Heterogeneous Co1/P1Mo12O40 single-atom catalyst for CO oxidation via termolecular Eley-Rideal (TER) mechanism

Abstract

Catalytic mechanisms, micro-kinetic and thermodynamics studies of Phosphomolybdic acid (PMA) supported non-noble metal (NNM1 = Sc1, Ti1, V1, Cr1, Mn1, Fe1, Co1, Ni1, Cu1, and Zn1) single-atom catalysts (SACs) are explored for carbon monoxide (CO) oxidation by using DFT calculations. The results reveal that Co1/P1Mo12O40 have demonstrated excellent ability to adsorb (CO, O2) molecules, resulting in significant charge transfer from the catalyst surface to the adsorbate, which is essential to produce CO2 under normal reaction conditions. The various reaction pathways, including Eley Rideal (ER), Langmuir Hinshelwood (LH), Termolecular Eley Rideal (TER), and Mars Van Krevelen (MvK) are explored for CO oxidation on Co1/P1Mo12O40 to authenticate the most auspicious reaction mechanism. The energy barrier for the TER mechanism was 0.41 eV, lower as compared to the other reported materials which suggests that the Co1/P1Mo12O40 SACs would be the most appropriate future material for CO oxidation. To further validate the results, we performed the microkinetic investigation which predicts the CO oxidation rate of 4.58 × 106 s − 1. The key role of spin-magnetic moment for the promotion of CO oxidation by using Co1 single-atom catalyst was revealed from the deep electronic analysis. The current results would provide appreciated guidelines for experimentalists to develop less expensive and more effective non-noble metal SACs for CO oxidation.