Interparticle Distance Matters for Selectivity Control in Industrially Relevant CO Electrolysis

While catalytic performances are usually sensitive to catalyst surface structures at the nanoscale and atomic scale, crucial factors affecting species transport at the mesoscale are often overlooked. Here we reveal the role of interparticle distance in tuning product selectivity in CO electrolysis at industrially relevant current densities using model Cu nanoparticle gas diffusion electrodes with tunable average interparticle distances. Increasing the average interparticle distance of Cu nanoparticles remarkably increases the selectivity toward acetate, a specific multicarbon product. Experimental and numerical calculation results indicate that a larger interparticle distance increases the local pH near Cu nanoparticles and the local CO concentration owing to weakened interparticle CO diffusion at the mesoscale. By coupling external reaction conditions, the maximum acetate Faradaic efficiency and partial current density reach 77.5% and 705 mA cm–2, respectively. Our findings illustrate the importance of interparticle distance as a mesoscopic descriptor for selectivity control in complex catalytic reactions under industrially relevant conditions.