ALD-coated ultrathin Al2O3 film on BiVO4 nanoparticles for efficient PEC water splitting

Bismuth vanadate（BiVO） is a promising semiconductor material for solar energy conversion via photoelectrochemical（PEC） water splitting,whereas its performance is limited by surface recombination due to trapping states.Herein,we developed a new method to passivate the trapping states on BiVOsurface using ultrathin aluminum oxide（AlO） overlayer by atomic layer deposition.The coated ultrathin AlOfilm on BiVOsignificantly enhanced photocurrent densities of the BiVOanodes under standard illumination of AM1.5 G（100 mW/cm2）.The electrochemical impedances and photoluminescence spectra were studied to confirm that the improved PEC water splitting performance of BiVOwas due to the decreased surface recombination state on BiVO,which effectively enhanced the charge separation.