Rational design of TiO2/BiSbS3 heterojunction for efficient solar water splitting

Solar induced water splitting with semiconductor photoelectrodes has been recognized as a sustainable alternative for addressing the energy crisis and pollution by creating hydrogen as a clean fuel. Insufficient light absorption and quick recombination of excitons are the most major bottlenecks in the emergence of semiconductor-based photocatalysts. The major challenge to the commercialization of this technique is the development of photoelectrodes that fulfill the PEC water-splitting requirements. In this study, As a photoanode for PEC water splitting, BiSbS3 NRs were grown on TiO2 films using a simple chemical bath deposition method. Such heterojunctions were chosen to amplify and expand the absorption of visible light, charge transport, charge separation and electrical conduction. The results show that the TiO2/BiSbS3 heterojunction photoanode exhibits relatively low charge transfer resistance, a highest current density of 5.0 mA.cm−2 and STH conversion efficiency of 4.5% at 0.3 V vs RHE. The system's long-term stability was also evaluated for a period of 10,000 s and hydrogen evolution was carried out for 9000 s. Photoluminescence (PL) spectroscopy confirms that TiO2/BiSbS3 heterojunction exhibits stronger light absorption and efficient charge transfer compare to bare TiO2 and BiSbS3. Composite exhibits larger Brunauer − Emmett − Teller (BET) surface area compare to bare TiO2 and BiSbS3 which have contributed in excellent PEC performance compare to bare materials.