Reasonable Design of MXene-Supported Dual-Atom Catalysts with High Catalytic Activity for Hydrogen Evolution and Oxygen Evolution Reaction: A First-Principles Investigation

Abstract

MXene-supported single-atom catalysts (SACs) for water splitting has attracted extensive attention. However, the easy aggregation of individual metal atoms used as catalytic active centers usually leads to the relatively low loading of synthetic SACs, which limits the development and application of SACs. Herein, by performing first-principles calculations for Pt and 3d transition metal single atoms immobilized on a two-dimensional (2D) Mo2TiC2O2 MXene surface, we systematically studied the performance of heterogeneous dual-atom catalysts (h-DACs) in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Significantly, h-DACs exhibit higher metal atom loading and more flexible active sites compared to SACs. Benefiting from these features, we found that Pt/Cu@Mo2TiC2O2 heterogeneous DACs exhibits excellent HER activity with ultra-low overpotential |ΔGH∗| (0.04 eV), lower than the corresponding Pt@Mo2TiC2O2 (0.14 eV) and Cu@Mo2TiC2O2 (0.33 eV) SACs, and even lower than that of Pt (0.09 eV). Meanwhile, Pt/Ni@Mo2TiC2O2 exhibits superior OER activity with ultra-low overpotential ηOER (0.38 V), lower than that of Pt@Mo2TiC2O2 (1.11 V) and Ni@Mo2TiC2O2 (0.57 V) SACs, and even lower than that of RuO2 (0.42 V) and IrO2 (0.56 V). Our finding paves the way for the rational design of h-DACs for HER and OER with excellent activity, which provides guidance for other catalytic reactions.

Oxygen defect engineering on low-crystalline iron(iii) oxyhydroxide as a highly efficient electrocatalyst for water oxidation

“…S27 and S28†) based on the Δ G change of the 4e − pathway to elucidate the water oxidation energy barrier of V O -FeOOH and FeOOH counterpart. 53 The OER process of the widely accepted AEM mechanism can be divided into four stages, including three intermediate states (OH*, O*, and OOH*) (Fig. 5d).…”

“…51,52 Then we continue to study the OER catalytic activity of V O -FeOOH, and further calculate the different models (Fig. S27 53 The OER process of the widely accepted AEM mechanism can be divided into four stages, including three intermediate states (OH*, O*, and OOH*) (Fig. 5d).…”

MBenes-supported single-atom catalysts for oxygen reduction and oxygen evolution reactions by first-principles study and machine learning

“…g and l denote the gas phase and liquid phase, respectively. OER can be regarded as the reverse reaction process of ORR, which is composed of the following four corresponding elementary steps [41]: In order to evaluate the ORR catalytic activity, it is necessary to calculate the Gibbs free energy change (∆G) of each elementary step. According to the computational hydrogen electrode (CHE) model proposed by Nørskov et al [9], the general formula of ∆G can be described as the following equation for each elementary step.…”

In situ self-reconstructed hierarchical bimetallic oxyhydroxide nanosheets of metallic sulfides for high-efficiency electrochemical water splitting

“…72,73 We further examined the OER catalytic activity of FeCoOOH and clarified the water oxidation energy barriers for FeCoOOH, CoOOH, and FeOOH based on DG changes along the 4e À pathway. 74 The widely acknowledged AEM mechanism for the OER process can be categorized into four stages, encompassing three intermediate states (*OH, *O, *OOH) (Fig. 6e).…”