Convergent Electrochemical-Chemical Tandem Catalysis Synthesis of Ethylene Oxide from CO and Water at Ambient Conditions.

Ethylene oxide (EO) is an important commodity chemical, and its production currently relies on fossil fuel-based energy-intensive thermocatalysis associated with substantial CO emissions or the usage of toxic/corrosive precursors (e.g., Cl). Herein, we report a convergent electrochemical-chemical tandem route for efficient synthesis of EO from CO and water under ambient conditions over nonprecious catalysts. Such a protype consists of cathodic CO electroreduction to CH and simultaneous anodic two-electron water electrooxidation (2e-WOR) to HO in a single electrolyzer, followed by reaction of the two products over titanium silicalite-1 (TS-1) catalyst toward EO with high production rate of 422.3 µmol h and high selectivity of >98%. W-doped CuO and Cu-doped SnO were used as cathode and anode electrodes with respective Faradaic efficiencies of 63.5% and 75.6% at 800 mA cm. Systematic characterizations, including Sn Mössbauer spectroscopy, quasi-in situ electron paramagnetic resonance (EPR), isotope-labeling mass spectrometry (MS), and operando infrared spectroscopy, along with theoretical calculations, reveal that Cu doping breaks the electronic structure symmetry of Sn to induce electron redistribution for optimal adsorption and coupling of key intermediates like *OH in 2e-WOR. This study offers a sustainable manner for efficient EO synthesis from raw materials with renewable electricity input.