Ag nanofilm enhanced S-type Ag@AgCl/tubular g-C3N4/Ti photoanode visible light response photocatalytic fuel cell

In this study, based on Ag@AgCl/tubular g-C3N4 (Ag@AgCl/TCN) composite, Ag nanoparticles were deposited on its surface to form Ag nanofilm enhanced composite through photoreduction of excessive silver nitrate solution to obtain Ag nanofilm Ag@AgCl/TCN photocatalyst. Finally, Ag nanofilm Ag@AgCl/TCN/Ti photoanode was successfully prepared by silica-sol drop-coating method, and assembled with Cu2O/Cu cathode to construct a photocatalytic fuel cell (PFC). Ag nanofilm can not only enhance the light absorption and utilization of Ag@AgCl/TCN/Ti, but also extend its light response wavelength to visible light, and be used as an electron transfer medium to reduce internal resistance. The photocurrent density and the photoconversion efficiency of the Ag nanofilm/Ag@AgCl/TCN/Ti are 8.01mA·cm-2 and 1.24%, respectively, which are 2.49 and 2.54 times those of the Ag@AgCl/TCN/Ti photoanode, respectively. The first-order kinetic constant and the maximum power density of the Ag nanofilm-coated Ag@AgCl/TCN/Ti-Cu2O/Cu PFC system are 0.064min-1 and 46.37 μW·cm-2, respectively, which are 1.39 and 1.94 times those of the Ag@AgCl/TCN-Cu2O/Cu PFC system, respectively. In addition, it degraded more than 95% of rhodamine B, 72.68% of tetracycline and 54.25% of bisphenol A within 60min. The excellent performance of Ag nanofilm/Ag@AgCl/TCN/Ti-Cu2O/Cu is due to the strengthening of Ag nanofilm and the formation of S-type heterojunctions between AgCl and TCN. Free radicals (•Cl, h+, •OH, •O2-) and non-radicals (1O2) are involved in the degradation reaction of RhB degradation. It is worth noting that 6% Ag nanofilm/Ag@AgCl/TCN/Ti-Cu2O/Cu has a positive effect on the production of •O2-, and its output is approximately 1.89 times that of the Ag@AgCl/TCN/Ti-Cu2O/Cu. A series of material characterization experiments have been completed and possible mechanisms of operation have been proposed. This study provides a new scheme for the design and preparation of high-efficiency photoanode of PFC.