The integration of Fe dopant and interfacial FeOOH into Ni-MOFs [Fe-doped-(Ni-MOFs)/FeOOH] to construct FeÀ OÀ NiÀ OÀ Fe bonding is demonstrated and the origin of remarkable electrocatalytic performance of Ni-MOFs is elucidated. X-ray absorption/photoelectron spectroscopy and theoretical calculation results indicate that Fe-OÀ NiÀ OÀ Fe bonding can facilitate the distorted coordinated structure of the Ni site with a short nickel-oxygen bond and low coordination number, and can promote the redistribution of Ni/Fe charge density to efficiently regulate the adsorption behavior of key intermediates with a near-optimal d-band center.Here the Fe-doped-(Ni-MOFs)/FeOOH with interfacial FeÀ OÀ NiÀ OÀ Fe bonding shows superior catalytic performance for OER with a low overpotential of 210 mV at 15 mA cm À 2 and excellent stability with � 3 % attenuation after a 120 h cycle test. This study provides a novel strategy to design high-performance Ni/Fe-based electrocatalysts for OER in alkaline media.

A class of core-shell low-platinum catalyst, with well-dispersed inexpensive titanium copper nitride nanoparticles as cores and atomic platinum layers as shells exhibiting high activity and stability for the oxygen reduction reaction (ORR) is successfully developed. Using nitrided carbon nanotubes (NCNTs) as the support greatly improved the morphology and dispersion of the nitride nanoparticles, resulting in significant enhancement of the catalyst's performance. The optimized catalyst, Ti0.9Cu0.1N@Pt/NCNTs, has a Pt mass activity five times higher than that of commercial Pt/C, comparable to that of core-shell catalysts with precious metal nanoparticles as the core and much higher than the latter if we take into account the mass activity of all platinum-group metals. Furthermore, only a minimal loss of activity is observable after 10,000 potential cycles, demonstrating the catalyst's high stability. Atomic-scale elemental mapping confirmed that the core-shell structure of the catalyst remained intact after durability testing. The approach may open a pathway to design and prepare high performance inexpensive core-shell catalysts for a wide range of applications in energy-conversion processes.

Proton exchange membrane fuel cells (PEMFCs) are a highly efficient hydrogen energy conversion technology, which shows great potential in mitigating carbon emissions and the energy crisis. Currently, to accelerate the kinetics of the oxygen reduction reaction (ORR) required for PEMFCs, extensive utilization of expensive and rare platinum‐based catalysts are required at the cathodic side, impeding their large‐scale commercialization. In response to this issue, atomically dispersed metal–nitrogen–carbon (M–N–C) catalysts with cost‐effectiveness, encouraging activity, and unique advantages (e.g., homogeneous activity sites, high atom efficiency, and intrinsic activity) have been widely investigated. Considerable progress in this domain has been witnessed in the past decade. Herein, a comprehensive summary of recent development in atomically dispersed M–N–C catalysts for the ORR under acidic conditions and of their application in the membrane electrode assembly (MEA) of PEM fuel cells, are presented. The ORR mechanisms, composition, and operating principles of PEMFCs are introduced. Thereafter, atomically dispersed M–N–C catalysts towards improved acidic ORR and MEA performance is summarized in detail, and improvement strategies for MEA performance and stability are systematically analyzed. Finally, remaining challenges and significant research directions for design and development of high‐performance atomically dispersed M–N–C catalysts and MEA are discussed.

An effective strategy was demonstrated to develop a highly durable catalyst prototype that combines superfine Pt-based intermetallic nanoparticles with mesoporous carbon.