Photochemical environment effect on V2O5-Fe2O3 heterostructures for efficient water splitting under visible light

To enhance eco-friendly energy generation from photoelectrochemical water splitting, the photoanode should be immersed in a photochemical environment for a long time. Here, V2O5 surfaces modified with Fe2O3 nanoparticles were synthesized using a simple method, and the stability of the synthesized photoanodes in a 0.1 M Na2SO3 electrolyte was investigated. The heterostructure was subjected to dark and light conditions, and their effect on the optical properties and kinetic behavior of the photoanode was analyzed. The V2O5-Fe2O3 heterostructures showed better light absorption than the pristine V2O5 and Fe2O3 structures. At 0 h immersion, the maximum photocurrent density was 0.25 mAcm(-2) for the V2O5-Fe2O3 photoanodes, which was 8-fold and 5-fold that of the V2O5 and Fe2O3 photoanodes, respectively, in the 0.1 M Na2SO3 electrolyte. Furthermore, the V2O5-Fe2O3 photoanode exhibited the lowest charge-transfer resistance (3.75 omega) and Tafel slope (68.1 mV center dot dec(-1)). After immersion for 96 h in the 0.1 M Na2SO3 electrolyte, the V2O5-Fe2O3 photoanode showed a significant decrease in photocurrent density, which could be owing to the shrinkage of active sites in the photoanode and increased charge-transfer resistance, exchange current density, limiting current density, and Tafel slope. Thus, the photochemical environment has a critical role in the photo-induced currents of the photoanode under illumination conditions.

Automated summary

In this study, V2O5-Fe2O3 heterostructures were synthesized and their stability and optical properties in a photochemical environment were investigated. The results showed that the V2O5-Fe2O3 heterostructures exhibited higher light absorption and photocurrent density, as well as lower charge-transfer resistance and Tafel slope. However, a significant decrease in photocurrent density was observed after prolonged immersion, which could be attributed to the shrinkage of active sites in the photoanode and increased charge-transfer resistance.