A low cost bimetallic AuCu3 tetramer on Ti2CO2 MXene as an efficient catalyst for CO oxidation: a theoretical prediction

Abstract

Abatement of CO, due to its poisonous nature, is an extensively researched topic. Oxidation to CO₂ is one of the strategies deployed and finds application in automobiles and fuel cells. Gold nanoparticles on an oxide support is a pioneering catalyst in this field, but need improvement in cost, stability, and O₂ activation. Doping with Cu can open up avenues for improvement in these attributes. In the present investigation, we have explored the possibility of using bimetallic Au_nCu_m (n + m = 4) clusters supported on Ti₂CO₂ MXene. We find that AuCu₃ is the most stable cluster on the support. The complete CO oxidation cycle on this supported cluster proceeds through a mix of Langmuir–Hinshelwood (LH) and Eley–Rideal (ER) mechanisms. Our calculations predict that the first cycle is expected to proceed only via the LH mechanism due to kinetic and thermodynamic limitations ascribed to ER and Mars van Krevelen (MvK) mechanisms, respectively. The second cycle, however, prefers ER over the LH mechanism. Overall, with the highest barrier of 0.56 eV, this low cost novel catalyst performs better in terms of stability and/or activity in comparison with many of the catalysts reported in the literature.