Carboxyl-functionalized carbon nanotubes coordinated with two-dimensional bimetallic porphyrin-based CuMOFs for efficient electrocatalytic CO2 reduction

Abstract

The focus on electrocatalytic CO2 reduction to lessen surplus CO2 emissions and counteract the greenhouse effect has intensified. The synergistic combination of metal-organic frameworks (MOFs) and carbon-based materials has emerged as a potentially effective method to enhance electron transfer efficiency. In this study, we created a Cu-(Co+Cu)PMOF/CNT-COOH hybrid by integrating a two-dimensional bimetallic porphyrin-based CuMOF with carboxyl-modified carbon nanotubes. When compared with (Co+Cu)PMOF/CNT, which is formed through weak π-π interaction, our hybrid demonstrates superior stability, additional exposed active sites, and a higher electron transfer rate from CNT-COOH to Cu-(Co+Cu)PMOF, resulting in improved electrocatalytic action for CO2 reduction. Electrochemical tests indicate that the Cu-(Co+Cu)PMOF/CNT-COOH hybrid achieves a CO faradic efficiency of 95.98% with an impressive current density of -3.48 mA‧cm-2 at an overpotential of -0.9 V vs. RHE, significantly outperforming single metal porphyrin-based CuMOF counterparts. This research offers fresh perspective on how to thoughtfully construct high-performance electrocatalytic hybrid materials for CO2 reduction.