Non-noble transition metals Mo and Cr doping greatly enhances the basal-plane catalytic activity of two-dimensional 1T′-ReS₂ for hydrogen evolution reaction as comparable with those of Pt-doping.

The electronic structure, magnetic properties and stability of transition-metal (TM) doped armchair MoS₂ nanoribbons (AMoS₂NRs) with full hydrogen passivation have been investigated using density functional theory.

We performed density functional theory calculations to investigate the electronic structure of armchair MoS ₂ nanoribbons (AMoS ₂ NRs) with and without passivation. The AMoS ₂ NRs are nonmagnetic semiconductors and there exists a transition from indirect to direct band gap with the increasing of ribbon widths. Their electronic structures are determined by edge states. Edge passivation is an effective way to engineer the band structure of AMoS ₂ NRs because it can vary the edge charge distribution. By choosing passivated groups and controlling passivated patterns, we can also tune the band gap of AMoS ₂ NRs from indirect to direct. As a result, full hydrogen (H) or amidogen (NH ₂ ) passivation and partial hydroxyl (OH) passivation can not only tune AMoS ₂ NRs from the indirect to direct band gap semiconductors, but also enhance the stability of the systems. Our interesting findings on indirect–direct band gap tuning may be helpful for engineering the band structure of AMoS ₂ NRs and open the possibility of their application in optoelectronics.

An oxygen-vacancy-induced internal electric field enhances the photocatalytic hydrogen production activity of a BiVO₄ [110] facet.

Cost-efficient bifunctional electrocatalysts with good stability and high activity are in great demand to replace noble-metal-based catalysts for overall water-splitting. Ni₃S₂ has been considered a suitable electrocatalyst for either the hydrogen evolution reaction (HER) or the oxygen evolution reaction (OER) owing to its good conductivity and stability, but high performance remains a challenge. Based on density functional theory calculations, we propose a practical 3d-transition-metal (TM = Mn, Fe and Co) doping to enhance the catalytic performance for both HER and OER on the Ni₃S₂ (101) facet. The enhancement originates from TM-doping-induced charge rearrangement and charge transfer, which increases the surface activity and promotes catalytic behavior. In particular, Mn-doped Ni₃S₂ shows good bifunctional catalytic activity because it possesses more active sites, reduced hydrogen adsorption free energy (ΔG_H*) for HER and low overpotential for OER. Importantly, this work not only provides a feasible means to design efficient bifunctional electrocatalysts for overall water-splitting but also provides insights into the mechanism of improving catalytic behavior.

This work proposes applying the strain and electric filed to engineer the band structure of 2D ReS₂ and enhance its photocatalytic activity for hydrogen production through water-splitting.