Designing novel single-atom catalysts (SACs) supports to modulate the electronic structure is crucial to optimize the catalytic activity, but rather challenging. Herein, a general strategy is proposed to utilize the metalloid properties of supports to trap and stabilize single-atoms with low-valence states. A series of single-atoms supported on the surface of tungsten carbide (M-WCx, M=Ru, Ir, Pd) are rationally developed through a facile pyrolysis method. Benefiting from the metalloid properties of WCx, the single-atoms exhibit weak coordination with surface W and C atoms, resulting in the formation of low-valence active centers similar to metals. The unique metal-metal interaction effectively stabilizes the low-valence single atoms on the WCx surface and improves the electronic orbital energy level distribution of the active sites. As expected, the representative Ru-WCx exhibits superior mass activities of 7.84 and 62.52 A mgRu−1 for the hydrogen oxidation and evolution reactions (
Hydrogen-evolution-reaction
Hydrogen-oxidation-reaction
Low-valence
Metal-carbides
Single-atom-catalysts
Superior catalyst supports are crucial to developing advanced electrocatalysts toward heterogeneous catalytic reactions. Herein, we systematically investigate the role of transition metal-functionalized N-doped carbon nanosheets (M-N-C, M = Mn, Fe, Co, Ni, Cu, Mo, and Ag) as the multifunctional electrocatalyst supports toward hydrogen evolution/oxidation reactions (HER/HOR) in alkaline media. The results demonstrate that all the M-N-C nanosheets, except Cu-N-C and Ag-N-C, can promote the alkaline HER/HOR electrocatalytic activity of Pt by accelerating the sluggish Volmer step, among which Mn plays a more significant role. Analyses reveal that the promotion effect of M-N-C support is closely associated with the electronegativity of the metal dopants and the relative filling degree of their d-orbitals. For one, the metal dopant in M-N-C with smaller electronegativity would provide more electrons to oxygen and hence tune the electronic structure of Pt via the M-O-Pt bonds at the interface
Electrocatalysis
Hydrogen-evolution-reaction
Hydrogen-oxidation-reaction
Etal-support-interaction
Ultifunctional-support
Abstract
Boosting the alkaline hydrogen evolution and oxidation reaction (HER/HOR) kinetics is vital to practicing the renewable hydrogen cycle in alkaline media. Recently, intensive research has demonstrated that interface engineering is of critical significance for improving the performance of heterostructured electrocatalysts particularly toward the electrochemical reactions involving multiple reaction intermediates like alkaline hydrogen electrocatalysis, and the research advances also bring substantial non-trivial fundamental insights accordingly. Herein, we review the current status of interface engineering with respect to developing efficient heterostructured electrocatalysts for alkaline HER and HOR. Two major subjects how interface engineering promotes the reaction kinetics and what fundamental insights interface engineering has brought into alkaline HER and HOR are discussed. Specifically, heterostructured electrocatalysts with abundant interfaces have shown substantially
Electrocatalysis
Heterostructure
Hydrogen-evolution-reaction
Hydrogen-oxidation-reaction
Interface-engineering
Abstract
Developing non-platinum group metal (non-PGM) electrocatalysts for the hydrogen oxidation reaction (HOR) represents the efforts towards the more economical use of hydrogen fuel cells and hydrogen energy, which has attracted tremendous attention recently. However, non-PGM electrocatalysts for the HOR are still in their early development stages as compared with the significant advances in those for the oxygen reduction reaction and hydrogen evolution reaction. Herein, this paper summarizes the recent progresses and highlights the key challenges for the rational design of non-PGM electrocatalysts, aiming to promote the development of non-PGM HOR electrocatalysts. Fundamental understandings of the HOR mechanism are firstly reviewed, where theoretical interpretations on the low HOR kinetics in alkaline media, including the hydrogen binding energy theory, the bifunctional mechanism, and the water molecule reorganization, are particularly discussed. Subsequently, progresses of typ
Electrocatalysts
Fuel-cells
Hydrogen-oxidation-reaction
On-platinum-group-metals
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