Probing the reactivity of in situ formed oxygen vacancies of non-noble lead oxides for anodic propylene oxidation

Abstract

Electrochemical oxidation of propylene into value-added products represents a promising strategy for producing commodity chemicals using renewable electricity, thereby aligning with the goals of sustainable chemical manufacturing. While noble metal-based catalysts (e.g., Pd- and Pt-based metal oxides) have been extensively studied for this reaction, the possibility of using non-noble metal-based catalysts and their mechanism remained largely unknown. Herein, we provide the first-ever experimental demonstration of using stable non-noble metal oxide catalysts (i.e., PbO₂) for this reaction, and investigate the reaction mechanism of electrochemical propylene oxidation. Electrochemical in situ attenuated total reflection Fourier transform infrared spectroscopy reveals the formation of key surface-bound intermediates during the propylene oxidation process. Moreover, in situ differential electrochemical mass spectrometry confirms the active participation of lattice oxygen in the reaction, suggesting a lattice oxygen-mediated mechanism. These findings shed light on the reaction pathways of non-noble metal catalysts and provide valuable guidance for the rational design of cost-effective and highly selective electrocatalysts for electrochemical alkene oxidation.