Probing the roles of S atom and nanoparticle size over different sizes of S-modified Cu and Pd nanoparticles in regulating catalytic performance of acetylene Semi-hydrogenation

To reveal the influences of S atom and nanoparticle size in the S-modified Cu and Pd (Cu-S and Pd-S) nanoparticle catalysts on C2H2 semi-hydrogenation performance, the S-modified Mn (M = Cu and Pd, n = 13, 38, 55) catalysts and the periodic M(1 1 1) surface representing much larger size of nanoparticle were constructed to examine C2H2 semi-hydrogenation. The results showed that C2H4 selectivity over Cu-S catalysts is higher than that over Pd-S catalysts, while C2H4 formation rate is lower over Cu-S catalysts. Compared with the pure M catalysts, the S-modified M catalysts enhance C2H4 selectivity due to the geometric and electronic effects. The screened larger nanoparticle size of Cu(1 1 1)-S catalyst is more suitable for C2H2 semi-hydrogenation. Hence, the electronic and geometric effects of S-modified metal catalysts can be controlled by tuning the nanoparticle size and spatial scale of active site induced by S atoms, then, the catalytic performance of C2H2 semi-hydrogenation could be regulated.