Carbon Nitride-Perovskite Composites: Evaluation and Optimization of Photocatalytic Hydrogen Evolution in Saccharides Aqueous Solution

The application of hybrid photocatalysts made of carbon nitride and lead-free perovskites, namely DMASnBr(3)/g-C3N4 and PEA(2)SnBr(4)/g-C3N4, for the H-2 evolution from saccharides aqueous solution is described. The novel composites were tested and compared in terms of hydrogen evolution rate (HER) under simulated solar light, using Pt as a reference co-catalyst, and glucose as a representative sacrificial biomass. The conditions were optimized to maximize H-2 generation by a design of experiments involving catalyst amount, glucose concentration and Pt loading. For both materials, such parameters affected significantly H-2 photogeneration, with the best performance observed using 0.5 g L-1 catalyst, 0.2 M glucose and 0.5 wt% Pt. Under optimized conditions, DMASnBr(3)/g-C3N4 showed a 5-fold higher HER compared to PEA(2)SnBr(4)/g-C3N4, i.e., 925 mu moles g(-1) h(-1) and 190 mu moles g(-1) h(-1), respectively (RSD <= 11%, n = 4). The former composite, which affords an HER 15-fold higher in aqueous glucose than in neat water, provided H-2 also with no metal co-catalyst (around 140 mu moles g(-1) h(-1)), and it was reusable for at least three photoreactions. Encouraging results were also collected by explorative tests on raw starch solution (around 150 mu moles g(-1) h(-1)).