In situ Irradiated XPS Investigation on S‐Scheme TiO2@ZnIn2S4 Photocatalyst for Efficient Photocatalytic CO2 Reduction

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 17; no. 41
• Main Authors: Wang, Libo, Cheng, Bei, Zhang, Liuyang, Yu, Jiaguo
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-10-2021
• Subjects: Carbon dioxide; Charge transfer; Conversion; core‐shell; Current carriers; Electron paramagnetic resonance; Heterojunctions; hollow structures; Nanotechnology; Photocatalysis; Photocatalysts; Photoelectrons; Reduction; step‐scheme heterojunction; S‐scheme mechanism; Titanium dioxide; Work functions
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202103447

Reasonable design of efficient hierarchical photocatalysts has gained significant attention. Herein, a step‐scheme (S‐scheme) core‐shell TiO2@ZnIn2S4 heterojunction is designed for photocatalytic CO2 reduction. The optimized sample exhibits much higher CO2 photoreduction conversion rates (the sum yield of CO, CH3OH, and CH4) than the blank control, i.e., ZnIn2S4 and TiO2. The improved photocatalytic performance can be attributed to the inhibited recombination of photogenerated charge carriers induced by S‐scheme heterojunction. The improvement is also attributed to the large specific surface areas and abundant active sites. Meanwhile, S‐scheme photogenerated charge transfer mechanism is testified by in situ irradiated X‐ray photoelectron spectroscopy, work function calculation, and electron paramagnetic resonance measurements. This work provides an effective strategy for designing highly efficient heterojunction photocatalysts for conversion of solar fuels.
Hierarchical S‐scheme TiO2@ZnIn2S4 core‐shell hollow spheres heterojunction is successfully fabricated by growing ZnIn2S4 nanosheets on the outer surface of TiO2 hollow spheres. Experimental results demonstrate that this rational design can not only effectively facilitate the separation of useful photogenerated electrons and holes, but also provide large surface areas and abundant active sites for multi‐electron photocatalytic CO2 reduction reaction.