High-Efficiency Water Gas Shift Reaction Catalysis on α-MoC Promoted by Single-Atom Ir Species

Single-atom catalysts (SACs) with complete dispersion of metal species on substrates provide the ultimate atom economy and opportunities for improved heterogenous catalysis or to develop more catalyst formulation. However, atomically dispersed dopants can also improve the catalyst in an indirect capacity. Here, we report an Ir1/α-MoC SAC that exhibits high activity for water gas shift reaction with ∼100% CO conversion at 150 °C. The reaction rate of this catalyst is orders of magnitude higher than previous Ir-based catalysts and ∼4 times that of α-MoC. Experimental characterizations combined with density functional theory (DFT) calculations reveal that such good performance originates from the effective catalysis by the α-MoC substrate with Ir1 serving as a single-atom promoter. DFT calculations also establish a correlation between the active Mo sites and the catalytic performance for water gas shift reaction. This work highlights the possibility of enhancing catalysis by single-atom promoters as a promising strategy for designing effective SACs.