Rational Control of Oxygen Vacancy Density in In 2 O 3 to Boost Methanol Synthesis from CO 2 Hydrogenation

作者：Wenhang Wang, Kaixuan Huo, Yang Wang, Jinghao Xie, Xu Sun, Yingluo He, Meng Li, Jie Liang, Xinhua Gao, Guohui Yang, Simin Lin, Fengliang Cao, Hu Jiang, Mingbo Wu, Noritatsu Tsubaki · 发表于：ACS Catalysis · 年份：2024 · DOI：10.1021/acscatal.4c01929 · 被引用次数：76 · 研究领域：Catalytic Processes in Materials Science、Metal-Organic Frameworks: Synthesis and Applications、Catalysts for Methane Reforming

Oxygen vacancies (O v ) in reducible metal oxides are the vital active sites for methanol synthesis via a CO 2 hydrogenation technology. However, the relationship between the density of O v and the methanol synthesis performance is still ambiguous, and it still shows a lack of a versatile strategy to precisely tailor the number of O v . In this study, with In 2 O 3 as a representatively catalytic component, the density functional theory computation confirms that the O v property, especially O v density, is pivotal to enhancing methanol selectivity of CO 2 hydrogenation by suppressing the undesirable reverse water–gas shift reaction for CO formation, which is attributed to the unique electronic density of In atoms around O v . To verify the theoretical results, we report a protocol to optimize the concentration of O v on In 2 O 3 by sequential carbonization and oxidation (SCO) treatments of In-based metal–organic frameworks, during which the consumption of carbon species and the structural reconstruction of the In 2 O 3 crystal regulated the particle size and O v concentration of In 2 O 3 by varying the oxidation temperature. The In 2 O 3 -5 catalyst carbonized and oxidized at 500 °C exhibits good methanol selectivity (72.3%) at a CO 2 conversion of 9.9% under 330 °C, 3 MPa, and high space velocity of 12,000 L –1 kg cat –1 h –1 . Multiple in situ characterizations clarify that the proposed O v property regulating the SCO strategy is convenient to boost methanol synthesis by al...