Effects of external parameters and mass-transfer on the glucose oxidation process catalyzed by Pd–Bi/Al2O3

Abstract

The catalytic properties of a bimetallic 3.5% Pd–2.4% Bi catalyst supported on Al₂O₃ were studied in a glucose oxidation reaction in sodium gluconate at various pHs, temperatures and [Glu] : [Pd] ratios. It was found that pH 9 and temperature 60 °C are the best conditions for the Pd₃Bi/Al₂O₃ catalytic system. These reaction parameters contribute to obtaining sodium gluconate with 56.6% yield while maintaining a selectivity of 99.9%. The calculated activation energy was 67.7 kJ mol⁻¹. The oxygen transfer rate investigation allowed us to conclude that the reaction proceeds in a kinetic mode. The catalyst showed activity and stability in three catalytic cycles (X_Glu = 56.6–62.8, S_SGlu > 99.9%). The decrease in catalytic activity in the fourth and fifth catalytic cycles is associated with a change in the valence-phase state of the catalyst surface established using XPS.