Strong Electronic Interaction between Amorphous MnO2 Nanosheets and Ultrafine Pd Nanoparticles toward Enhanced Oxygen Reduction and Ethylene Glycol Oxidation Reactions

Abstract

AbstractStrengthening the interface interaction between metal and support is an efficient strategy to improve the intrinsic activity and reduce the amount of noble metal. Amorphization of support is an effective approach for enhancing the metal‐support interaction due to the numerous surface defects in amorphous structure. In this work, a Pd/a‐MnO2 electrocatalyst containing ultrafine and well‐dispersive Pd nanoparticles and amorphous MnO2 nanosheets is successfully synthesized via a simple and rapid wet chemical method. Differing from the crystal counterpart (Pd/c‐MnO2), the flexible structure of amorphous support can be more favorable to electron transfer and further enhance the metal‐support interaction. The synergism between Pd and amorphous MnO2 results in the downshift of the d‐band center, which is beneficial for the desorption of critical intermediates both in oxygen reduction reaction (ORR) and in ethylene glycol oxidation (EGOR). Due to the lower *.OH desorption energy of Pd/a‐MnO2 surface, the rapid dissociation of *OH from Pd facilitates the formation of H2O in ORR, thus demonstrating superior ORR performance comparable to Pt/C. For EGOR, the presence of amorphous MnO2 promotes the formation of adsorbed OH species, which accelerates the desorption of intermediate CO from Pd sites, and thus exhibits excellent EGOR activity and stability.