A ternary calabash model photocatalyst (Pd/MoP)/CdS for enhancing H2 evolution under visible light irradiation

Abstract

Noble metal and non-noble metal co-catalysts have their own advantages for improving photocatalytic hydrogen evolution. Here, we report a new composite co-catalyst (Pd/MoP) and a ternary photocatalyst (Pd/MoP)/CdS for hydrogen evolution. The optimum photocatalytic hydrogen evolution of (Pd/MoP)/CdS reaches 943 μmol/h, which is 2.1 times of MoP/CdS and 4.4 times of Pd/CdS. Transient photocurrent responses, photoluminescence spectroscopies, and surface photovoltage spectroscopies demonstrated the combination of (Pd/MoP) makes high-efficiency of charge separation on CdS. Galvanostatic charge/discharge and cyclic voltammetry tests revealed MoP mainly serves as a reservoir to store photo-excited electrons from CdS. Electrochemical impedance spectra and linear sweep voltammetry measures revealed Pd mainly acts as active sites for hydrogen evolution. Most importantly, the functions of each part of ternary photocatalyst for hydrogen evolution have been clarified, and a ternary calabash model photocatalyst for hydrogen evolution is put forward.