Carbide-Supported Au Catalysts for Water–Gas Shift Reactions: A New Territory for the Strong Metal–Support Interaction Effect

Strong metal–support interaction (SMSI) has been regarded as one of the most important concepts in heterogeneous catalysis, which has been almost exclusively discussed in metal/oxide catalysts. Here, we show that gold/molybdenum carbide (Au/MoCx) catalysts feature highly dispersed Au overlayers, strong interfacial charge transfer between metal and support, and excellent activity in the low-temperature water–gas shift reaction (LT-WGSR), demonstrating the active SMSI state. Subsequent oxidation treatment results in strong aggregation of Au nanoparticles, weak interfacial electronic interaction, and poor LT-WGSR activity. The two interface states can be transformed into each other by alternative carbonization and oxidation treatments. This work reveals the active SMSI effect in metal/carbide catalysts induced by carbonization, which opens a new territory for this important concept