(544hc) Electrochemical Cycling Strategy for Selective C­-C Bonded, Acetylene Production from CO2 or CH4 Using Water at Atmospheric Pressure

Carbon dioxide and methane are two major emitted chemicals with global impact as greenhouse gases. The limited demand for these gasses also makes them inexpensive materials. Thus, these gasses are targeted as precursors for chemical processing to produce higher value, more useful products. Aqueous electrochemical CO₂ reduction or CH₄ oxidation are promising routes toward sustainably converting these chemicals into higher value chemicals and fuels. However, CO₂ reduction is often dominated by the hydrogen evolution reaction (HER), with selective routes to very few products like CO, while CH₄ is difficult to selectively oxidize on surfaces and often fully oxidizes to CO₂, if it reacts at all. We have developed an electrochemical cycling strategy as an alternative pathway for CO_2­ reduction and CH₄ oxidation to selectively produce acetylene from either precursor (as well as from CO). The process comprises three distinct steps of electrochemical reactive surface preparation, carbon activation, and acetylene synthesis which can be combined and cycled for continuous acetylene production. This strategy circumvents the HER for CO₂ reduction, and inhibits the complete oxidation to CO₂ for CH₄ oxidation. Acetylene, importantly, is a C-C bonded chemical and fuel with exceptionally diverse chemistry as a chemical precursor to polymers, fuels, and other carbon-based products. Theoretical considerations elucidate the feasibility and general applicability of this cycle and the process steps are characterized with specific electrochemical and materials chemistry techniques. Acetylene is quantified gas chromatography and verified by Fourier transform infrared radiation techniques.