Electrochemical generation of syngas from water and carbon dioxide at industrially important rates

•Syngas production from CO2, H2O, and renewable energy.•Electrolysis of CO2 and H2O at commercially viable current densities of 100 mA/cm2.•Electrolysis of H2O at current densities up to 8 A/cm2.•Direct syngas production in a single room-temperature electrolyzer.

The electrochemical production of syngas would enable production of chemicals and transportation fuels from carbon dioxide, water and renewable energy, but a suitable process at the moment does not exist. In this paper we consider two options for syngas production: (i) CO2 electrolysis to produce CO, water electrolysis to produce H2 and then mixing the CO and H2 to yield syngas; and (ii) the simultaneous co-electrolysis of CO2 and H2O in a single electrolyzer. The results show that both processes can produce syngas at industrially important rates. In this paper we demonstrate CO2 electrolysis at 100 mA/cm2, i.e., about 20 turnovers/s, and water electrolysis at 8 A/cm2 at 2.0 V/cell, with about 1,600 turnovers/s. Both systems are stable for a thousand hours or more, i.e., millions of turnovers. We also demonstrate simultaneous CO and H2 production in a single electrolyzer. These results demonstrate that syngas can be produced at industrially important rates via electrolysis.

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