Engineering 2D Materials for Photocatalytic Water-Splitting from a Theoretical Perspective

Abstract

Splitting of water with the help of photocatalysts has gained a strong interest in the scientific community for producing clean energy, thus requiring novel semiconductor materials to achieve high-yield hydrogen production. The emergence of 2D nanoscale materials with remarkable electronic and optical properties has received much attention in this field. Owing to the recent developments in high-end computation and advanced electronic structure theories, first principles studies offer powerful tools to screen photocatalytic systems reliably and efficiently. This review is organized to highlight the essential properties of 2D photocatalysts and the recent advances in the theoretical engineering of 2D materials for the improvement in photocatalytic overall water-splitting. The advancement in the strategies including (i) single-atom catalysts, (ii) defect engineering, (iii) strain engineering, (iv) Janus structures, (v) type-II heterostructures (vi) Z-scheme heterostructures (vii) multilayer configurations (viii) edge-modification in nanoribbons and (ix) the effect of pH in overall water-splitting are summarized to improve the existing problems for a photocatalytic catalytic reaction such as overcoming large overpotential to trigger the water-splitting reactions without using cocatalysts. This review could serve as a bridge between theoretical and experimental research on next-generation 2D photocatalysts.

XSnS3 (X = Ga, In) monolayer semiconductors as photo-catalysts for water splitting: a first principles study

“…Despite the fact that the calculated suitable band gaps and band alignments provide strong evidence for the photocatalytic performance of the proposed 2D materials, we also calculated Gibb's free energy for hydrogen adsorption DG H as a descriptor to trigger the photocatalytic process of hydrogen evolution reaction for the XSnS 3 monolayers. [65][66][67][68][69][70][71] Moreover, the hydrogen adsorption energy DE H for a single hydrogen-atom adsorbed on XSnS 3 (X = Ga and In) surface can be obtained using the formula:…”

“…Despite the fact that the calculated suitable band gaps and band alignments provide strong evidence for the photocatalytic performance of the proposed 2D materials, we also calculated Gibb's free energy for hydrogen adsorption Δ G H as a descriptor to trigger the photocatalytic process of hydrogen evolution reaction for the XSnS 3 monolayers. 65–71 Moreover, the hydrogen adsorption energy Δ E H for a single hydrogen-atom adsorbed on XSnS 3 (X = Ga and In) surface can be obtained using the formula:where, E XSnS 3 +H and E XSnS 3 are the total energies of the proposed monolayers with and without adsorbed H atom on the surface, E (H 2 ) is the energy of hydrogen molecules. Taking into consideration the binding strength of hydrogen, the Gibb's free energy can be calculated as follows:Δ G H = Δ E H + Δ E ZPE − T Δ S H where Δ E H , Δ E ZPE and Δ S H , denotes respectively the hydrogen binding strength, the variation in zero-point energy and the change in entropy of H 2 molecule between the adsorbed and gas-phase state at standard conditions (1 bar of H 2 and pH = 0 at 300 K).…”

Photocatalytic properties of anisotropic β-PtX2 (X = S, Se) and Janus β-PtSSe monolayers

“…To achieve highly efficient photocatalytic water splitting together with significantly reducing environmental and energy concerns, great efforts have been made to explore novel two-dimensional (2D) materials capable of harvesting sunlight with a high solar-to-hydrogen energy conversion efficiency and ability for the separation and migration of photoexcited carriers. 1,2 A variety of novel 2D materials as photocatalysts have been proposed, including PdSe 2 , 3 PdSeO 3 , 4 SiP 2 , 5 β-GeSe, 6 β-SnSe, 6 BeN 2 , 7 GaAs, 8 C 3 S, 9 C 3 N 5 , 10 g-CN, 11 Pd 3 P 2 S 8 , 12 CuCl (1.61 V), 13 AgBiP 2 Se 6 , 14 Ga 2 SSe, 15 Ga 2 S 3 , 16 HfX 3 (X = S, Se), 17 Janus MXY (M = Mo, W; XY = S, Se, Te), 18–20 Janus CrXY (XY = S, Se, Te), 21,22 Janus PdXY(XY = S, Se, Te), 23 Janus M 2 XY (M = Ga, In; XY = S, Se, Te), 24,25 Janus PdPSeX (X = O, S, Te), 26 Janus Pd 4 S 3 Se 3 , 27 and 2D honeycomb polymers. 28,29 However, due to their low energy conversion efficiency and high kinetic overpotential, only a few such 2D materials show good photocatalytic properties for water splitting.…”

Monolayer GaOCl: a novel wide-bandgap 2D material with hole-doping-induced ferromagnetism and multidirectional piezoelectricity

“…5 Owing to their extraordinary optical, mechanical and electronic properties, 2D materials have aroused much interest, and experimental and theoretical studies are devoted to exploring novel 2D systems with excellent properties. 6–9…”

“…5 Owing to their extraordinary optical, mechanical and electronic properties, 2D materials have aroused much interest, and experimental and theoretical studies are devoted to exploring novel 2D systems with excellent properties. [6][7][8][9] Semiconductors with a wide bandgap, such as GaN and SiC, offer an extended functionality of both electronics and optoelectronics, and have been successfully commercialized. With the demand for detecting blue and ultraviolet light in a wide range of civilian and military applications, such as light-emitting diodes, biological analysis, flame detection, etc., 2D materials with a wide bandgap typically exceeding 3 eV have attracted particular attention.…”