Thin-layer metal bismuth inserted into Bi2S3/C, N co-doped α-Fe2O3 achieving efficient photoelectrochemical water oxidation

Abstract

α-Fe2O3 has been considered a promising candidate for photoelectrochemical water splitting. Unluckily, the activity of α-Fe2O3 is significantly lower than the theoretical value due to the severe carrier recombination in the bulk phase and the slow kinetics of surface water oxidation. Herein, we developed a novel photoanode of Bi2S3/Bi/C, N co-doped α-Fe2O3. Compared with the reversible hydrogen electrode, this photoanode had a photocurrent density of 10.78 mA cm−2 at 1.23 V, which was about 3.44 times that of the pristine α-Fe2O3. Metallic Bi as an intermediate conducting layer effectively reduced the charge transport barrier between Bi2S3 and C, N co-doped α-Fe2O3. The Bi2S3 as a cover layer reduced the surface defect state of Bi2S3/Bi/C, N co-doped α-Fe2O3. The C, N co-doped α-Fe2O3 combined with Bi2S3/Bi forming a type-II heterojunction, which provided a sustained and powerful driving force for efficient carrier separation.