Phase Transformation-Driven Strong Metal–Support Interaction Shifting CO ₂ Methanation to Reverse Water–Gas Shift Reaction on Ru/ZrO ₂ Catalysts

Strong metal–support interaction (SMSI), in which the oxide support migrates onto the surface of the supported metal nanoparticle and thereby alters the product distribution, typically occurs with reducible oxides. Here, we report a phase-transformation-induced SMSI on nonreducible ZrO2-supported Ru catalysts, leading to the formation of an amorphous ZrO2 overlayer on Ru particles and shifting product selectivity from CH4 to CO. Operando DRIFTS experiments and kinetic modeling reveal that a shared formate (HCOO*) intermediate is competitively consumed by both CO2 methanation and the reverse water–gas shift (RWGS) reaction. At the initial stage, the rate of HCOO* decomposition to CO* is lower than that of CO* hydrogenation, leading to the formation of CH4. Upon surface reconstruction, however, the rate of HCOO* decomposition surpasses that of CO* hydrogenation, resulting in CO-selective output. This study not only extends the understanding of SMSI in heterogeneous catalysis but also provides mechanistic insights into the dynamic evolution of product distribution.