Selective electrochemical reduction of carbon dioxide to ethanol via a relay catalytic platform.

Efficient electroreduction of carbon dioxide (CO2) to ethanol is of great importance, but remains a challenge because it involves the transfer of multiple proton-electron pairs and carbon-carbon coupling. Herein, we report a CoO-anchored N-doped carbon material composed of mesoporous carbon (MC) and carbon nanotubes (CNT) as a catalyst for CO2 electroreduction. The faradaic efficiencies of ethanol and current density reached 60.1% and 5.1 mA cm-2, respectively. Moreover, the selectivity for ethanol products was extremely high among the products produced from CO2. A proposed mechanism is discussed in which the MC-CNT/Co catalyst provides a relay catalytic platform, where CoO catalyzes the formation of CO* intermediates which spill over to MC-CNT for carbon-carbon coupling to form ethanol. The high selectivity for ethanol is attributed mainly to the highly selective carbon-carbon coupling active sites on MC-CNT.