Matching Relationship Between Carbon Material and Pd Precursor

The matching relationship between carbon material and Pd precursor was investigated by constructing Pd@C catalysts with four carbon materials (mesoporous carbon, activated carbon, N-doped carbon and O-doped carbon) and three Pd precursors (PdCl2, Pd(C2H3O2)(2) and Pd(NO3)(2)) and evaluating their catalytic performance in the phenol hydrogenation to cyclohexanone. The Pd precursor or the carbon material has no obvious influence on the cyclohexanone selectivity, but strongly affects the catalytic activity. The Pd@C prepared via PdCl2 shows good performance among all tested catalysts due to higher Pd content and better Pd dispersion. Conversely, although Pd(NO3)(2) is easily adsorbed by carbon carriers, the catalytic activity is poor due to the worse Pd dispersion. The Pd(C2H3O2)(2) adsorption is very sensitive to the surface properties of carbon, and the N-doping can enhance the binding force between carbon and Pd2+, leading to higher Pd content and better Pd dispersion, thereby enhanced catalytic activity. This work would provide valuable references for the selection of Pd precursor for a given support. [GRAPHICS] .