Fig. 4: Catalytic performance of Pd3ZnCx in acetylene selective hydrogenation reaction.

Acetylene conversion (bar plot) and ethylene selectivity (line plot) of the Pd3ZnCx (red) and PdZn (black) catalysts in selective hydrogenation of acetylene in an excess of ethylene, with different H2/C2H2 ratio. a 2% C2H2, 2.2% H2 and 80% C2H4 in balance with He (H2/C2H2 = 1); b 2% C2H2, 8% H2 and 80% C2H4 in balance with He (H2/C2H2 = 4). Reaction conditions: space velocity = 5000 mL g−1 h−1; pressure = 0.5 MPa. c Durability test on Pd3ZnCx for 200 h at 120 °C, and STEM images after the durability test as inset. Pd loading: 0.08 wt%. Feed gas: 2% C2H2, 2.2% H2 and 80% C2H4 in balance with He. Reaction conditions: space velocity = 5000 mL g−1 h−1; pressure = 0.5 MPa. d Catalytic performance of Pd3ZnCx and other reported transition metal catalysts in literatures for the semi-hydrogenation of acetylene (Data from Table S4). e DFT calculated surface model of PdZn and Pd3ZnCx (top view). f Free energy profiles of acetylene hydrogenation on PdZn and Pd3ZnCx catalysts.