Enhanced photocatalytic H₂ production on CdS nanorod using cobalt-phosphate as oxidation cocatalyst

Highlights: • Co-Pi/CdS composites were synthesized by a simple photodeposition method. • The composites showed superior photocatalytic H₂ production activity. • The optimal H₂ production rate of Co-Pi/CdS was even higher than that of Pt-CdS. • Co-Pi is a good oxidation cocatalyst used for capture of photogenerated hole. - Abstract: Employing visible light responsive semiconductor for photocatalytic hydrogen production by water splitting is an efficient way for utilizing renewable solar energy to solve the depletion of fossil fuel and environmental contamination. Herein, we report enhanced photocatalytic H₂-production performance over CdS nanorod using cobalt-phosphate (Co-Pi) as a water oxdation cocatalyst. The optimal Co-Pi modified CdS nanocomposite photocatalyst with the Co-Pi content of 8.4 mol% has a superior visible light H₂-production rate of 13.3 mmol h⁻¹ g⁻¹ with an apparent quantum efficiency of 24.3% at 420 nm, which is even higher than that of 1 wt% Pt-CdS (11.3 mmol h⁻¹ g⁻¹) under the same conditions. The enhanced visible-light photocatalytic H₂ production activity was attributed to the hole trapping and collecting ability of Co-Pi cocatalyst, which could effectively suppress the recombination of photogenerated electron-hole pairs and increase the electron density for hydrogen production. This work shows a possibility of using earth-abundant Co-Pi as cocatalyst for enhancing photocatalytic H₂ production.