Zero-gap bipolar membrane electrolyzer for carbon dioxide reduction using acid-tolerant molecular electrocatalysts

<p>The scaling-up of electrochemical CO₂reduction requires circumventing the CO₂loss as carbonates under alkaline conditions. Zero-gap cell configurations with a reverse-bias bipolar membrane (BPM) represent a possible solution, but the catalyst layer in direct contact with the acidic environment of a BPM usually leads to H₂evolution dominating. Here we show that using acid-tolerant Ni molecular electrocatalysts selective (>60%) CO₂reduction can be achieved in a zero-gap BPM device using a pure water and CO₂feed. At a higher current density (100 mA cm^-2), CO selectivity decreases, but was still >30%, due to reversible product inhibition. This study demonstrates the importance of developing acid-tolerant catalysts for use in large-scale CO₂reduction devices.</p>