Extrinsic Er2O3-inspired H2O adsorption and dissociation on surface of industrial fly ash-derived SiO2 aerogel in electrocatalytic CO2 reduction

Industrial fly ash-derived SiO 2 aerogel with abundant mesopores has an excellent ability to support active ingredients for constructing efficient and stable catalyst in electrochemical CO 2 reduction reaction (CO 2 RR). However, how to select and arrange active sites on its surface poses significant challenges due to its non-conductive nature. Here, we subtly designed and synthesized multi-component architectures to achieve the high efficiency of CO 2 RR to CO. The embedding of active and amorphous nitrogen-doped carbon (NC) nanosheets on the surface and inside of SiO 2 aerogel ensures the charge transport on the catalyst surface, and Er 2 O 3 improves dissociation of H 2 O, enabling the supply of protons for CO 2 RR. Simultaneously, Er 2 O 3 -induced defects/vacancies, nanoclusters coordinated with N on amorphous NC and single Ni in NC play crucial role in enhancing adsorption and activation of CO 2 . Consequently, the Ni-Er 2 O 3 /NC-SiO 2 catalyst exhibits the maintenance of FE CO higher than 95 % over a wide potential window (−0.22 to −1.12 V vs. RHE) in a flow cell with gas-liquid-solid electrode. This work not only provides an atomistic understanding of nature of active sites in CO 2 RR but also contributes to the secondary utilization of industrial fly ash for a carbon-neutral future.