Confinement-Induced Indium Oxide Nanolayers Formed on Oxide Support for Enhanced CO<sub>2</sub> Hydrogenation Reaction
Jianyang Wang, Rongtan Li, Guanghui Zhang, Cui Dong, Yamei Fan, Shuangli Yang, Mingshu Chen, Xinwen Guo, Rentao Mu, Yanxiao Ning, Mingrun Li, Qiang Fu, Xinhe Bao
Abstract
An enclosed nanospace often shows a significant confinement effect on chemistry within its inner cavity, while whether an open space can have this effect remains elusive. Here, we show that the open surface of TiO 2 creates a confined environment for In 2 O 3 which drives spontaneous transformation of free In 2 O 3 nanoparticles in physical contact with TiO 2 nanoparticles into In oxide (InO x ) nanolayers covering onto the TiO 2 surface during CO 2 hydrogenation to CO. The formed InO x nanolayers are easy to create surface oxygen vacancies but are against over-reduction to metallic In in the H 2 -rich atmospheres, which thus show significantly enhanced activity and stability in comparison with the pure In 2 O 3 catalyst. The formation of interfacial In–O–Ti bonding is identified to drive the In 2 O 3 dispersion and stabilize the metastable InO x layers. The InO x overlayers with distinct chemistry from their free counterpart can be confined on various oxide surfaces, demonstrating the important confinement effect at oxide/oxide interfaces.