Photocatalytic carbon dioxide reduction to fuels Over Cu- Loaded g-C₃N₄ nanocatalyst under visible light

Photocatalytic carbon dioxide (CO₂) conversion to chemicals and fuels has gained significant consideration in industrial and scientific research. In this study, photocatalytic CO₂ reduction to fuels over Cu-loaded graphitic carbon nitride (g-C₃N₄) under visible light irradiation has been investigated. The photocatalysts, synthesized by pyrolysis and impregnation method, were characterized by X-ray diffraction (XRD) Fourier transform infrared (FTIR) and Scanning electron microscopy (SEM). Interestingly, CO₂ was efficiently converted to CH₄ and CH₃OH with smaller amounts of C₂H₄ and C₂H₆ hydrocarbons. The yield of CH4 evolution as the main product over 3 wt. % Cu/g-C₃N₄was 217.8 μmole/g.cat under visible light irradiation, significantly higher than the amount of CH₄ produced over the pure g-C₃N₄ catalyst (119 μmole/g.cat). The enhancement was attributed to charge transfer property and suppressed recombination rate by Cu-metal. The Cu-metal loaded into g-C₃N₄ enhanced CO₃ reduction efficiency for CH₄ production while the pure g-C₃N₄ was promising for both CH₄and CH3OH production. The single step conversion of CO₂ to CH₄ and CH₃OH with appreciable amount of hydrocarbons under solar energy registered good photo-Activity and selectivity of Cu/g-C₃N₄ catalyst. A photocatalytic reaction mechanism was proposed to corroborate with the experimental results over the Cu-loaded g-C₃N₄ photocatalyst.