Water‐Stable DMASnBr₃ Lead‐Free Perovskite for Effective Solar‐Driven Photocatalysis

Abstract

Water‐stable metal halide perovskites could foster tremendous progresses in several research fields where their superior optical properties can make differences. In this work we report clear evidence of water stability in a lead‐free metal halide perovskite, namely DMASnBr3, obtained by means of diffraction, optical and X‐ray photoelectron spectroscopy. Such unprecedented water‐stability has been applied to promote photocatalysis in aqueous medium, in particular by devising a novel composite material by coupling DMASnBr3 to g‐C3N4, taking advantage from the combination of their optimal photophysical properties. The prepared composites provide an impressive hydrogen evolution rate >1700 μmol g−1 h−1 generated by the synergistic activity of the two composite costituents. DFT calculations provide insight into this enhancement deriving it from the favorable alignment of interfacial energy levels of DMASnBr3 and g‐C3N4. The demonstration of an efficient photocatalytic activity for a composite based on lead‐free metal halide perovskite in water paves the way to a new class of light‐driven catalysts working in aqueous environments.

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

“…The chemometric study provided key information. First, it enabled pointing out the most convenient conditions for H 2 evolution, which resulted in a three-fold increase in HER relative to the first pilot work [13]; at the same time, the results collected clearly highlight the superior photocatalytic activity of DMASnBr 3 /g-C 3 N 4 .…”

“…Based on the preliminary findings obtained with carbon nitride-perovskite composites in TEOA solution [12,13], the two best performing materials, 33% DMASnBr 3 /g-C 3 N 4 and 5% PEA 2 SnBr 4 /g-C 3 N 4 , are investigated here for a systematic study of H 2 photoproduction from glucose aqueous solution. Glucose was selected as a biomass-derived sacrificial agent because in the wastewaters from food industry sugars are present at considerable amounts [4,5], and Pt was used as the reference metal co-catalyst because of its excellent properties for water reduction due to the large work function, resulting in a strong Schottky barrier effect [15,16].…”

“…Such an effect results from the positive band-alignment between the two semiconductors, namely the MHP and g-C 3 N 4 , and the perovskite is selected based on its bandgap in order to exploit this synergistic effect. It was also observed in an explorative test that such catalytic systems are capable of generating H 2 from glucose solution under UV-visible light, with HERs from 30 to 100 times higher relative to pristine g-C 3 N 4 [12,13].…”

“…Recently, coupling MHPs with g-C 3 N 4 has become a cutting-edge research field [2,10,11], although limited work has been done so far concerning photocatalysis [2]. Recently, lead-free MHPs showing an exceptional stability in water were synthesized and characterized [12][13][14], thus opening a new avenue for the preparation and application of innovative photocatalysts. In this context, our group advantageously coupled dimethylammonium and phenylethylammonium-based perovskites-DMASnBr 3 and PEA 2 SnBr 4 , respectively-to g-C 3 N 4 , providing new micro-sized composites with excellent photocatalytic properties towards H 2 production from triethanolamine (TEOA) aqueous solution; in particular, up to a 20-fold increase of hydrogen evolution rate (HER) was achieved compared to g-C 3 N 4 alone, due to a synergistic effect between the two constituents in the composite [12,13], essentially due to improved charge carrier separation.…”

“…Recently, lead-free MHPs showing an exceptional stability in water were synthesized and characterized [12][13][14], thus opening a new avenue for the preparation and application of innovative photocatalysts. In this context, our group advantageously coupled dimethylammonium and phenylethylammonium-based perovskites-DMASnBr 3 and PEA 2 SnBr 4 , respectively-to g-C 3 N 4 , providing new micro-sized composites with excellent photocatalytic properties towards H 2 production from triethanolamine (TEOA) aqueous solution; in particular, up to a 20-fold increase of hydrogen evolution rate (HER) was achieved compared to g-C 3 N 4 alone, due to a synergistic effect between the two constituents in the composite [12,13], essentially due to improved charge carrier separation. Such an effect results from the positive band-alignment between the two semiconductors, namely the MHP and g-C 3 N 4 , and the perovskite is selected based on its bandgap in order to exploit this synergistic effect.…”