Visible‐Light‐Responsive TiO2/NiFe Mixed Metal Oxide‐Carbon Photocatalytic Fuel Cell with Synchronous Hydrogen Peroxide Production

Abstract The photocatalytic fuel cell (PFC) synergistically utilizes the photocatalytic oxidation of biomass and the electrochemical reaction of the fuel cell to selectively reduce oxygen to produce hydrogen peroxide (H 2 O 2 ) at room temperature. Herein, we report a PEC system that NiFe‐layered double oxide (LDO)/TiO 2 as photoanode, carbon black as cathode for utilizing biomass and oxygen to simultaneously convert solar energy into electricity and produce hydrogen peroxide without applied electric bias. The photoanode catalyst was fabricated with TiO 2 ‐supported NiFe mixed metal oxides (MMO) which obtained by layered double hydroxides (LDHs) pyrolysis. The research results indicate that under solar irradiation, the photocurrent density and faraday efficiency have a significantly improved compared with pure NiO/TiO 2 . With methanol as the feeding fuel at the photoanode, the optimal device yields an excellent open circuit voltage (V oc ), short circuit current (J sc ) and a maximum power density (P max ) of 0.78 V, 1093 μA/cm 2 and 169 μW/cm 2 , respectively. This performance improvement is attributed to the Fe 3+ doped in NiFe‐MMO and use TiO 2 as an electron transport layer. Simultaneously, the hydrogen peroxide concentration reached 0.443 mM after 180 min illumination at the cathode, the generation rate was optimized to 0.126 μmol/min/cm 2 at neutral aqueous solution. The PEC system exhibited an excellent higher rate of production for H 2 O 2 , and faraday efficiency (FE) reached 31.7 %. This PFC is a green technology for photocatalytically oxidize biomass at the photoanode and convert solar energy into electricity as well as supply it to the cathode to reduce O 2 to produce H 2 O 2 efficiently.