In this work, a solar responsive photocathode with the CuS/Cu2O/Cu cubic nanoparticles was developed to facilitate the separation of the electron/hole pairs so as to enhance the photoelectrochemical activity. The EIS and LSV results indicated the developed CuS/Cu2O/Cu photocathode showed better photoelectrochemical activity toward the oxygen reduction reaction than the Cu2O/Cu photocathode. Good stability of the developed CuS/Cu2O/Cu photocathode was confirmed by the photocurrent vs time measurement. Besides, the developed CuS/Cu2O/Cu photocathode was also assessed by incorporating it into a photocatalytic fuel cell with the lateral design for simultaneous wastewater treatment and electricity generation. It was shown that higher cell performance was achieved than the Cu2O/Cu photocathode. The performance of the photocatalytic fuel cell with the developed photocathode was then studied under various operating conditions. Experimental results indicated that increasing the light intensity and the Na2SO4 electrolyte concentration and decreasing the liquid flow rate in the testing range could improve the cell performance. This study provides a new photocathode design for the photocatalytic fuel cell applications and other photoelectrochemical systems. (C) 2019 Elsevier Inc. All rights reserved.