Tracking Dynamics of Supported Indium Oxide Catalysts in CO<sub>2</sub> Hydrogenation to Methanol by In Situ TEM
Henrik Eliasson, Y. Chiang, Thaylan Pinheiro Araújo, Xiansheng Li, Rolf Erni, Sharon Mitchell, Javier Pérez‐Ramírez
Abstract
Abstract Supported reducible oxides, such as indium oxide on monoclinic zirconia (In 2 O 3 /m‐ZrO 2 ), are promising catalysts for green methanol synthesis via CO 2 hydrogenation. Growing evidence suggests that dynamic restructuring under reaction conditions plays a crucial but poorly understood role in catalytic performance. To address this, the direct visualization of the state‐of‐the‐art In 2 O 3 /m‐ZrO 2 catalyst under CO 2 hydrogenation conditions ( T = 553 K, P = 1.9 bar, CO 2 :H 2 = 1:4) is pioneered using in situ scanning transmission electron microscopy (STEM), comparing its behavior to In 2 O 3 on supports with similar (tetragonal, t‐ZrO 2 or anatase TiO 2 ) or lower (LSm‐ZrO 2 ) surface areas. Complementary in situ infrared spectroscopy and catalytic tests confirm methanol formation under equivalent conditions. A machine‐learning‐based difference imaging approach differentiates and ranks restructuring patterns, revealing that partially reduced InO x species on m‐ZrO 2 undergo cyclic aggregation‐redispersion via atomic surface migration, maintaining high active phase dispersion. High‐resolution ex situ STEM analysis further shows the epitaxial formation of In 2 O 3 mono‐ and bilayers on (100) m‐ZrO 2 facets, highlighting strong oxide‐support interactions. In contrast, sintering prevails on t‐ZrO 2 , a‐TiO 2 , and low‐surface m‐ZrO 2 , correlating with lower methanol productivity. This work underscores the pivotal role of oxide‐support interfacial interactions in the reaction‐induced restructuring of InO x species and establishes a framework for tracking nanoscale catalyst dynamics.