Revealing the effect of metal-support interactions at the Ni/In2O3(111) interface on the selective CO2 hydrogenation

In2O3-supported Ni catalysts exhibit remarkable catalytic activity and selectivity in CO2 hydrogenation to methanol, but the underlying mechanisms and metal-oxide interactions during the reaction remain elusive. Herein, we investigate the Ni-In2O3 interaction by physical vapor deposition of Ni onto well-defined In2O3(111) thin films. In-situ near ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) was employed to probe the CO2 hydrogenation processes on these Ni/In2O3(111) model systems. Our results reveal that the small Ni clusters supported on the In2O3(111) surface at low Ni coverages exhibit cationic states. The chemical bonding and associated electron transfer at the Ni/In2O3(111) interface play crucial roles in the activation of H2 and CO2. Importantly, reaction intermediates (CO3*, OH, and HCOO*) are readily formed and desorbed under CO2 hydrogenation conditions. Our study highlights the significance of metal-support interactions on the selectivity of CO2 hydrogenation. These findings provide valuable insights into the rational design of advanced In2O3-based catalysts for CO2 hydrogenation.