Solar‐Driven Faradaic Glycerol Upgrading in a Self‐Sustained Current‐Output Photoelectrochemical Device

Photoelectrochemical (PEC) oxidation of biomass‐derived glycerol offers a sustainable route to high‐value‐added chemicals. However, its efficiency is often limited by slow reaction kinetics and insufficient product selectivity. Here, we report the PEC glycerol oxidation to dihydroxyacetone (DHA) with a production rate of 366.1 mmol m −2 h −1 and selectivity of 64.1% over a photoanode of FeCo layered double hydroxide amorphous nanolayer on BiVO 4 substrate (BiVO 4 ‐FeCo LDH). The BiVO 4 ‐FeCo LDH with enriched oxygen vacancies could promote charge separation and transfer, yielding a photocurrent density twice that of bare BiVO 4 . In situ XPS analysis identifies Co sites as key redox centers, where the Co 2+ /Co 3+ transition mediates the oxidation process. It is deduced that the formation of adsorbed hydroxyl radicals is synergistically optimized by the heterojunction interface between BiVO 4 and FeCo LDH with oxygen vacancies, thereby effectively enabling selective glycerol oxidation for DHA. Moreover, a self‐sustained PEC device incorporating BiVO 4 ‐FeCo LDH photoanode simultaneously produces 237.7 μmol of DHA and delivers a stable power output of about 1 mW over 8 h. This work may underscore the potential of self‐sustained PEC system for biomass valorization coupled with electricity output.