Versatile Fabrication of Binary Composite SnO₂-Mn₂O₃ Thin Films by AACVD for Synergistic Photocatalytic Effect

In the present study, we prepared a SnO₂-Mn₂O₃ binary composite thin-film electrode by a single-step solution-based aerosol assisted chemical vapor deposition (AACVD) technique for photovoltaic applications. The grown composite thin films were characterized to determine their properties, such as structure, composition, morphology and band gap by field emission scanning electron microscopy (FESEM), x-ray diffractometry (XRD), Raman scattering, energy-dispersive x-ray spectrometry (EDX), x-ray photoelectron spectroscopy (XPS) and UV-Vis absorption spectrophotometry. The evaluation of photoelectrochemical (PEC) response of as-synthesized SnO₂-Mn₂O₃ composite photoelectrode, in comparison to the individual thin films of pristine SnO₂ and Mn₂O₃ prepared from their respective precursors under the same conditions, engendered a promising improvement in photocurrent density. The synergistic effect between SnO₂ and Mn₂O₃, the relevance of ball-like morphology, suitable and tunable energy band gap, and better absorbance under the visible range of light resulted in improved photocurrent of ~6.6 mA cm^-2 at +0.7 V versus Ag/AgCl electrode of the binary composite, which was 16.5- and 3.4-fold higher than that of the pure SnO₂ and Mn₂O₃, respectively. No apparent photocurrent decrease was observed during prolonged stability measurements for 300 s under one-sun illumination of 100 mW cm^-2. The results confirmed the enhancement in PEC activity due to reduced recombination rate of photoinduced electron-hole pairs and improved interfacial charge transfer between electrode/electrolyte interface, which boost the PEC performance of SnO₂-Mn₂O₃ binary composite thin film electrode towards water cleavage.