Pt Atom-Substituted MoC Single-Atom Catalyst for Enhancing H2 Production

Single-atom catalysts with a maximum atom utilization efficiency have shown great potential for application in energy conversion and storage fields. Herein, a highly stable single-atom Pt catalyst (Pt-1/alpha-MoC) on alpha-MoC nanoribbons with Pt loading up to 2% is fabricated using an atom substitution strategy for the water-gas shift (WGS) reaction, which exhibits a very high H-2 production rate of 1094 mu mol(CO)/g(cat)s at 200 degrees C, indicating one of the highest activity levels compared with the reported state-of-the-art WGS catalysts. Complementary advanced characterizations, including aberration-corrected scanning transmission electron microscopy (STEM), synchrotron X-ray absorption spectroscopy (XAS), and density functional theory (DFT) calculations, demonstrate that single Pt atoms are uniformly dispersed on the outermost surface of alpha-MoC and strongly confined within the crystalline lattice of molybdenum carbides. In situ spectroscopic studies and DFT calculations reveal that the Pt-MoC interface serves as a primary active site of the water gas shift (WGS) reaction, boosting H2O molecule activation, to form the key OH* intermediates. Our findings offer an efficient method for the rational design of high-activity single-atom catalysts and lay a good foundation for their industrial application.