Directional transfer of photocarriers on CdS/g-C3N4 heterojunction modified with Pd as a cocatalyst for synergistically enhanced photocatalytic hydrogen production

Abstract

The photocatalytic hydrogen evolution, in which cocatalysts have a great importance, is considered an influential way for the generation of hydrogen. In this work, to develop the hydrogen evolution efficiency, as a facile and efficient photocatalyst is CdS nanoparticles were synthesized over the g-C3N4 sheets by hydrothermal method and then Pd metallic nanoparticles were doped onto the nanocomposite using the borohyride reduction method which is an effective and short-term deposition procesess for visible light-response hydrogen generation from water. Considering the experimental results, with the doping of Pd nanoparticles on the type II heterojuction structure formed as a result of the combination of CdS and g-C3N4, the recombination of the charge carriers is delayed, interfacial charge transfer is accelerated and more visible light absorption is achieved, resulting in increased production of photocatalytic hydrogen. The hydrogen evolution rate is 293.0 mu mol.h(-1).g(-1) over Pd-CdS/g-C3N4, which is 3.02, 3.15, 12.0 and 69.8 times as that of CdS/g-C3N4, Pd/CdS, CdS and g-C3N4, respectively. This study is expected to shed light on the development of more efficient and stable noble metal cocatalyst-supported type II semiconductor heterogeneous systems for effective photocatalytic hydrogen generation applications.