Efficient Aerobic Oxidation of Glucose to Gluconic Acid over Activated Carbon‐Supported Gold Clusters

The catalytic performance of the atomically precise gold cluster‐Au38(PET)24 (PET=2‐phenylethanethiolate), immobilized on activated carbon (AC), was investigated for the aerobic oxidation of glucose to gluconic acid. The Au38(PET)24/AC‐120 catalysts, annealed at 120 °C in air, exhibited high catalytic activity and significantly better performance than the corresponding catalysts Au38/AC‐150 and Au38/AC‐300 (treated at 150 and 300 °C to remove the protecting thiolate ligands). The high activity of the robust Au cluster was a result of the partial ligand removal, providing catalytically active sites, which were evidenced by TEM, X‐ray photoelectron spectroscopy, thermogravimetric analysis, and Fourier‐transform IR spectroscopy. Au38(PET)24/AC‐120 also showed excellent recyclability (up to seven cycles). The turnover frequency for the Au38(PET)24/AC‐120 catalyst was 5440 h−1, which is higher than for the Pd/AC, Pd‐Bi/AC, and Au/AC under identical reaction conditions. This new ultra‐small gold nanomaterial is expected to find wide application in other catalytic oxidations.