Anti-sintering Ni-ZnO catalyst stabilized by a dual protection of SMSI and carbon for efficient RWGS reaction

Colloidal nanoparticles with uniform particle size distribution, tailored exposed facets, and controllable compositions appealed to broad interests in heterogeneous catalysis. Nevertheless, due to the strong attachment of capping agents to the nanoparticles, cleaning the nanoparticle surface without changing the size of nanoparticles remains a significant challenge. Herein, based on the double confinement of the strong metal-support interaction (SMSI) effect and carbon encapsulation, the well-stabilized Ni-ZnO-S3 catalyst was successfully synthesized. The size of Ni nanoparticles after calcination in the sequence of H2-N2 mixture, air, and H2-N2 mixture remained below 5 nm. Due to no significant size change in Ni nanoparticles, the prepared Ni-ZnO-S3 catalyst served well as model catalysts in the RWGS reaction, where the CO2 conversion and CO yield increased proportionally to the Ni loading weight. According to the result of in-situ FTIR, an associative mechanism of RWGS reaction over Ni-ZnO-S3 was also identified. Therefore, this dual protect strategy provides a potential solution for building highly anti-sintering catalysts based on the colloidal synthesis route.