Enhanced Hydrogen Adsorption on In2O3(111) via Oxygen Vacancy Engineering

• Published in: Precision Chemistry Vol. 3; no. 6; pp. 337 - 347
• Main Authors: Ding, Yishui, Chen, Jie, Zheng, Haihong, Jiang, Yalong, Li, Linbo, Geng, Xiangrui, Lian, Xu, Yang, Lu, Zhang, Ziqi, Zhang, Kelvin Hongliang, Li, Hexing, Zhong, JianQiang, Chen, Wei
• Format: Journal Article
• Language: English
• Published: University of Science and Technology of China and American Chemical Society 23.06.2025; American Chemical Society
• Subjects: indium oxide; H2 dissociation; surface chemistry; in situ NAP-XPS; oxygen vacancies
• ISSN: 2771-9316; 2771-9316
• DOI: 10.1021/prechem.5c00005

The emergence of In2O3 as an efficient catalyst for selective hydrogenation has attracted significant attention. However, the mechanism of hydrogen (H2) dissociation on In2O3 remains experimentally elusive. In this work, we show that the interaction of H2 with In2O3 is strongly influenced by the presence of oxygen vacancies. Using a combination of in situ near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS), ultraviolet photoelectron spectroscopy (UPS), infrared reflection absorption spectroscopy (IRRAS), and density functional theory (DFT) calculations, we systematically investigated the interaction of H2 on well-defined oxidized In2O3(111) and partially reduced In2O3–x (111) surfaces. Our results reveal that H2 dissociates and adsorbs as hydroxyl groups (OH), which are exclusively stabilized on the In2O3–x (111) surface. The adsorbed hydrogen species act as electron donors, contributing to interfacial electron accumulation near the surface and inducing downward band bending. DFT calculations further indicate that oxygen vacancies in In2O3–x (111) are critical for facilitating the heterolytic dissociation of H2, leading to the stabilization of In–H and OH species. These findings provide valuable implications for the catalytic behavior of indium oxide in hydrogenation and hydrogen-involved redox reactions.