Enhanced photocatalytic hydrogen production under UV light: improved electron transfer in mesoporous Co–SnO2 for energy exploration and blue LED applications
摘要
This work aims to synthesize and evaluate SnO2 and co-implanted SnO2 nanoparticles for photocatalytic hydrogen evolution and electrochemical applications. SnO2 nanoparticles were produced hydrothermally, and co-implanted SnO2 was prepared using photo-induced chemical processes, resulting in ordered cobalt incorporation. To determine their versatility, they were characterized structurally, magnetically, and optically. Cobalt-induced surface defects and exchange interactions increased the ferromagnetic saturation (MS) in Co–implanted SnO2, as indicated by vibrational sampling magnetism (VSM) analysis. Pigment analysis using the CIE 1976 system revealed a blue shift in emission, with pigment coordinates moving from (x = 0.26, y ≈ 0.36) to (x ≈ 0.22, y ≈ 0.30) for the Co-implanted SnO2. This indicates better quantum confinement and potential optoelectronic applications. Photocatalytic hydrogen evolution studies revealed a high production rate of 80 μmol/h under UV–visible irradiation. The increased activity was attributed to the mesoporous structure and cobalt doping, which increases the surface area and reduces electron–hole recombination. Mott-Schottky analysis revealed a favourable shift in the flat-band energy (Efb). This indicates a high charge separation efficiency and a negative conduction band edge, which are favourable for hydrogen evolution. A high specific capacitance of 685 F/g at a current density of 1 A/g and an excellent retention of 92% over 800 charge–discharge cycles were demonstrated by electrochemical measurements of the assembled SnO2. Electrochemical impedance spectroscopy (EIS) Nyquist plots showed a low charge transfer resistance of about (Rct) 3.2 Ω, indicating excellent electron mobility. The enhanced charge transfers and low recombination rates were further verified by transient photovoltage responses. These results highlight the potential of Co-implanted SnO2 nanocomposites as high-performance materials for energy storage and hydrogen evolution. This research provides essential design ideas for power band modulation, defect engineering, multifunctional catalysts, and optimised nanostructures for improved performance in sustainable energy applications. Their performance in photocatalytic processes is aided by assessing their BET surface area and electrochemically active surface area (ECSA).
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