Direct Oxygen Transfer from H 2 O to Cyclooctene over Electron-Rich RuO 2 Nanocrystals for Epoxidation and Hydrogen Evolution.

Production of more than 20 million tons of epoxides per year from olefins suffers from low atom economy due to the use of oxidants and complex catalysts with unsatisfactory selectivity, leading to huge environmental and economic costs. We present a proof-of-concept application of electron-rich RuO 2 nanocrystals to boost the highly selective epoxidation of cyclooctene via direct oxygen transfer from water as the sole oxygen source under mild conditions. The enhanced electron enrichment of RuO 2 nanocrystals via the Schottky effect with nitrogen-doped carbons largely promotes the capture and activation of cyclooctene to give a high turnover frequency (260 h -1 ) of cyclooctene oxide, far surpassing the reported values (<20 h -1 ) of benchmarked catalysts at room temperature with oxidants. Our electron-rich RuO 2 electrocatalysts enable efficient and durable hydrogen production (Faradaic efficiency >90 %) on the cathode without impacting on the selectivity to epoxide (>99 %) on the anode.