Zero-crossover electrochemical CO2 reduction to ethylene with co-production of valuable chemicals
Mohd Adnan Khan, Shariful Kibria Nabil, Tareq A. Al‐Attas, Nael Yasri, Soumyabrata Roy, Muhammad M. Rahman, Steve Larter, Pulickel M. Ajayan, Jinguang Hu, Md Golam Kibria
Abstract
To date, electrochemical reduction of CO2 (eCO2R) is plagued by undesirable carbonate formation and crossover that adds an energy penalty. Using a bipolar membrane, copper cathode, and gold nano-dendrite (Au-ND) anode, we report eCO2R to C2H4 on cathode coupled with glycerol oxidation on anode with zero carbonate crossover. The co-electrolysis system operated at high current densities of 175–225 mA/cm2 and C2H4 faradaic efficiency (FE) of 50%. The full cell voltages were between 3.9 and 4.4 V, which represented a decrease of 0.8 V versus conventional eCO2R. In addition, the Au-ND catalyst demonstrated high FE of 50% for glycolic acid (GA) production, which helped drive economic feasibility of the process. Our techno-economic analysis indicated that, while it would be improbable to commercialize a conventional eCO2R-to-C2H4 process, a co-electrolysis process to produce C2H4 from CO2 and GA from crude glycerol, with zero carbonate crossover, can attain a competitive minimum selling price (MSP) of C2H4 ∼$1.1/kgC2H4.