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Graphene supported FeN5 active sites, exhibiting high activity and stability of oxygen reduction reaction, enable a H2-air fuel cell to decay little during the latter 20–100 h operation. [Display omitted] • Electrochemically-exfoliated graphene improves forming FeN 5 with NH 3. • Graphene benefits catalytic stability of oxygen reduction reaction. • Fuel cell keep stable with little decay in latter 80 h operation. • High half-wave potentials in alkaline medium (0.940 V). Metal-nitrogen-carbon catalytic material, generally thought as a promising low-cost electrocatalyst of oxygen reduction reaction (ORR), surfers from long-term catalytic durability for fuel cell and metal-air battery. Here, we describe an approach of synthesizing electrochemically exfoliated graphene supported penta-nitrogen coordinated iron exhibiting encouraging ORR catalytic activity and durability. The synthesized catalyst exhibits high half-wave potentials in alkaline medium (E 1/2 0.940 V) enabling high-performance zinc-air battery and in acidic condition for durable fuel cell with a high peak power density (630 mW cm−2). The current density of a proton exchange membrane fuel cell loading the catalyst as cathode tends to decay little after initial hours under H 2 -air measurement, remarkably inhibiting commonly decline tendency of iron–nitrogen-carbon catalysts. DFT calculation combined with extensive experimental investigations demonstrate that penta-nitrogen coordinated iron supported by graphene is thermodynamically stable, and thus benefits the catalytic stability of ORR. [ABSTRACT FROM AUTHOR]

Designing efficient and stable single-atom catalysts (SACs) for the oxygen reduction reaction (ORR) is essential to promote fuel cell commercialization. In this study, the Bayesian Regularization Neural Network (BRNN) has been used to determine the carbothermal shock (CTS) conditions for preparing high-loading Pt-Fe/C SACs. The BRNN model effectively identified a low reaction temperature of 283 °C for achieving high-loading (15 wt %) Pt-Fe/C SACs. Based on this model, we successfully synthesized Pt-Fe/C SACs with a metal mass content of 11.31 wt % using the CTS method. These ultrahigh content metal Pt-Fe/C SACs consisted of dispersed single atoms and foam-like atomic constructions, namely Pt-Fe/C atom foam catalysts (AFCs), rendered them promising candidates for electrocatalysis applications. The Pt-Fe/C AFCs exhibited good catalytic activity and durability toward ORR in alkaline conditions. The Pt-Fe/C AFCs were employed in a direct borohydride fuel cell (DBFC) as cathode catalyst, which resulted in a maximum power density of 214 mW cm−2 at 60 °C and demonstrated stable discharge for 40 h at room temperature. The electrocatalytic performance of the Pt-Fe/C AFCs surpassed that of low-loading Pt-Fe/C SACs and commercial Pt/C catalysts. The rapid ramp-up rate and the rapid cooling rate of the CTS process enabled the incorporation of high-loading Pt and Fe metal atoms into the graphitized carbon layer, resulting in an increased number of active sites of the Pt-Fe/C AFCs. This work provides an effective strategy for manufacturing efficient and stable SACs for practical applications in fuel cells. [Display omitted] • The Bayesian Regularization Neural Network is used to determine the CTS conditions. • Pt-Fe/C AFCs with metal content of 11.31 wt % is successfully synthesize by the CTS method. • The Pt-Fe/C AFCs exhibit good catalytic activity and durability towards ORR. • The DBFC using Pt-Fe/C AFCs cathode achieves a maximum power density of 214 mW cm−2. [ABSTRACT FROM AUTHOR]

Atomically dispersed transition metal‐Nx sites have emerged as a frontier for electrocatalysis because of the maximized atom utilization. However, there is still the problem that the reactant is difficult to reach active sites inside the catalytic layer in the practical proton exchange membrane fuel cell (PEMFC) testing, resulting in the ineffective utilization of the deeply hided active sites. In the device manner, the favorite structure of electrocatalysts for good mass transfer is vital for PEMFC. Herein, a facile one‐step approach to synthesize atomically dispersed Fe‐Nx species on hierarchically porous carbon nanostructures as a high‐efficient and stable atomically dispersed catalyst for oxygen reduction in acidic media is reported, which is achieved by a predesigned hierarchical covalent organic polymer (COP) with iron anchored. COP materials with well‐defined building blocks can stabilize the dopants and provide efficient mass transport. The appropriate hierarchical pore structure is proved to facilitate the mass transport of reactants to the active sites, ensuring the utilization of active sites in devices. Particularly, the structurally optimized HSAC/Fe‐3 displays a maximum power density of up to 824 mW cm−2, higher than other samples with fewer mesopores. Accordingly, this work will offer inspirations for designing efficient atomically dispersed electrocatalyst in PEMFC device. [ABSTRACT FROM AUTHOR]

The serious durability concerns of carbon supported Pt electrocatalysts for oxygen reduction reaction (ORR) have strictly limited the commercialization of fuel cells. Herein, cable-like carbon nanotubes (CNTs)@SnO 2 core@shell supports with regulable electronic metal-support interaction (EMSI) are designed for Pt nanoparticles (NPs) as ORR catalysts. Impressively, the best-performing Pt-CNT@SnO 2 catalyst with optimized d- band center achieves an excellent activity (mass activity (MA) of 0.68 A mg Pt −1 at 0.9 V iR-free and peak power density of 1618 mW cm−2) and record-high durability in H 2 -O 2 fuel cells (9.2 % MA and 8 % power density loss after 5k cycles under 1.0–1.5 V) among the reported Pt-based catalysts, which is also superior to the U.S. DOE 2025 targets. Density functional theory (DFT) calculations reveal that the strong metal-support bonding interaction (SMSBI) endows much larger adhesion energy and migration barrier towards Pt atoms compared to carbon supports, leading to the extraordinarily high stability in fuel cells. [Display omitted] • The Pt-CNT@SnO 2 catalyst demonstrates the best stability among reported Pt-based ORR catalysts under high potential regions. • Strong metal-support bonding interaction (SMSBI) between Pt and SnO 2 is able to stabilize Pt NPs against migration/agglomeration. • The d -band center of Pt is optimized by regulating the electronic metal-support interaction (EMSI). [ABSTRACT FROM AUTHOR]