MOF-Derived Cu/CeO₂ Nanocatalysts Using Ascorbic Acid for CO Oxidation

Tunable electronic properties of supported Cu/CeO 2 catalysts are critical for improving the active site activity in catalysis. In this contribution, we propose a surface engineering protocol that utilizes unique ascorbic acid (AA) properties to generate surface defects and modify the electronic properties of Cu–Ce catalysts. This approach relies on forming abundant (Ce 3+ -Ov) defective sites on the CeO 2 surface synthesized with a Ce-benzene-tricarboxylate metal–organic framework (MOF) as a precursor through AA adsorption. Subsequently, Cu sites can be effectively anchored onto the generated Ce 3+ -Ov, exhibiting excellent electronic transfer between (Ce 3+ -Ov/Ce 4+ ↔ Cu 2+ /Cu + ) CuCe, resulting in highly active Cu + with well-balanced Ce 3+ -Ov defects. A high fraction of Cu + with Ce 3+ -Ov was dedicated to the presence of AA. The resultant Cu/AA-MOF-CeO 2 catalyst demonstrated outstanding performance toward CO oxidation (90–95 °C), being far superior to that of the conventionally prepared Cu/MOF-CeO 2 catalyst (110–115 °C). In-depth characterizations confirmed that the remarkable performance was considerably related to the enhanced Cu–Ce interaction, enriched Cu + active sites, and balanced Ce 3+ -Ov defects. This work highlights the potential of the Cu/AA-MOF-CeO 2 catalyst as a sustainable solution for low-temperature catalytic CO oxidation reaction.