Heterostructure construction of covalent organic frameworks/Ti3C2-MXene for high-efficiency electrocatalytic CO2 reduction

Abstract

Covalent organic frameworks (COFs), as typical organic functional materials, have shown promising potential for application in photo/electrocatalysis, especially in the electrocatalytic CO₂ reduction reaction (CO₂RR). COFs can ensure effective CO₂ adsorption and rapid mass transfer by virtue of controllable active sites and a large specific surface area. However, the inefficient interlayer conductivity of most COFs leads to a low electron transfer rate that restricts their practical applications. In this work, porphyrin-based covalent organic framework nanosheets (Por-COF) were vertically grown on the modified MXene surface for efficient electrocatalytic CO₂RR. The large exposed MXene surface serves as a carrier “bridge” for dispersed COFs, which can endow heterojunctions with more active sites and fast ion transport channels. The optimal sample can exhibit superior efficient CO₂RR performance, in which the faradaic efficiency of the CO₂-to-CO conversion was 97.28% at −0.6 V vs. RHE, and the bias current density was −9.33 mA cm⁻² at −1.0 V vs. RHE.