Ag/Zn-Ta2C MXene composite as an efficient electrocatalyst for aqueous and non-aqueous CO2 reduction reactions

Abstract

This study reports the preparation of an Ag and Zn-based Ta2CTx MXene composite and its electrocatalytic application towards the electrochemical CO2RR in aqueous and non-aqueous (organic) solvents. In aqueous 0.1 M KHCO3, Ag and Zn-based Ta2CTx MXene cathode enables efficient conversion of CO2 to valuable products such as syngas (CO:H2) and formic acid. Ag/Ta2CTx MXene-modified electrode, exhibiting the best CO and H2 (1:1) selectivity at an applied potential of − 0.65 V vs. RHE syngas, was collectively found to be ~ 80%, whereas at the same potential, some formate (20%) was formed. Similar to Zn/Ta2CTx, MXene showed the highest selectivity for CO of 83%. By employing a divided cell setup, CO2RR occurs at lower reduction potentials, enhancing the feasibility of the process. In non-aqueous media, styrene was electrocarboxylated to phenylsuccinic acid (PSA) and phenylpropanoic acid (PPA) using the same cathode, and the selectivity varies Ag/Ta2CTx MXene (45% of PSA) and Zn/Ta2CTx (41% of PPA) with respect to the metal ion present in the composite. Mono- and di-carboxylic acids were produced in quantifiable amounts using the MXene-modified electrodes as the cathode and sacrificial aluminum as the anode. This work highlights the potential of MXene-based electrocatalysts for aqueous CO2RR and selective electrocarboxylation, offering promising pathways for sustainable fuel production and chemical synthesis.