Regulating photocatalysis by the oxidation state of titanium in TiO2/TiO

The current research on the CO2RR process mainly focuses on the high selectivity of a single product and the material selectivity in the path process [1],[2] Guo et al., 2019. There are relatively few studies on changes and causes. In this work, TiO2/TiO formed by in-situ oxidation was used as a photocatalyst for CO2 reduction. The structure of this semiconductor/metal-like heterojunction makes the internal electric field appear in the catalyst, which greatly improves the activity of the photocatalytic reaction. During the test, it was found that the hydrogenation product gradually appeared in the reaction product due to the appearance of TiO2. In the absence of a sacrificial agent, the catalyst exhibited a high HCOOH selectivity and obtained a considerable yield of 46.37 mu mol g(-1)h(-1). After adding the sacrificial agent triethanolamine (TEOA), TiO2/TiO showed good CO production ability. As the reaction progressed, CH4 was gradually produced. DFT calculations confirmed that the structure of the heterojunction has lower workfunction for the CO2 hydrogenation option, and the energy band at the contact position is curved. The construction of this system has guiding significance for the construction of light-driven CO2 hydrogenation products in the future. (C) 2022 Elsevier Inc. All rights reserved.