Triggering Lattice Oxygen Activation of Single‐Atomic Mo Sites Anchored on Ni–Fe Oxyhydroxides Nanoarrays for Electrochemical Water Oxidation

Abstract

Tuning the reactivity of lattice oxygen is of significance for lowering the energy barriers and accelerating the oxygen evolution reaction (OER). Herein, single‐atomic Mo sites are anchored on Ni–Fe oxyhydroxide nanoarrays by a facile metal–organic‐framework‐derived strategy, exhibiting superior performance toward the OER in alkaline media. In situ electrochemical spectroscopy and isotope‐labeling experiments reveal the involvement of lattice oxygen during OER cycles. Combining theoretical and experimental investigations of the electronic configuration, it is comprehensively confirmed that the incorporation of single‐atomic Mo sites enables higher oxidation state of the metal and strengthened metal–oxygen hybridization, as well as the formation of oxidized ligand holes above the Fermi level. In a word, the considerable acceleration of water oxidation is achieved via enhancing the reactivity of lattice oxygen and triggering the lattice oxygen activation. This work may provide new insights for designing ideal electrocatalysts via tuning the chemical state and activating the anions ligands.

Electronic Modulation of the Interaction between Fe Single Atoms and WO2.72–x for Photocatalytic N2 Reduction

“…There are three desorption peaks in the N 2 -TPD profile of pristine WO 2.72 , which can be assigned to N 2 physisorption the Fe single atom is anchored on the WO 2.72−x surface, there is delocalization of electrons across the Fe−O bond (Figure S13), which denotes high covalency 50 favorable to the state transition of interfacial electrons and acceleration of charge transfer. 51 The above results indicate that an electron transfer channel is created between the Fe-SA/WO 2.72−x surface and the adsorbed N 2 , enabling the Fe single atom to be the active site for N 2 activation. The photophysical and charge transfer properties of Fe-SA-4/WO 2.72−x were studied in detail.…”

“…The differential charge densities of Fe-SA/WO 2.72– x with N 2 adsorption clearly show that the N 2 molecule obtains electrons from WO 2.72– x and is activated (Figure e). In addition, the pictures of the electron localization function (ELF, Figure f,g) indicate that when the Fe single atom is anchored on the WO 2.72– x surface, there is delocalization of electrons across the Fe–O bond (Figure S13), which denotes high covalency favorable to the state transition of interfacial electrons and acceleration of charge transfer . The above results indicate that an electron transfer channel is created between the Fe-SA/WO 2.72– x surface and the adsorbed N 2 , enabling the Fe single atom to be the active site for N 2 activation.…”

Spatial Relation Controllable Di‐Defects Synergy Boosts Electrocatalytic Hydrogen Evolution Reaction over VSe2 Nanoflakes in All pH Electrolytes

“…Additionally, the pre-edge peak located at ≈20 003 eV corresponds to the dipole-allowed 1s → 4d transition, implying tetrahedral symmetry of Mo single atoms. [49] Besides, the weak shoulder peak at ≈20 023 eV was attributed to local tetrahedral unit cell configuration distortion. [50] The Fourier transform extended X-ray absorption fine structure spectra of the Mo K-edge displays the first-shell signal at 2.19 Å (Figure 3f), corresponding to the Mo-Se bonds of the V 0.8 Mo 0.2 Se 2 nanosheets.…”

Self-Supporting Metal-Organic Framework-Based Nanoarrays for Electrocatalysis

“…Earth-abundant transition metal oxides or hydroxides as one of the most promising candidates for OER have been extensively investigated due to their good cost-effectiveness and ease of preparation. − However, their catalytic performance is usually inhibited by the inherent poor conductivity, slow mass transport, and inadequate active sites. , In this regard, MOF used as a template or precursor to derive nanoarray-structured oxides or hydroxides can effectively relieve these issues and is extremely attractive for improving OER activity. − For example, Kong et al fabricated a 3D self-branching ZnCo 2 O 4 @N-doped carbon hollow nanowall arrays on carbon textiles (ZnCo 2 O 4 @NC/CTs) through controlled cation exchange and postannealing processes (Figure d) . The as-prepared ZnCo 2 O 4 @NC/CTs electrode exhibited favorable catalytic activity and OER kinetics (Figure e,f), which can be attributed to the following reasons.…”