Multilayer Electrolyzer Stack Converts Carbon Dioxide to Gas Products at High Pressure with High Efficiency.

Electrochemical reduction of CO is a value-added approach to both decrease the atmospheric emission of carbon dioxide and form valuable chemicals. We present a zero gap electrolyzer cell, which continuously converts gas phase CO to products without using any liquid catholyte. This is the first report of a multilayer CO electrolyzer stack for scaling up the electrolysis process. CO formation with partial current densities above 250 mA cm were achieved routinely, which was further increased to 300 mA cm (with ∼95% faradic efficiency) by pressurizing the CO inlet (up to 10 bar). Evenly distributing the CO gas among the layers, the electrolyzer operates identically to the sum of multiple single-layer electrolyzer cells. When passing the CO gas through the layers consecutively, the CO conversion efficiency increased. The electrolyzer provides high partial current density, low cell voltage (-3.0 V), high conversion efficiency (up to 40%), and high selectivity for CO production.