L‐Ascorbic Acid‐Modified NH 2 ‐MIL‐125 for Efficient Photocatalytic Bioethanol‐to‐Ethylene Conversion

ABSTRACT Photocatalytic ethanol dehydration offers a sustainable route for ethylene production. In this study, AA@Cu‐NH 2 ‐MIL‐125 composites were successfully constructed by loading copper species onto NH 2 ‐MIL‐125, followed by in situ reduction with L‐ascorbic acid to obtain more Cu + sites. Under simulated solar irradiation, the optimized catalyst AA@Cu‐NH 2 ‐MIL‐125 exhibited remarkable activity for ethanol dehydration, achieving a C 2 H 4 production rate of 574 µmol·g −1 with 98.3% selectivity toward C 2 H 4 products in 4 h. Additionally, the catalyst demonstrated excellent stability, maintaining approximately 91% of its initial activity over six consecutive cycles. Mechanistic investigations revealed that the modification of L‐ascorbic acid effectively induced the strong Brønsted acid sites and enhanced the separation of the photogenerated charges. In situ Raman spectroscopy was employed to monitor the photocatalytic process in real‐time, indicating that the L‐ascorbic acid modification promotes ethoxy deprotonation through Brønsted acid sites, thereby significantly enhancing C 2 H 4 selectivity. This work establishes a rational material design strategy and mechanistic foundation for Cu + ‐based photocatalysts, paving the way for efficient, solar‐driven ethylene production from renewable bioethanol.