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The limited durability of metal-nitrogen-carbon electrocatalysts severely restricts their applicability for the oxygen reduction reaction in proton exchange membrane fuel cells. In this study, we employ the chemical vapor modification method to alter the configuration of active sites from FeN4 to the stable monosymmetric FeN2+N'2, along with enhancing the degree of graphitization in the carbon substrate. This improvement effectively addresses the challenges associated with Fe active center leaching caused by N-group protonation and free radicals attack due to the 2-electron oxygen reduction reaction. The electrocatalyst with neoteric active site exhibited excellent durability. During accelerated aging test, the electrocatalyst exhibited negligible decline in its half-wave potential even after undergoing 200,000 potential cycles. Furthermore, when subjected to operational conditions representative of fuel cell systems, the electrocatalyst displayed remarkable durability, sustaining stable performance for a duration exceeding 248 h. The significant improvement in durability provides highly valuable insights for the practical application of metal-nitrogen-carbon electrocatalysts. The limited durability of metal-nitrogen-carbon electrocatalysts hinders their use in proton exchange membrane fuel cells for the oxygen reduction reaction. Here the authors transform active sites from FeN4 to stable monosymmetric FeN2 + N'2 via chemical vapor modification, resulting in enhanced improving the durability of the catalyst. [ABSTRACT FROM AUTHOR]

Alleviating the degradation issue of Pt based alloy catalysts, thereby simultaneously achieving high mass activity and high durability in proton exchange membrane fuel cells (PEMFCs), is highly challenging. Herein, we provide a new paradigm to address this issue via delaying the place exchange between adsorbed oxygen species and surface Pt atoms, thereby inhibiting Pt dissolution, through introducing rare earth bonded subsurface oxygen atoms. We have succeeded in introducing Gd−O dipoles into Pt3Ni via a high temperature entropy‐driven process, with direct spectral evidence attained from both soft and hard X‐ray absorption spectroscopies. The higher rated power of 0.93 W cm−2 and superior current density of 562.2 mA cm−2 at 0.8 V than DOE target for heavy‐duty vehicles in H2‐air mode suggest the great potential of Gd−O−Pt3Ni towards practical application in heavy‐duty transportation. Moreover, the mass activity retention (1.04 A mgPt−1) after 40 k cycles accelerated durability tests is even 2.4 times of the initial mass activity goal for DOE 2025 (0.44 A mgPt−1), due to the weakened Pt−Oads bond interaction and the delayed place exchange process, via repulsive forces between surface O atoms and those in the sublayer. This work addresses the critical roadblocks to the widespread adoption of PEMFCs. [ABSTRACT FROM AUTHOR]

Oxygen reduction reactions (ORRs) involve a multistep proton-coupled electron process accompanied by the conversion of the apodictic spin configuration. Understanding the role of spin configurations of metals in the adsorption and desorption of oxygen intermediates during ORRs is critical for the design of efficient ORR catalysts. Herein, a platinum–rare-earth-metal-based alloy catalyst, Pt2Gd, is introduced to reveal the role of spin configurations in the catalytic activity of materials. The catalyst exhibits a unique intrinsic spin reconfiguration because of interactions between the Gd-4f and Pt-5d orbitals. The adsorption and desorption of the oxygen species are optimized by modifying the spin symmetry and electronic structures of the material for increased ORR efficiency. The Pt2Gd alloy exhibits a half-wave potential of 0.95 V and a superior mass activity of 1.5 A·mgPt−1 in a 0.1 M HClO4 electrolyte, as well as higher durability than conventional Pt/C catalysts. Theoretical calculations have proven that the spin shielding effect of Gd pairs increases the spin symmetry of Pt-5d orbitals and adsorption preferences toward spin-polarized intermediates to facilitate ORR. This work clarifies the impact of modulating the intrinsic spin state of Pt through the interaction with the local high spin 4f orbital electrons in rare-earth metals, with the aim of boosting the spin-related oxygen reduction reaction, thus fundamentally contributing to the understanding of new descriptors that control ORR activity. [ABSTRACT FROM AUTHOR]

Designing feasible electrocatalysts towards oxygen reduction reaction (ORR) requires advancement in both activity and stability, where attaining high stability is of extreme importance as the catalysts are expected to work efficiently under frequent startup/shut down circumstances for at least several thousand hours. Alloying platinum with early transition metals (i.e., Pt—La alloy) is revealed as efficient catalysts construction strategy to potentially satisfy these demands. Here we report a Pt5La intermetallic compound synthesized by a novel and facile strategy. Due to the strong electronic interactions between Pt and La, the resultant Pt5La alloy catalyst exhibits enhanced activity with half wave of 0.92 V and mass activity of 0.49 A·mgPt−1, which strictly follows the 4e transfer pathway. More importantly, the catalyst performs superior stability during 30,000 cycles of accelerated stressed test (AST) with mass activity retention of 93.9%. This study provides new opportunities for future applications of Pt-rare earth metal alloy with excellent electrocatalytic properties. [ABSTRACT FROM AUTHOR]

Catalyst/support interaction plays a vital role in catalysis towards acidic oxygen evolution (OER), and the performance reinforcement is currently interpreted by either strain or electron donation effect. We herein report that these views are insufficient, where the dynamic evolution of the interface under potential bias must be considered. Taking Nb2O5−x supported iridium (Ir/Nb2O5−x) as a model catalyst, we uncovered the dynamic migration of oxygen species between IrOx and Nb2O5−x during OER. Direct spectroscopic evidence combined with theoretical computation suggests these migrations not only regulate the in situ Ir structure towards boosted activity, but also suppress its over‐oxidation via spontaneously delivering excessive oxygen from IrOx to Nb2O5−x. The optimized Ir/Nb2O5−x thus demonstrated exceptional performance in scalable water electrolyzers, i.e. only need 1.839 V to attain 3 A cm−2 (surpassing the DOE 2025 target), and no activity decay during a 2000 h test at 2 A cm−2. [ABSTRACT FROM AUTHOR]

Designing efficient and CO‐tolerant catalysts for hydrogen oxidation reaction (HOR) in anode is one of the challenges for alkaline exchange membrane fuel cells in practical application. Herein, Ru‐MnO heterostructure with two adjacent clusters supported on commercial carbon (BP 2000) (denoted as Ru‐MnO/C) is designed to accelerate the sluggish kinetics of alkaline HOR. The cluster–cluster heterostructure interface modifies the electronic structure of Ru sites with electron transfer from Ru to MnO, then optimizes the adsorption of intermediates on Ru sites. Consequently, this catalyst exhibits high catalytic HOR activities in alkaline media with high exchange current density (3.71 mA cm−2) and mass activity (0.78 A mgRu−1). Meanwhile, the alkaline exchange membrane fuel cell delivers a specific peak power density (PPD) of 7.0 W mg−1Ru under H2/O2 condition, which is higher than that of most reported catalysts. More importantly, the catalyst also demonstrates the remarkable stability and CO‐tolerance. This work presents the superiority of cluster–cluster heterostructure interface toward efficient HOR, which is expected to further enlighten the design of advanced catalysts for electrocatalysis. [ABSTRACT FROM AUTHOR]

Developing high-performance, durable, and ultralow-loading platinum (Pt) catalysts for the oxygen reduction reaction (ORR) is crucial for advancing fuel cells. Here, a novel structured alloy catalyst is reported, characterized by Pt-Co intermetallic compounds with a Pt-skin, encapsulated by a covalent organic framework (COF) derived carbon support. This unique structure, combining alloy-induced strain effects and protective encapsulation, leads to exceptional catalytic activity and stability at an ultralow Pt loading of 0.02 mg Pt cm -2 . To be specific, this catalyst exhibits peak power densities of 1.77 W cm -2 in fuel cell tests. It demonstrates a state-of-the-art mass activity of 2.15 A mg Pt -1 (@0.9 V), which is 5.38 times that of commercial Pt/C (0.40 A mg Pt -1 ). More importantly, the fuel cell assembled with this novel catalyst displays exceptional durability, with a voltage degradation of only 9.9 mV after 100,000 cycles at 0.8 A cm -2 and a mass activity retention of 85% (1.83 A mg Pt -1 ), far exceeding the 2025 initial mass activity (MA) target (0.44 A mg Pt -1 ) of DOE by 4.2 times. Notably, the current density at 0.6 V under hydrogen-air conditions shows only a slight decline after more than 230 h., (© 2024 Wiley‐VCH GmbH.)

Catalyst/support interaction plays a vital role in catalysis towards acidic oxygen evolution (OER), and the performance reinforcement is currently interpreted by either strain or electron donation effect. We herein report that these views are insufficient, where the dynamic evolution of the interface under potential bias must be considered. Taking Nb 2 O 5-x supported iridium (Ir/Nb 2 O 5-x ) as a model catalyst, we uncovered the dynamic migration of oxygen species between IrO x and Nb 2 O 5-x during OER. Direct spectroscopic evidence combined with theoretical computation suggests these migrations not only regulate the in situ Ir structure towards boosted activity, but also suppress its over-oxidation via spontaneously delivering excessive oxygen from IrO x to Nb 2 O 5-x . The optimized Ir/Nb 2 O 5-x thus demonstrated exceptional performance in scalable water electrolyzers, i.e., only need 1.839 V to attain 3 A cm -2 (surpassing the DOE 2025 target), and no activity decay during a 2000 h test at 2 A cm -2 ., (© 2022 Wiley-VCH GmbH.)