Enhanced Multicarbon Production via Pulsed Syngas Electroreduction on Ag-Decorated ZnO Nanoparticles

Sustainable multicarbon production through syngas electroreduction is particularly attractive, as products such as ethanol, acetaldehyde, and ethylene offer significantly higher economic value and broader functional applications than single-carbon products. In this study, Ag/ZnO nanoparticles were synthesized and characterized with high-resolution transmission electron microscopy (TEM) coupled with an electron energy loss spectroscopy (EELS) detector to confirm the nanoparticles size in the 10 nm range, in which Ag nanoparticles were located on the surface of ZnO nanoparticles. The electrocatalytic activity of Ag/ZnO nanoparticles was enhanced by the effective electron transfer between ZnO and Ag, promoting the multicarbon Faradaic efficiency (FE) from (8 ± 1)% for ZnO to (17 ± 3)% for ZnAg1.5 over 10 min of chronopotentiometry. Operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and X-ray photoelectron spectroscopy (XPS) directly linked this enhancement to dynamic surface chemistry, revealing ZnO as the primary active site, while Ag can facilitate electron transfer and stabilize reaction intermediates. Both techniques also suggested that surface-adsorbed water/OH– can act as a catalyst deactivator, leading to catalyst dissolution. Based on these insights, the potential was pulsed between 0.82 and −0.63 V vs RHE to remove accumulated water/OH– and regenerate active sites. This increased the single-pass FE to (54 ± 5)% with (37 ± 2)% selectivity toward ethanol. Together, these results demonstrate that rational interface design combined with dynamic potential modulation offers a powerful strategy for advancing syngas to multicarbon electrocatalysis.