Optimization of a thin film photocatalyst for hydrogen production: Effect of In-doping in ZnO photo-corrosion suppression

Abstract

To avoid ZnO photocorrosion, In-doped ZnO nanorods were grown using chemical bath deposition by varying the In concentration (0.5, 0.75, and 1 mol %). The increase in the In load enhanced the photocatalytic activity for hydrogen production, evolving 10 times more hydrogen in the ZnONRD/1-In (1 % In) sample compared to bare ZnO NRD, associated with larger presence of dislocations in this sample, which acted as electron traps. Unfortunately, the recyclability cycles indicated that this sample was not stable because its photoactivity decreased by 90 %. Despite this, it was observed that the ZnONRD/0.5-In film (0.5 % In) maintained constant its gas evolution, indicating good stability and possibly a photocorrosion suppression. This feature was confirmed with a long reaction time, reaching maximum hydrogen evolution at 48 h (up to 50 µmol). Similarly, hydrogen production was increased by a factor of 43 by adding Na₂S/Na₂SO₃ as a sacrificial agent, confirming sample efficiency.