Synthesis methods and catalytic properties of heterostructure catalysts for HER.

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Non‐metal‐based single‐atom catalysts (SACs) offer low cost, simple synthesis methods, and effective regulation for substrates. Herein, we developed a simplified pressurized gas‐assisted process, and report the first non‐metal single‐atom phosphorus with atomic‐level dispersion on unique single‐crystal Mo2C hexagonal nanosheet arrays with a (001) plane supported by carbon sheet (SAP‐Mo2C‐CS). The SAP‐Mo2C‐CS is structurally stable and shows exceptional electrocatalytic activity for the hydrogen evolution reaction (HER). A so‐called high‐active “window” based on the active sites of P atoms and their adjacent Mo atoms gives a ΔGH* close to zero for hydrogen evolution, which is the most ideal ΔGH* reported so far. Meanwhile, the moderate d‐band center value of SAP‐Mo2C‐CS can be also used as an ideal standard value to evaluate the HER performance in non‐metal‐based SACs.

Single-atom catalysts offer maximal atom utilization efficiencies and high-electronegativity heteroatoms play a crucial role in coordinating reactive single metal atoms to prevent agglomeration. However, these strong coordination bonds withdraw electron density for coordinated metal atoms and consequently affect their catalytic activity. Herein we reveal the high loading (11.3 wt%) and stabilization of moderately coordinated Cu-P3 structure on black phosphorus support by a photochemical strategy with auxiliary hydrogen. Single-atom Cu sites with an exceptional electron-rich feature show the $$\triangle {G}_{{{{{{\rm{H}}}}}}*}$$ △ G H * close to zero to favor catalysis. Neighboring Cu atoms work in synergy to lower the energy of key water adsorption and dissociation intermediates. The reported catalyst shows a low overpotential of only 41 mV at 10 mA cm−2 and Tafel slope of 53.4 mV dec−1 for the alkaline hydrogen evolution reaction, surpassing both isolated Cu single atoms and Cu nanoclusters. The promising materials design strategy sheds light on the design and fabrication of high-loading single metal atoms and the role of neighboring single atoms for enhanced reaction kinetics.

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Proton-exchange membrane fuel cells have been reported as one of the most promising substitutes for fossil fuel and limited oxygen reduction reaction (ORR) kinetics on the cathode still remain the...

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Maximizing the activity of materials towards the alkaline hydrogen evolution reaction while maintaining their structural stability under realistic working conditions remains an area of active research. Herein, we report the first controllable surface modification of graphene(G)/V8C7 heterostructures by nitrogen. Because the introduced N atoms couple electronically with V atoms, the V sites can reduce the energy barrier for water adsorption and dissociation. Investigation of the multi‐regional synergistic catalysis on N‐modified G/V8C7 by experimental observations and density‐functional‐theory calculations reveals that the increase of electron density on the epitaxial graphene enable it to become favorable for H* adsorption and the subsequent reaction with another H2O molecule. This work extends the range of surface‐engineering approaches to optimize the intrinsic properties of materials and could be generalized to the surface modification of other transition‐metal carbides.