Acetaldehyde Production via Photocatalytic Heterolytic Dehydrogenation of Ethanol Accelerated by Tuning Lewis Acid-Base Pairs over CsGeX33 (X = Cl, Br, I) Halide Perovskites

초록

Photocatalytic hydrogen (H-2) production from ethanol offers the dual advantages of low energy consumption and the cogeneration of high-value chemicals. However, challenges remain in enhancing product selectivity and elucidating the precise reaction pathway. In this study, lead-free halide perovskites CsGeX3 (X = Cl, Br, I) were synthesized and utilized for the simultaneous generation of H-2 and acetaldehyde via photocatalytic ethanol oxidation under UV and visible light irradiation. Among them, CsGeI3 is reported for the first time as a highly effective photocatalyst, exhibiting the highest activity for both the hydrogen evolution reaction (HER) and the ethanol oxidation reaction (EOR). Under UV light irradiation for 3 h, CsGeI3 achieves H-2 and acetaldehyde yields of 97.74 and 92.08 mu mol g(- 1), respectively, with an apparent quantum yield (AQY) of 2.31% for H-2. Optical characterization and density functional theory (DFT) calculations revealed that the Lewis acid-base properties of CsGeI3 are mainly governed by the halogen component, enabling the selective activation and cleavage of the alpha-C-H and O-H bonds in ethanol, promoting heterolytic reactions that enhance the formation of both H-2 and acetaldehyde. This study provides new insights into the application of lead-free halide perovskites in tunable solar fuel generation and selective value-added chemical synthesis.

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