The Synergetic Benefits of Passivation Layer and Catalytic Layer on Hematite for Efficient Water Splitting

Abstract

In photoelectrochemical (PEC) water splitting systems, an overlayer on the surface of the semiconductor has always been pursued with tremendous interest. The multicomponent Fe2O3/FexSn1−xO4/FeOOH photoanode is designed to achieve efficient water splitting. The photocurrent density of Fe2O3/FexSn1−xO4/FeOOH photoanode is 1.70 mA cm−2 at 1.23 V vs reversible hydrogen electrode (RHE), improved by 121.1%, compared with that of the pristine hematite photoanode (0.77 mA cm−2 at 1.23 V vs RHE) under air mass (AM) 1.5 illumination (100 mW cm−2). Detailed characterization is carried out to explore the main factors of photocurrent enhancement. The excellent PEC performance could be attributed to the synergetic benefits of FexSn1−xO4 passivation layer and FeOOH catalyst, which reduce the rate of electron–hole recombination and improve water oxidation reaction kinetics. The results prove a new sight to achieve efficient PEC water splitting.