Driven by the persisting poor understanding of the sluggish kinetics of the hydrogen evolution reaction (HER) on Pt in alkaline media, a direct correlation of the interfacial water structure and activity is still yet to be established. Herein, using Pt and Pt–Ni nanoparticles we first demonstrate a strong dependence of the proton donor structure on the HER activity and pH. The structure of the first layer changes from the proton acceptors to the donors with increasing pH. In the base, the reactivity of the interfacial water varied its structure, and the activation energies of water dissociation increased in the sequence: the dangling O−H bonds < the trihedrally coordinated water < the tetrahedrally coordinated water. Moreover, optimizing the adsorption of H and OH intermediates can re‐orientate the interfacial water molecules with their H atoms pointing towards the electrode surface, thereby enhancing the kinetics of HER. Our results clarified the dynamic role of the water structure at the electrode–electrolyte interface during HER and the design of highly efficient HER catalysts.

Co single-atom (CoSA) catalysts of the CoN4 moiety usually show an unsatisfactory oxygen reduction reaction (ORR) activity due to poor O2 activation. Herein, we open up a novel strategy to...

An Fe/N/C catalyst derived from the pyrolysis of metal–organic frameworks, for example, a zeolitic‐imidazolate‐framework‐8 (ZIF‐8), has been regarded as one of the most promising non‐precious metal catalysts toward oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). However, its ORR mass activity is still much inferior to that of Pt, partly because of the lack of general and efficient synthetic strategies. Herein, a general carboxylate‐assisted strategy that dramatically enhances the ORR mass activity of ZIF‐derived Fe/N/C catalysts is reported. The carboxylate is found to promote the formation of Fe/N/C catalysts with denser accessible active sites and entangled carbon nanotubes, as well as a higher mesoporosity. These structural advantages make the carboxylate‐assisted Fe/N/C catalysts show a 2–10 fold higher ORR mass activity than the common carboxylate‐free one in various cases. When applied in H2–O2 PEMFCs, the active acetate‐assisted Fe/N/C catalyst generates a peak power density of 1.33 W cm−2, a new record of peak power density for a H2–O2 PEMFC with non‐Pt ORR catalysts.

Metal-containing nanoparticles (M-NPs) in metal/ nitrogen-doped carbon (M-N-C) catalysts have been considered hostile to the acidic oxygen reduction reaction (ORR). The relation between M-NPs and the active sites of metal coordinated with nitrogen (MN x) is hard to establish in acid medium owing to the poor stability of M-NPs. Herein, we develop a strategy to successfully construct a new FeCo-N-C catalyst containing highly active M-NPs and MN 4 composite sites (M/FeCo-SAs-N-C). Enhanced catalytic activity and stability of M/FeCo-SAs-N-C is shown experimentally. Calculations reveal that there is a strong interaction between M-NPs and FeN 4 sites, which can favor ORR by activating the O À O bond, thus facilitating a direct 4 e À process. Those findings firstly shed light on the highly active M-NPs and FeN 4 composite sites for catalyzing acid oxygen reduction reaction, and the relevant reaction mechanism is suggested.