Enhancement in the photocatalytic activity of carbon nitride through hybridization with light-sensitive AgCl for carbon dioxide reduction to methane

Abstract

The production of carbon-neutral CH₄ solar fuel from CO₂ using a photocatalyst is an ideal future energy source to combat energy crisis and global warming concomitantly. In this contribution, effective photocatalytic reduction of CO₂ using a silver chloride (AgCl)/carbon nitride (CN) hybrid was demonstrated. The urea-derived CN was initially protonated to improve the subsequent dispersibility and anchorage of the AgCl particles. The nucleation process of AgCl was successively carried out by an in situ deposition–precipitation approach. The as-prepared AgCl/CN photocatalyst at an optimized loading exhibited a much higher visible-light photoactivity, giving an up to 2.5-fold enhancement in comparison to pure CN. This enhanced photocatalytic activity is attributed to enhanced light absorption provided by the surface plasmon resonance (SPR) of Ag⁰ which was simultaneously reduced during the photocatalytic reaction and the hierarchical heterojunction system which favourably inhibits electron–hole recombination.