Regulating the Interfacial Synergy of Ni/Ga2O3 for CO2 Hydrogenation toward the Reverse Water–Gas Shift Reaction

The reverse water–gas shift (RWGS) reaction is a critical step for adjusting the CO/H2 ratio in crude syngas via CO2 hydrogenation in the chemical industry. Generally, the conditioning of syngas competitively occurs in two different reaction pathways at a moderate temperature range (350–450 °C), such as RWGS (CO2 + H2 → CO + H2O) and methanation (CO2 + 4H2 → CH4 + 2H2O). In this study, we demonstrate that the interfacial synergy of Ni/Ga2O3 can boost selective CO2 hydrogenation to CO (CO selectivity >95%) in the temperature range of 350–450 °C. Detailed investigations indicate that the interfacial synergy of the Ni/Ga2O3 interface significantly influences the adsorption of H2 and CO2 and thus leads to the formation of different intermediates and products. In particular, *HCOO is preferentially formed on the Ni surface, which is further hydrogenated into CH4 and H2O. By contrast, the Ni/Ga2O3 interface favors the formation of CO with the assistance of H2. This study not only provides a highly selective catalyst for the RWGS reaction during CO2 hydrogenation but also promotes research on surface modification of catalysts for enhanced activity and selectivity.