Angew: Enriched Surface Oxygen Vacancies of Photoanodes via Photoetching with Enhanced Charge Separation！
Posted on 2019年11月27日 14:56
Foreign element doping could improve the charge transport of photoelectrodes, however, new recombination centers may be introduced. This paper describes a facile photoetching approach that alleviates the negative effects from bulk defects by confining the oxygen vacancy (O vac) at the surface of BiVO4 photoanode, via a 10‐minute photoetching. This strategy could induce enriched O vac at the surface of BiVO4, which avoids the formation of excessive bulk defects. A mechanism is proposed to explain the enhanced charge separation at the BiVO4/electrolyte interface, which is supported by density functional theory (DFT) calculations. The optimized BiVO4 with enriched surface Ovac presents the highest photocurrent among undoped BiVO4 photoanodes. Upon loading FeOOH/NiOOH cocatalysts, photoetched BiVO4 photoanode reaches a considerable water oxidation photocurrent of 3.0 mA cm‐2 at 0.6 V vs. reversible hydrogen electrode. An unbiased solar‐to‐hydrogen conversion efficiency of 3.5% is realized by this BiVO4 photoanode and a Si photocathode under 1 sun illumination.