Noble metal-free Ni(OH)2–g-C3N4 composite photocatalyst with enhanced visible-light photocatalytic H2-production activity

Abstract

Ni(OH)₂-modified graphitic carbon nitride (Ni(OH)₂–g-C₃N₄) composite photocatalysts were prepared by a simple precipitation method using g-C₃N₄ as support and nickel nitrate as precursor. The effect of Ni(OH)₂ content on the rate of visible-light photocatalytic H₂-production was studied for a series of Ni(OH)₂–g-C₃N₄ composite samples in triethanolamine aqueous solutions. The results demonstrated that Ni(OH)₂ was an efficient co-catalyst for the photocatalytic H₂ production of g-C₃N₄. The optimal Ni(OH)₂ loading was found to be 0.5 mol%, giving a H₂-production rate of 7.6 μmol h⁻¹ (with an apparent quantum efficiency (QE) of 1.1% at 420 nm), which approached that of optimal 1.0 wt% Pt/g-C₃N₄ (8.2 μmol h⁻¹). This work showed the possibility for the utilization of low cost Ni(OH)₂ as a substitute for noble metals (such as Pt) in the photocatalytic H₂ production for g-C₃N₄.