Photocatalytic fuel cell (PFC)Ag@Fe2O3 cathodePhotocatalytic degradationReduction of Cr(VI)Photoelectrical conversionWASTE-WATER TREATMENTNANOTUBE ARRAY PHOTOANODEEFFICIENT REMOVALOXYGEN REDUCTIONHIGHLY EFFICIENTFACILE SYNTHESISELECTRO-FENTONNANOCOMPOSITENANOPARTICLESPERFORMANCE