Suppressing catalyst deactivation on Pd/CeO2 for selective oxidation of glucose into gluconic acid

Abstract

Catalytic oxidizing of glucose into gluconic acid (GLUC) provides an attractive and feasible pathway for the high value-added utilization of glucose, in which Pd-based catalysts deliver outstanding catalytic performance. However, the surface poisoning of Pd caused by the strong adsorption of GLUC becomes the bottleneck for their further applications. Herein, oxygen-vacancy-riched ceria supported Pd catalyst (Pd/CeO2) is employed, which effectively alleviates the catalyst deactivation, and realizes high catalytic activity and stability with 100 % GLUC selectivity for glucose oxidation at room temperature. Kinetic analysis confirms the strong anti-poisoning ability of Pd/CeO2. The superior catalytic performance is attributed to the modulation of the electronic structure of Pd nanoparticles by the strong metal-support interaction between Pd and CeO2. The valence band photoemission spectra reveal that the downshift of the d-band center of Pd leads to the weak adsorption of GLUC on Pd/CeO2. Meanwhile, kinetic isotope effect experiments indicate that the OHads generated from H2O dissociation on the CeO2 surface affords another path for glucose oxidation, thus improves the catalytic activity.