Nanospheres and nanorods structured Fe2O3 and Fe2−xGaxO3 photocatalysts for visible-light mediated (λ ≥ 420 nm) H2S decomposition and H2 generation

This article reports our investigation on H2 generation from visible light (λ ≥ 420 nm) photodecomposition of H2S by nanomaterial catalysts, α-Fe2O3 and its chemically modified Fe2−xGaxO3 (Ga substitution at x = 0.6, FeGaO3-I and x = 1.0, FeGaO3-II). Simple template-free hydrothermal technique was employed to synthesize the three photocatalysts. XRD study reveals rhombohedral nanocrystalline structure and FESEM shows nanospheres morphology for Fe2O3 and nanosticks/nanorods for both FeGaO3-I, and FeGaO3-II. In H2 generation, Fe2O3 and FeGaO3-II perform moderate and almost same activities in the fresh and used conditions (quantum yield, QY = 6.0–6.8% at 550 nm). Contrarily, fresh FeGaO3-I exhibits a greater activity (11.2% QY) and the activity is further enhanced (QY = 15.3%) on regeneration and reuse. The intricacy, as resolved by XRD and FESEM, appears to take place through morphology transformation. The present work, thus, successfully demonstrates H2 generation from H2S by nanostructured photocatalysts involving morphology dependent activity enhancement.