Electronic Metal–Support Interaction at ZnO _<i>x</i> /Cu Interface Enhances H ₂ Production in Methanol Steam Reforming

Methanol steam reforming (MSR) is a promising technology for in situ hydrogen production, while the mechanistic role of zinc in the widely used Cu/ZnO/Al 2 O 3 catalyst remains ambiguous. Electronic metal–support interactions (EMSIs) are generally applied for modulating active sites in such heterogeneous catalysts, offering opportunities to optimize energy conversion processes. Here, we revealed that a dynamic EMSI between Cu and ZnO enhances catalytic performance by constructing ZnO x /Cu interfaces, facilitating bidirectional electron transfer between ZnO x and Cu. The electron transfer from ZnO x to Cu mitigates overoxidation of Cu 0 to Cu + during water activation, thereby improving water activation efficiency, while the electron transfer back to ZnO x accelerates the reduction of Cu + back to Cu 0, promoting dehydrogenation of reactive formate at the ZnO x /Cu interface, the rate-determining step at low temperatures. Thus, we establish a dual role for the EMSI-induced ZnO x /Cu interface in stabilizing active intermediates and facilitating redox cycling. These findings provide insights into the precise regulation of catalytic active sites via EMSI engineering, offering guidance for high-efficiency catalysts design for sustainable energy conversion.