Scaled CO Electroreduction to Alcohols
Panagiotis Papangelakis, Colin P. O’Brien, Ali Shayesteh Zeraati, Shijie Liu, Alexander Paik, Vivian E. Nelson, Sungjin Park, Yurou Celine Xiao, Roham Dorakhan, Puhua Sun, Jinhong Wu, Christine M. Gabardo, Ning Wang, Rui Kai Miao, Edward H. Sargent, David Sinton
Abstract
Electrocatalysis offers a promising route to convert CO2 into alcohols, which is most efficient in a two-step cascade reaction with CO2-to-CO followed by CO-to-alcohol. However, current alcohol-producing CO2/CO electrolyzers suffer from low selectivity or alcohol crossover, resulting in alcohol concentrations of less than 1%, which are further diluted in downstream cold-traps. As a result, electrocatalytic alcohol production has yet to be scaled beyond the lab (1-10 cm2). Here, we reverse the electroosmotic drag of water using a cation exchange membrane assembly, enabling the recovery of over 85% of alcohol products at a concentration of 6 wt.%. We develop a multi-step condenser strategy to separate the produced alcohols from the effluent gas stream without dilution. Scaling up this approach to an 800 cm2 cell resulted in an output of 200 mL alcohol/day. The electrocatalytic upgrading of CO2/CO provides a promising route to produce carbon-neutral alcohols but suffers from product loss to crossover and dilution. Here, the authors report on a CO reduction electrolyzer that recovers over 85% of alcohol without dilution, which is then scaled to 800 cm2.