The coordination of Al on pyridinic-N doped graphene as electrons reservoir for efficiently catalyzing CO oxidization

Abstract Single atom catalysts (SACs) have gained paramount attention due to their superior catalytic reactivity. Herein, as the most abundant metal on earth, the aluminum (Al) was used to construct a novel SAC with configuration of Al-GN4 for catalytic oxidation of CO, where a single Al atom was coordinated with four pyridinic nitrogen atoms doped in graphene grids. Four CO catalytic oxidization mechanisms including Eley-Rideal (ER), Langmuir-Hinshelwool (LH), New Eley-Rideal (NER) and termolecular Eley-Rideal (TER) were investigated to explore the catalytic performance of Al-GN4. It was found that the energy barriers of the rate-determining step for ER, LH and NER mechanisms were in the range from 0.41 to 0.59 eV, denoting the high catalytic activity of Al-GN4. It is worthy to note that the CO oxidization via TER mechanism is nearly barrierless although the probability may be low for its high adsorption energy at the initial state. Through detailed electronic structure analysis, an Al-N-C local structure functioning as electrons reservoir for electrons collection and release during adsorption and activation of O2 was proposed. Our results may provide clues for understanding the catalytic performance of SACs, moreover, we expect it will be helpful for designing other SACs with superior activity.