Cu/Cu₂O nanoparticles supported on electrospun carbon nanofibers as high-performance cathodic catalyst for photocatalytic fuel cell

Designing efficient and stable photocathodes remains a critical challenge for advancing high-performance photocatalytic fuel cell (PFC) systems toward simultaneous pollutant removal and energy conversion. Herein, we report a novel Cu-Cu₂O/carbon nanofibers (CNFs) photocathode, synthesized via an electrospinning-calcination method, in which the Cu-Cu₂O heterostructures are uniformly anchored onto conductive CNFs rich in oxygen vacancies. As a proof of concept, a dual-photoelectrode PFC system was constructed to evaluate the performance of the Cu-Cu₂O/CNFs photocathode. The PFC achieved an 83 % degradation rate for Rhodamine B (RhB) in 2 h and a maximum power density (P_max) of 42.99 μW/cm², markedly outperforming the commercial Cu₂O-based cathode PFC system. Moreover, the PFC system assembled with the Cu-Cu₂O/CNFs photocathode exhibited consistent degradation efficiency and power output over multiple cycles, demonstrating that the cathode plays a crucial role in ensuring the long-term stability of the system. Experimental and theoretical calculation results confirm that the unique local electronic structure and coordination environment at the Cu/Cu₂O interface promote O₂ adsorption and lower the energy barrier for the oxygen reduction reaction (ORR). This work demonstrates a rational strategy for designing high-efficiency Cu-based photocathodes and offers new insights into optimizing photoelectrocatalytic materials for environmental and energy applications.