Improving the Stability, Selectivity, and Cell Voltage of a Bipolar Membrane Zero‐Gap Electrolyzer for Low‐Loss CO ₂ Reduction

Electrolyzers for CO2 reduction containing bipolar membranes (BPM) are promising due to low loss of as carbonates and product crossover, but improvements in selectivity, stability, cell voltage required. In particular, direct contact with the acidic cation exchange layer leads high levels H2 evolution many common cathode catalysts. Here, Co phthalocyanine (CoPc) is reported a suitable catalyst zero-gap BPM device, reaching 53% Faradaic efficiency CO at 100 mA cm−2 using only pure water input feeds. It also shown that can be lowered by constructing customized TiO2 dissociation catalyst, however this cost decreased selectivity. Switching pure-water anolyte KOH improved both selectivity (62% 200 cm−2), crossover could cause complications. The results demonstrate viable strategies improving electrolyzer toward practical-scale CO2-to-chemicals conversion.