Tunable CO2 enrichment on functionalized Au surface for enhanced CO2 electroreduction
Huimin Wang, Yuqing Fu, Zhe‐Ning Chen, Wei Zhuang, Minna Cao, Rong Cao
Abstract
Electrochemical conversion of carbon dioxide (CO2) to higher-value products provides a forward-looking way to solve the problems of environmental pollution and energy shortage. However, the low solubility of CO2 in aqueous electrolytes, sluggish kinetics, and low selectivity hamper the efficient conversion of CO2. Here, we report a Au-based hybrid nanomaterial by modifying Au nanoparticles (NPs) with the macrocyclic molecule cucurbit[6]uril (Au@CB[6]). Au@CB[6] displays the optimal selectivity of CO, with the highest CO Faraday efficiency (FECO) reaching 99.50% at −0.6 V vs. reversible hydrogen electrode (RHE). The partial current density of CO formed by Au@CB[6] increases dramatically, as 3.18 mA/cm2 at −0.6 V, which is more than ten times as that of oleylamine-coated Au NPs (Au@OAm, 0.31 mA/cm2). Operando electrochemical measurement combined with density functional theory (DFT) calculations reveals that CB[6] can gather CO2 and lead the increased local CO2 concentration near metal interface, which realizes significantly enhanced electrochemical CO2 reduction reaction (CO2RR) performance.