Bias‐Free Photoelectrochemical Glycerol Oxidation to Formic Acid Enhanced by Ho‐F Interface on BiVO4

Abstract Photoelectrochemical glycerol oxidation to high‐value‐added formic acid (FA) products is one of the promising strategies to replace the low‐value oxygen evolution reaction. However, the process is hindered by the slow kinetics of PEC C─C bond cleavage of polyols. Herein, a holmium and fluorine modified bismuth vanadate (HoF/BVO) semiconductor was constructed to obtain a highly selective FA product through PEC glycerol oxidation reaction. The resultant HoF/BVO photoanode exhibited an excellent performance with a high FA selectivity of 85.1% and a FA Faradaic efficiency of 73% at 1.23 V RHE , maintaining a stable durability for 25 h. More importantly, a self‐driven PEC integrated system was constructed in which HoF/BVO as a photoanode efficiently catalyzed FA synthesis, and Co/DACN as a cathode simultaneously facilitated oxygen reduction reaction. The unassisted PEC device achieved a photocurrent density of ∼2.3 mA cm −2 and a FA yield of 213.4 µmol cm −2 with 16 h. In situ characterization and density functional theory calculations demonstrated and supported the surface modification induced electronic structure reconstruction along the C─C bond activation pathway, promoting the highly selectivity of FA product. This work offers a new approach for the conversion of biomass‐derived compounds to valuable chemicals using a self‐biased, solar‐driven photoelectrochemical cell.