V activated electro-epoxidation catalyst in membrane electrode assembly system for the production of propylene oxide
Yan Lin, Hui Li, Xiaodong Miao, Yunayuan Sun, Hao Ren, Xifeng Yu, Wangyang Cui, Mingbo Wu, Zhongtao Li
Abstract
Direct electro-epoxidation of propylene (D-EOPO) with a membrane electrode assembly (MEA) system represents a sustainable approach for producing propylene oxide, which can reduce ohmic losses and simplify product separation. To address the challenges of selectivity and activity, we develop an Ag/V catalyst and integrate it into the “liquid-free” MEA reactor for continues D-EOPO. The V in the catalyst facilitates the formation of Ag-O active centers, thereby reducing the generation energy of *O radicals. Meanwhile, V doping also results in a downshift of the d-band center of the Ag sites. Consequently, the formation of the crucial intermediate (*OC3H6) is significantly accelerated through the coupling *O with adsorbed propylene, thereby markedly improving propylene oxide (PO) production. The MEA reactor, integrated with the developed Ag/V catalyst, can maintain a stable production rate of PO at 227 μmol/h over a period of 78 hours. Thus, the “liquid-free” electro-epoxidation protocol developed here exhibits greater industrial applicability. Conventional propylene epoxidation uses corrosive oxidants, facing separation issues and instability. Here, the authors report an Ag-V catalyst in membrane electrode assembly system for propylene oxide production via direct electro-epoxidation, eliminating oxidants and enabling instant separation.