Synergistic regulation of hydrophobicity and basicity for copper hydroxide‐derived copper to promote the CO2 electroreduction reaction

Abstract

Abstract A simple method was proposed to activate alkaline Cu(OH)2 with an acidic ionomer, Nafion, to regulate its surface microenvironment, including hydrophobicity and local basicity. In particular, the direct complete neutralization reaction between Cu(OH)2 and Nafion in aqueous solution induces the exposing of vast anions which can exclude the in‐situ‐formed hydroxides and raise the local basicity. Remarkably, the optimal Nafion‐activated Cu(OH)2‐derived Cu can efficiently suppress the hydrogen evolution reaction (HER) and improve the selectivity for multi‐carbon products in the CO2 electroreduction reaction (eCO2RR). The H2 Faradaic efficiency (FE) decreased to 11% at a current density of 300 mA/cm2 (−0.76 V vs. RHE) in a flow cell, while the bare one with H2 had an FE of 40%. The total eCO2RR FE reaches as high as 83%, along with an evidently increased C2H4 FE of 44% as compared with the bare one (24%), and good stability (8000 s), surpassing that of most of the reported Cu(OH)2‐derived Cu. The experimental and theoretical results both show that the strong hydrophobicity and high local basicity jointly boosted the eCO2RR as acquired by felicitously introducing ionomer on the Cu(OH)2‐derived Cu surface.

Keywords

• CO2 electroreduction reaction
• Cu(OH)2@Nafion
• flow cell
• ionomers
• multi‐carbon products