Boosting Selective Oxidation of Ethylene to Ethylene Glycol Assisted by In situ Generated H₂O₂ from O₂ Electroreduction

Abstract

Ethylene glycol is a useful organic compound and chemical intermediate for manufacturing various commodity chemicals of industrial importance. Nevertheless, the production of ethylene glycol in a green and safe manner is still a long-standing challenge. Here, we established an integrated, efficient pathway for oxidizing ethylene into ethylene glycol. Mesoporous carbon catalyst produces H₂ O₂ , and titanium silicalite-1 catalyst would subsequently oxidize ethylene into ethylene glycol with the in situ generated H₂ O₂ . This tandem route presents a remarkable activity, i.e., 86 % H₂ O₂ conversion with 99 % ethylene glycol selectivity and 51.48 mmol g_ecat ^-1 h^-1 production rate at 0.4 V vs. reversible hydrogen electrode. Apart from generated H₂ O₂ as an oxidant, there exists ⋅OOH intermediate which could omit the step of absorbing and dissociating H₂ O₂ over titanium silicalite-1, showing faster reaction kinetics compared to the ex situ one. This work not only provides a new idea for yielding ethylene glycol but also demonstrates the superior of in situ generated H₂ O₂ in tandem route.