Improved visible-light activities of g-C3N4 nanosheets by co-modifying nano-sized SnO2 and Ag for CO2 reduction and 2,4-dichlorophenol degradation

Graphitic carbon nitride (g-C3N4) usually exhibits weak photocatalytic activity for CO2 reduction and pollutant degradation. Herein, the visible-light activities of g-C3N4 nanosheets are successfully improved by co-modifying SnO2 and Ag, with ∼10-time and ∼8-time improvement respectively for CO2 conversion and 2,4-dichlorophenol (2,4-DCP) degradation as compared to the pure g-C3N4. Mainly based on the transient-state surface photovoltage responses, transient-state photoluminescence spectra and electrochemical analyses, it is confirmed that the improved photoactivities are attributed to the synergistic effect of the prolonged charge lifetime and the provided catalytic function by modifying SnO2 and Ag, respectively. In addition, the synergistic effect is also feasible by replacing Ag with Au. This work will provide an effective strategy for designing high-activity g-C3N4 based photocatalysts.