Construction of Asymmetric Phosphorus–Cobalt Dual Sites for Effectively Reducing CO₂ to CO

Abstract

With increasing global energy demand and growing concerns over climate change, methods for catalytic reduction of CO₂ have been extensively studied, among which graphitic carbon nitride (g-C₃N₄) attracts remarkable attention due to its easily available raw materials and outstanding chemical stability. However, its wide bandgap and low photon usage efficiency limit its application in photocatalysis. Doping g-C₃N₄ to introduce active sites can enhance its catalytic performance. Herein, asymmetric phosphorus–cobalt dual sites were introduced onto g-C₃N₄ via hydrothermal treatment and thermal polymerization. P (phosphorus) could enhance CO₂ adsorption, while Co (cobalt) functions as a metallic site to boost the separation rate of photogenerated carriers. A photocatalytic CO₂ reduction to CO with a rate of 93.2 μmol/(g·h) was achieved, which was two times that of g-C₃N₄. During stability testing, ethylene with a formation rate of approximately 2 μmol/(g·h) was observed, as well as trace quantities of methanol and acetic acid in the liquid products. This work shows a promising strategy by the introduction of asymmetric phosphorous–cobalt dual sites for efficient photocatalytic conversion of CO₂ to CO and C2 products.

Graphical Abstract

Keywords

g-C₃N₄ / Dual sites / CO₂ photoreduction / C₂H₄

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