A confined thermal transformation strategy to synthesize single atom catalysts supported on nitrogen-doped mesoporous carbon nanospheres for selective hydrogenation

Carbon-supported single-atom catalysts (SACs) have brought considerable attention in heterogeneous catalysis, which, however, often suffer from low activity due to the mass transfer limitation. Herein, we report a soft-templating method to synthesize the core−shell mesostructured polymer nanospheres with metal nanoclusters (M-NCs, M=Pd, Pt) as the core, which can be easily converted into the nitrogen-doped mesoporous carbon nanospheres (NMCS) supported SACs (M1/NMCS) after a confined thermal transformation process. By this strategy, Pd1/NMCS and Pt1/NMCS are successfully prepared with rich porosity and high N content. The abundant N species in M1/NMCS can be employed as anchoring sites to capture and stabilize the single metal atoms. In addition, the mesoporous structure of M1/NMCS is beneficial for the mass transfer and the exposure of active sites. Benefiting from such a unique structure, the as-obtained Pd1/NMCS exhibits excellent activity, selectivity, and long-term stability in the selective hydrogenation of quinoline.