Sulfur‐Deficient ZnIn₂S₄/Oxygen‐Deficient WO₃ Hybrids with Carbon Layer Bridges as a Novel Photothermal/Photocatalytic Integrated System for Z‐Scheme Overall Water Splitting

Abstract

Although photocatalytic overall water splitting is a potential technology for converting solar energy into chemical fuel, the widely reported solar‐to‐hydrogen efficiency is around 1%, indicating unsatisfactory photocatalytic performance. Here, a novel photocatalyst material is designed and a whole reaction system is constructed, resulting in an integrative photothermal–photocatalytic Z‐scheme overall water splitting reaction system. In terms of materials design, a novel sulfur‐deficient ZnIn2S4/oxygen‐deficient WO3 (ZIS–WO) hybrid with surface‐carbonized wood (C‐wood) is reported. The ZIS–WO hybrid with sulfur and oxygen vacancies promotes the adsorption of visible light and the separation of charge carriers. The conductive C‐wood is strategically used as an additional electron bridge to accelerate electron transfer. In terms of system construction, the C‐wood exploits the photothermal effect to change the solid/liquid/gas triphase system to a solid/gas biphase system by transforming liquid water into steam, which drastically restrains carrier recombination, and decreases the photocatalytic reaction barrier. The H2 and O2 production rates in the proposed system are approximately 169.2 and 82.5 µmol h–1 under air mass (AM) 1.5 light irradiation, and the corresponding solar‐to‐hydrogen efficiency is as high as 1.52%. The study from photocatalyst design to reaction system construct opens a new insight for versatile and high‐performance photocatalytic overall water splitting.

Thermo-photo catalysis: a whole greater than the sum of its parts

“…The explored light-absorption substrates range from synthetic materials such as black silicon, 102,107,178 Fe 3 Si aerogel, 179 and Cr film, 180 to biomass such as surface-charred wood. 41,181 Furthermore, photo-thermal substrate can be coupled with a pyroelectric substrate, which allows the generation of pyroelectric field around the catalyst. 182 As-induced pyroelectric field can guide the migration direction of photo-generated charge carriers, thus promoting their separation, extending their lifetime, and achieving high catalytic efficiencies.…”

Shining light on ZnIn2S4 photocatalysts: Promotional effects of surface and heterostructure engineering toward artificial photosynthesis

“…Notably, the photosynthesis in plants generally assembles the Z‐scheme photocatalytic systems, thus advancing the potential of the artificial heterogeneous Z‐scheme photocatalysis to make photocatalysis applicable in future industrial applications 308 . Herein, to get one step closer to the commercialized production, the integrative photothermal‐photocatalytic system as proposed by Li's and Ho's teams could be further studied for the exploitation of photothermal effect in lowering the photocatalytic reaction barrier 248,309 . In short, there is a need for future researchers to develop improved synthesis methods that yield ZnIn 2 S 4 with larger surface area and enhanced crystallinity without severe aggregation in an environmentally benign manner while looking forward to Z‐scheme ZnIn 2 S 4 ‐based photocatalysts for large‐scale fabrication.…”

A Dual‐Channel Charge Transfer Heterostructure toward Boosting Photocatalytic Hydrogen Evolution

“…As expected, the PL intensities of Co 9 S 8 extremely decrease after coupling with CdIn 2 S 4 (Figure 3a), indicating the introduction of CdIn 2 S 4 promotes the photoinduced charge carriers transfer. [37][38][39] Additionally, the PL intensity of 12%-Co 9 S 8 /CdIn 2 S 4 is the lowest among the three Co 9 S 8 /CdIn 2 S 4 composites, suggesting that the ingredient ratio is favorable for charge transfer. It is exciting that the Co 9 S 8 / CdIn 2 S 4 /Pt nanocages exhibit the lowest PL intensity in all as-prepared catalysts, suggesting the carrier recombination can be effectively suppressed.…”