Exploring the Impact of Bi Content in Nanostructured Pd-Bi Catalysts Used for Selective Oxidation of Glucose: Synthesis, Characterization and Catalytic Properties

Abstract

This work is devoted to the study of the effect of small Bi additives on the functional properties of Pdx:Bi/Al2O3 catalysts in the selective oxidation of glucose to gluconic acid. The catalysts obtained by the joint impregnation method were characterized (TEM) by high dispersion of bimetallic nanoparticles with a median diameter of 4–5 nm. The structure of the Pd-Bi solid solution was confirmed via XPS and showed a change in the valence state of Pd and Bi depending on the Bi content, as well as the fraction of the oxidized state of Bi. TPR-H2 revealed various forms of Pd, including PdO and mixed Pd-O-Bi structures. The Pd10:Bi1/Al2O3 catalyst demonstrated the highest efficiency (77.2% glucose conversion, 96% sodium gluconate selectivity), which is due to the optimal ratio between Pd and Bi, ensuring the stabilization of metallic Pd and preventing its oxidation.