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Solar photocatalytic H2 production has drawn an increasing amount of attention from the scientific community, industry, and society due to its use of green solar energy and a photocatalyst (semiconductor material) to produce green H2. Cu-based semiconductors are interesting as photocatalysts for H2 production because Cu is earth-abundant, cheap, and the synthesis of its copper-containing semiconductors is straightforward. Moreover, Cu-based semiconductors absorb visible light and present an adequate redox potential to perform water splitting reaction. Nevertheless, pristine Cu-based semiconductors exhibit low photoactivity due to the rapid recombination of photo-induced electron-hole (e−-h+) pairs and are subject to photo corrosion. To remedy these pitfalls, the Cu semiconductor-based Z-scheme family (Z-schemes and S-schemes) presents great interest due to the charge carrier mechanism involved. Due to the interest of Z-scheme photocatalysts in this issue, the basic concepts of the Z-scheme focusing on Cu-based semiconductors are addressed to obtain novel systems with high H2 photo-catalytic activity. Focusing on H2 production using Cu-based Z-schemes photocatalyst, the most representative examples are included in the main text. To conclude, an outlook on the future challenges of this topic is addressed. [ABSTRACT FROM AUTHOR]

A theoretical study is conducted with three MX3$_{3}$ monolayer 2D materials (AlI3$_{3}$, AsI3$_{3}$, and IrBr3$_{3}$) on their electronic properties and how a halogen monovacancy affects their thermostability. Density functional theory (DFT) calculations are run to obtain the band structures and phonon dispersions for both pristine and defective structures. It is shown that AlI3$_{3}$ and AsI3$_{3}$ have indirect bandgaps of 2.40$2.40$ and 2.23$2.23$ eV, respectively. IrBr3$_{3}$ has a direct bandgap of 1.65$1.65$ eV. Phonon dispersions indicate that they are all thermodynamically stable in pristine state, but their defective counterparts are not. Ab‐initio molecular dynamics (AIMD) simulations are conducted for defective ones to further investigate their stability. It is found that AlI3 and AsI3 layers are decomposed while IrBr3 layer is bent. Further investigations are conducted by analyzing the bond energies and bond lengths of the three materials. It shows that AlI3$_{3}$ and AsI3$_{3}$ have lower bond energy and longer bond length, which makes them dissociated at the ambient temperature while higher bond energy and shorter bond length keep IrBr3$_{3}$ stabilized and enable its displacive phase transition in displacive limit. [ABSTRACT FROM AUTHOR]

A theoretical study is conducted with three MX3$_{3}$ monolayer 2D materials (AlI3$_{3}$, AsI3$_{3}$, and IrBr3$_{3}$) on their electronic properties and how a halogen monovacancy affects their thermostability. Density functional theory (DFT) calculations are run to obtain the band structures and phonon dispersions for both pristine and defective structures. It is shown that AlI3$_{3}$ and AsI3$_{3}$ have indirect bandgaps of 2.40$2.40$ and 2.23$2.23$ eV, respectively. IrBr3$_{3}$ has a direct bandgap of 1.65$1.65$ eV. Phonon dispersions indicate that they are all thermodynamically stable in pristine state, but their defective counterparts are not. Ab‐initio molecular dynamics (AIMD) simulations are conducted for defective ones to further investigate their stability. It is found that AlI3 and AsI3 layers are decomposed while IrBr3 layer is bent. Further investigations are conducted by analyzing the bond energies and bond lengths of the three materials. It shows that AlI3$_{3}$ and AsI3$_{3}$ have lower bond energy and longer bond length, which makes them dissociated at the ambient temperature while higher bond energy and shorter bond length keep IrBr3$_{3}$ stabilized and enable its displacive phase transition in displacive limit. [ABSTRACT FROM AUTHOR]