Insights into thermally assisted photocatalytic overall water splitting over ZnTi-LDH in a gas-solid reaction system

• Published in: Catalysis science & technology 2022-10, Vol.12 (21), p.6398-644
• Main Authors: Xiaoning, Wang, Haowen, Chen, Kang, Wang, Xitao, Wang
• Format: Article
• Language: English
• Subjects: Carrier density; Catalytic activity; Gas-solid reactions; Hydrogen production; Hydroxyl groups; Oxygen evolution reactions; Photocatalysis; Photoelectric effect; Water splitting
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/d2cy01175a

In this work, the effects of heating on photocatalytic overall water splitting over ZnTi-LDH were investigated. The results showed that the photocatalytic H 2 production rate increased up to 8 times when the reaction temperature increased from 150 °C to 250 C, demonstrating the significant influence of temperature on the photocatalytic activity. The UV-vis DRS, photocurrent response, EIS and Mott-Schottky results at different temperatures revealed that the heat can improve the absorption of visible light by narrowing the bandgap, increase the concentration of carriers, and promote the effective separation of photogenerated electrons and holes, thus resulting in the enhancement of photocatalytic performance. In addition, in situ FTIR analysis showed that the increase of temperature can accelerate the formation of surface peroxide hydrogen species and bridge hydroxyl groups to enhance the surface photocatalytic oxygen evolution reaction (OER), improving the photocatalytic efficiency. H 2 O 2 and bridge hydroxyl groups form because of water splitting. This process occurs intensely with the addition of heat, resulting in generation of more intermediates. Meanwhile, the separation of electrons and holes is accelerated by the heat.