M, N = In/Ga/Al; X, Y = S/Se/Te) monolayers as potential photocatalysts for water splitting applications. The light absorption of most MNX3/MNXY2 derivatives is significantly enhanced compared with their parent M2X3 monolayers. The introduction of Te with more diffuse valence orbitals than S/Se can effectively reduce the band gap of the MNX3/MNXY2 derivatives, enhancing their light absorption abilities. Some 2D MNX3 and MNXY2 monolayers with STH efficiencies ≥20% are further screened. Interestingly, driven by vacancy defects, the GaAlSSe2-β monolayer can achieve the overall water-splitting process purely by the photoexcited carriers without the need for cocatalysts. Our work provides a prospective strategy for designing new highly efficient photocatalysts for water splitting applications based on the available parent materials by modulating the synergistic relation of bandgap, intrinsic EF, and overpotential. [ABSTRACT FROM AUTHOR]

Strain engineering has been widely used in the study of two‐dimensional semiconductors in recent years, because it can improve catalytic performance by changing the structural characteristics of materials. In this work, we systematically investigate the effects of biaxial strain on the electronic structure, band‐edge positions, and optical absorption of perfect Janus In2S2X (X=Se, Te) particles and vacancy In2S2X (V‐In2S2X). Biaxial strain enables In2S2X to achieve a transition between indirect and direct band gaps. Tensile strain reduces the band‐edge potential of the conduction band minimum (CBM), but compressive strain increases it and then tends to stabilize the material. In V‐In2S2X, the tensile strain makes the top bands of the bandgap overlap with the CBM and moves the bottom band of the bandgap down, reducing the bandgap, which makes the light absorption range redshift. Most importantly, we demonstrate that V‐In2S2X obtains excellent photocatalytic CO2 reduction performance under 4 % tensile strain, broadening its practical applications in many fields. [ABSTRACT FROM AUTHOR]

Efficient catalysts for the electroreduction of N 2 to NH 3 are of paramount importance for sustainable ammonia production. Recently, it was reported that NbSe 2 nanosheets exhibit an excellent catalytic activity for nitrogen reduction under ambient conditions. However, existing theoretical calculations suggested an overpotential over 3.0 V, which is too high to interpret the experimental observations. To reveal the underlying mechanism of the high catalytic activity, in this work, we assessed NbSe 2 edges with different chirality and Se vacancies by using first principles calculations. Our results show that N 2 can be efficiently reduced to NH 3 on a pristine zigzag edge via the enzymatic pathway with an overpotential of 0.45 V. Electronic structure analysis demonstrates that the N 2 molecule is activated by the back-donation mechanism. The efficient tuning of the local chemical environments by edge chirality provides a promising approach for catalyst design., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)