Oxidative Polyoxometalates Modified Graphitic Carbon Nitride for Visible-Light CO Reduction.

Developing a photocatalysis system for converting CO to valuable fuels or chemicals is a promising strategy to address global warming and fossil fuel consumption. Exploring photocatalysts with high-performance and low-cost has been two ultimate goals toward photoreduction of CO. Herein, noble-metal-free polyoxometalates (Co4) with oxidative ability was first introduced into g-CN resulted in inexpensive hybrid materials (Co4@g-CN) with staggered band alignment. The staggered composited materials show a higher activity of CO reduction than bare g-CN. An optimized Co4@g-CN hybrid sample exhibited a high yield (107 μmol g h) under visible-light irradiation (λ ≥ 420 nm), meanwhile maintaining high selectivity for CO production (94%). After 10 h of irradiation, the production of CO reached 896 μmol g. Mechanistic studies revealed the introduction of Co4 not only facilitate the charge transfer of g-CN but greatly increased the surface catalytic oxidative ability. This work creatively combined g-CN with oxidative polyoxometalates which provide novel insights into the design of low-cost photocatalytic materials for CO reduction.