Improved Proton Adsorption and Charge Separation on Cadmium Sulfides for Photocatalytic Hydrogen Production

Abstract

Cadmium sulfide has attracted wide attention in photocatalytic hydrogen production, due to its appropriate bandgap and band positions. However, high-rate photogenerated electron–hole recombination and few active sites on CdS lead to its low photocatalytic activity. Herein, a PANI/NCPP/CdS (PANI/NiCoP/NiCoPi/CdS) hybrid as a noble metal-free visible light-driven photocatalyst is reported, with metal phosphides, metal phosphates, and polyaniline (PANI) as reduction and oxidation cocatalysts, respectively. This hybrid not only facilitates the charge separation and transfer owing to the formation of heterojunction, but also improves the local concentration of H+ on the surface of catalysts due to the formation of the protonated amine groups on PANI, beneficial to hydrogen evolution reaction. As a result, the as-prepared photocatalyst could show a high hydrogen evolution rate of 170.3 mmol g−1 h−1 and an apparent quantum efficiency of 41.37% at 420 nm, representing one of the best performances of all-CdS-based photocatalysts.