Promotional Effect of Bimetallic PtSn/C Catalysts for the Selective Synthesis of Glucaric Acid via Glucose Oxidation

ABSTRACT

Glucose valorization offers a sustainable route for the production of high‐value chemicals from renewable biomass resources. In this study, the selective aerobic oxidation of glucose to glucaric acid was investigated over activated carbon‐supported Pt–Sn catalysts. Among the catalysts examined, 5Pt1.5Sn/C exhibited the highest glucaric acid yield of up to 68% under optimized conditions. The reaction proceeds via consecutive oxidation steps: (i) glucose to gluconic acid, (ii) gluconic acid to glucuronic acid, and (iii) glucuronic acid to glucaric acid, with the second step identified as the rate‐determining step. Product selectivity is strongly influenced by reaction conditions, particularly temperature and pH, where mild conditions favor selective formation of glucaric acid while suppressing C─C bond cleavage to low‐carbon by‐products. Physicochemical characterization reveals that Sn incorporation induces both electronic and geometric modification of Pt and provides additional adsorption sites, resulting in optimized intermediate adsorption and enhanced oxygen activation. Furthermore, extension of the substrate scope to other aldoses confirms the generality of the bimetallic effect, demonstrating that PtSn/C catalysts are effective for the selective synthesis of aldaric acids. These findings highlight that precise control of Pt–Sn interactions and reaction conditions are critical for achieving high selectivity toward C6 dicarboxylic acid.