Respective electrode potential characteristics of photocatalytic fuel cell with visible-light responsive photoanode and air-breathing cathode

Photocatalytic fuel cell is a promising technology for simultaneous wastewater treatment and electricity generation. To more directionally improve the cell performance, a deep understanding of respective photoanode and cathode performances is of vital importance. In this work, therefore, a high-performance photocatalytic fuel cell with a visible-light responsive photoanode and an air-breathing cathode was developed to gain insight into each electrode potential characteristics. The potentials of each electrode were measured under different operational parameters. Experimental results showed that too low fuel concentration led to a serious mass transfer limitation at the photoanode and too high fuel concentration led to a low ionic conductivity, both of which deteriorated the cell performance. Therefore, there existed an optimum fuel concentration to achieve the best cell performance. It was also shown that an increase in the electrolyte concentration markedly improved both the photoanode and cathode performances due to enhanced reaction rates and lowered internal resistance, thereby leading to the increased cell performance. In addition, it was demonstrated that the light intensity significantly affected the photoanode potential and increasing the light intensity boosted the cell performance. The results obtained in this work provide the guidance for improving the photocatalytic fuel cell performance in future applications.