Nitrogen-fixing of ultrasmall Pd-based bimetallic nanoclusters on carbon supports

Abstract

Synthesis of supported Pd-based bimetallic catalysts is of great importance in the heterogeneous catalysis field owing to their optimal geometric and electronic effects. Downsizing active metals to ultrasmall nanocluster (<2 nm), which is mandatory for maximizing the metal atom utilization, however remains as formidable synthesis challenges. Here, we present a general synthetic approach to sub-2 nm Pd-based bimetallic nanoclusters on porous nitrogen-doped carbon supports, in which the strong chemical interaction between metal and nitrogen largely suppresses the metal aggregation during the H2-reduction at 400–500 °C. Through the nitrogen-fixing strategy, we prepare 9 sub-2 nm Pd-based bimetallic nanocluster catalysts by conventional impregnation process. The prepared supported bimetallic Pd-Pb nanocluster catalyst exhibit a high turnover frequency of 1092 h−1 for the semihydrogenation of phenylacetylene under a mild condition (30 °C, 5 bar H2), along with a high selectivity of >93% to styrene, demonstrating the alloying and small-size effects in the bimetallic nanocluster catalysts.