Selective CO2 electrocatalysis at the pseudocapacitive nanoparticle/ordered-ligand interlayer

Enzymes feature the concerted operation of multiple components around an active site, leading to exquisite catalytic specificity. Realizing such configurations on synthetic catalyst surfaces remains elusive. Here, we report a nanoparticle/ordered-ligand interlayer that contains a multi-component catalytic pocket for high-specificity CO2 electrocatalysis. The nanoparticle/ordered-ligand interlayer comprises a metal nanoparticle surface and a detached layer of ligands in its vicinity. This interlayer possesses unique pseudocapacitive characteristics where desolvated cations are intercalated, creating an active-site configuration that enhances catalytic turnover by two orders and one order of magnitude against a pristine metal surface and nanoparticle with tethered ligands, respectively. The nanoparticle/ordered-ligand interlayer is demonstrated across several metals with up to 99% CO selectivity at marginal overpotentials and onset overpotentials of as low as 27 mV, in aqueous conditions. Furthermore, in a gas-diffusion environment with neutral media, the nanoparticle/ordered-ligand interlayer achieves nearly unit CO selectivity at high current densities (98.1% at 400 mA cm−2).