Synergistic SnO₂-TiO₂ nanostructures: Dual function catalysts as efficient photocatalyst for industrial dye removal and bifunctional electrocatalyst for energy generation through overall water splitting

Abstract

To provide more sophisticated environmental applications, this work investigates the dual functioning of composite including titanium dioxide spheres anchored with tin dioxide nanospheres. Specifically, the fabricated composite was explored for the effective destruction of industrial dye pollutants (photocatalysts) and overall water-splitting capabilities (electrocatalysts). The removal of the anionic dye pollutant Methyl Orange (MO) was studied under both LED and sunlight irradiation, while the optimized composite was utilized for the degradation of the cationic dye Crystal Violet (CV) under sunlight exposure. A sample with 70 wt% SnO₂ nanospheres and 30 wt% TiO₂ spheres achieved 94 % degradation of anionic MO dye in 20 min under LED irradiation and 90 % degradation in 2 min under sunlight. For cationic Crystal Violet dye, it reached 92 % degradation within 20 min under sunlight irradiation. Electrochemical estimations exploiting linear sweep voltammetry (LSV) in an alkaline media of potassium hydroxide demonstrated that the composite catalysts that have optimum photocatalytic performance flashed heightened electrocatalytic performance compared to individual TiO₂, SnO₂, and other composite ratios. As an electrocatalyst, the 70 %Sn −30 %Ti loaded on the Ni-foam reveals an overpotential of 211 mV with a Tafel slope of 108.6 mV dec⁻¹ during HER activity. This electrode also exhibits superior performance during OER activity, with a minimal potential of 296.2 mV and a Tafel slope of 104.3 mV dec⁻¹. Furthermore, the electrolyzer composed of symmetric 70 %Sn-30 %Ti shows off a potential of 1.69 V. It maintains exceptional consistency with a negligible change of 1.17 % after 22 h, sustaining at a 10 mA cm⁻² current density during electrocatalytic overall water splitting. The focus is placed on showcasing the versatile potential of TiO₂@SnO₂ composites as highly effective photocatalysts and electrocatalysts.