A Three-Dimensional Bi 2 S 3 @Sn: α-Fe 2 O 3 Heterojunction with Improved Charge Separation for Photoelectrochemical Water Oxidation

The rational design and construction of heterojunctions as the photoanodes are considered as the effective strategy to enhanced photoelectrochemical (PEC) water splitting performance. Herein, Bi2S3@Sn: α-Fe2O3 nanowires heterostructures were successfully constructed by the two-step hydrothermal method. The rational design of Bi2S3@Sn: α-Fe2O3 yielded photocurrent density up to 4.18 mA/cm2(1.23 VRHE), which was 5.5 times higher than the pristine α-Fe2O3. The superior PEC performance can be attributed to the efficient charge separation efficiency by the type II heterojunction, which was evidenced by the photoluminescence spectroscopy. The impedance spectra revealed the two semiconductors coexisted in the heterojunction, and it also showed the charge transfer resistance decreased significantly, which can be attributed to the enhanced charge separation efficiency within the heterojunction. This work is expected to provide the rational strategy to design and prepare efficient heterostructures to modulate the charge separation efficiency.