The formation and evolution of carbonate species in CO oxidation over mono-dispersed Fe on graphene

Abstract

Fe is not only the most abundant metal on the planet, but also the key component of many enzymes in organisms that are capable to catalyze many chemical conversions. Mono-dispersed...

Coadsorption Interfered CO Oxidation over Atomically Dispersed Au on h-BN

“…The calculated CO 2 E ad for CO 2 physisorption on AuO (LHd-IS1, Figure 5 a) is −0.07 eV and the corresponding ΔG is 0.51 eV. These are in reasonable agreement with Pd, Fe and Au SACs on graphene [ 31 , 55 , 56 ]. In LHd-IS1, both the C-O bonds are nearly vertical to C(CO 2 )-O(Au) direction.…”

“…The van de Waals complexes formed between preadsorbed CO or O 2 with gaseous reactants, such as AuO 2 + CO(g), Au(CO) 2 + O 2 (g), etc., are less plausible as compared with the corresponding surface species, such as AuO 2 + CO, etc., while Au(CO) 2 + O 2 is unstable and O 2 may desorb during structure optimization. The superior stability of reaction species on LH type pathways over those van de Waals complexes were previously reported for in CO oxidation over other SACs, where the relative stability among these reaction species were proposed to account for the dominant role of the rLH pathway in the CO oxidation [ 55 , 56 ]. Further to these, the charge transfer from activated O 2 to CO is required for the formation of CO 3 intermediate on the ER2 pathway, and a reaction of this kind is always accompanied with high reaction barriers.…”

“…We recently investigated CO oxidation over the defect-stabilized Fe and Pd SACs on graphene and demonstrated that the coadsorption of CO and O 2 would be more plausible on these SACs over van de Waals complexes and the coadsorption of 2 CO to initiate CO oxidation on ER type pathways. Thus, it would be a major reaction species with a population superior to those van de Waals complexes and is the active species to initiate CO oxidation [ 55 , 56 , 81 ]. The calculated thermodynamics stability of reaction species on AuBN ( Figure 1 j) also demonstrated such a trend that AuO 2 + CO is more plausible than AuO 2 + CO(g) and Au(CO) 2 , though AuCO is the most plausible species in reaction conditions.…”

“…This pathway also connects the evolution of OCOO to thermodynamically more plausible CO 3 species and solves the concern for formation and evolution of CO 3 species in CO oxidation on SACs [ 73 , 74 , 75 , 85 ]. We then moved on to investigate the potential coadsorption with CO and whether CO may promote the conversion of CO 3 [ 56 ]. The CO coadsorption leads to the formation of LHd-MS2 ( Figure 5 d).…”

“…Recently, we theoretically explored the reaction network for CO oxidation over Pd 1 and Fe 1 SACs on graphene and highlighted the vital role of the thermostability of reaction species in determining CO conversion and reaction pathways [ 55 , 56 ]. In this work, we focus on CO oxidation over AuBN to highlight the impact of coadsorbed substrates to the formation and evolution of surface species on SACs in reaction conditions with extensive first-principles-based calculations.…”