S-Scheme TiO2/CuNb2O6 Nanocomposite Photocatalyst with Enhanced H2 Evolution Activity from Aqueous Glycerol Solution

Steeringof photoexcitons via interface engineering of semiconductorphotocatalysts is key to achieving a stable and efficient photocatalystfor continuous hydrogen production. Among them, the development of1D nanostructures with several advantageous properties such as widesurface area, effective light harvesting, and increased electron movingkinetics has received special attention. In this work, 1D titaniananobars were successfully synthesized via the methanol-assisted solvothermalmethod, in which alcohol formed hydrogen bonds with nuclei, whichconsequently encouraged the growth of nanobars. Following this, thetitania nanobars were integrated with solvothermally synthesized monoclinicCuNb(2)O(6) nanoparticles. TEM analysis revealedthe formation of TiO2 nanobars and their uniform interactionwith CuNb2O6 nanoparticles. A S-scheme heterojunctionis formed at the interface of TiO2 nanobars and CuNb2O6 nanoparticles. 1D morphology of titania andCuNb(2)O(6) plays a key role in light absorptionand boosts the photocatalytic activity by promoting the separationand transfer of photoexcited charge carriers. The electrons at theTiO(2) conduction band and holes at the valance band of CuNb2O6 facilitated recombination at the heterojunction.The remaining electrons at the conduction band of CuNb2O6 and holes at the valance band of TiO2 tendto participate in redox reactions at their terminals. As the loadingof CuNb2O6 increases, the rate of activity initiallyincreases and then decreases, which is consistent with the trend forlight penetration-dependent photocatalytic hydrogen evolution. Theband edge potentials of TiO2 and CuNb2O6 were also revealed using VB-XPS and UPS analysis. In additionto catalytic stability, the effect of glycerol concentration, catalystloading, time on stream, recyclability, and parametric analysis whichaided in the discovery of ideal experimental conditions is revealed.Under optimal conditions, the photocatalyst showed an enhanced rateof H-2 generation (146 mmol h(-1) g(cat) (-1)) under simulated solar light irradiation.The solar to H-2 conversion efficacy is also discussed withcomparison.