Tailoring the Catalytic Microenvironment of Cu 2 O with SiO 2 to Enhance C 2+ Product Selectivity in CO 2 Electroreduction

作者：Tete Zhao, Jinhan Li, Jiuding Liu, Fangming Liu, Keqiang Xu, Meng Yu, Wence Xu, Fangyi Cheng · 发表于：ACS Catalysis · 年份：2023 · DOI：10.1021/acscatal.3c00056 · 被引用次数：132 · 研究领域：CO2 Reduction Techniques and Catalysts、Ionic liquids properties and applications、Advanced Thermoelectric Materials and Devices

Achieving high activity and selectivity of multicarbon products in the CO 2 reduction reaction (CO 2 RR) on Cu-based electrocatalysts remains challenging due to the limited concentration of local OH –, sluggish CO 2 diffusion, and competitive hydrogen evolution reaction. Herein, we report aerophilic nanocomposites of hydrophobic SiO 2 aerosol and Cu 2 O nanocubes to tailor the microenvironment for enhancing CO 2 electroreduction in 0.1 M KHCO 3 aqueous electrolyte. Combined in situ infrared analysis, molecular dynamics simulations, and density functional theory calculations reveal that the composite Cu 2 O/SiO 2 enriches the local hydroxyl by blocking the reaction between OH – and HCO 3 –, accelerates CO 2 diffusion coefficient (from 2.67 × 10 –10 to 8.46 × 10 –10 m 2 s –1 ), and renders a lower dissociation energy of H 2 O than bicarbonate (0.49 vs 1.24 eV on Cu 2 O (111)) as compared to neat Cu 2 O. Consequently, Cu 2 O/SiO 2 promotes the formation of C 2+ products (Faradaic efficiency FE C2+ from 52.4 to 75.6%) and suppresses hydrogen generation (FE H2 from 30.0 to 9.6%) at −1.2 V versus reversible hydrogen electrode. The results provide insight into the selectivity improvement of CO 2 RR electrocatalysis by regulating the local microenvironment of alkalinity, H 2 O transportation, and CO 2 permeability.