Oxygen Reduction Reaction Durability Research Articles

In situ, fast constructing interface/doping-engineered NiCo bimetal-based composites boosting electrocatalytic oxygen reduction for zinc-air battery

Investigating cost-effective, high-performance, stable and durable oxygen reduction reaction (ORR) catalysts is imperative, yet it’s still a formidable obstacle in the advancement of metal-air batteries. In this research, NiCo-bimetallic oxides in situ combined with NiCo-bimetal alloy upon the surface of carbon-based matrix (reduced graphene oxide) (NiCo/Co-NiO/rGO) were synthesized by microwave hydrothermal treatment coupled with an ultrafast Joule heating shock process. The interfacial charge transfer between the bimetal alloy and metal oxide in NiCo/Co-NiO/rGO resulted in electron redistribution at the heterointerface, where *O species migrated to the NiCo alloy surface through Mn+-O-M0 (M=Ni, Co and n=2, 3) bonds, facilitating continuous electron transport between the two phases and unveiling added active sites. Introducing abundant oxygen vacancies by Ni3+ and Co3+ facilitated charge transfer between different valence states and led to forming more active sites, thus significantly enhancing ORR performance. More importantly, solid solution strengthening within the NiCo-bimetallic alloy mitigated the oxidation and corrosion of the catalyst. Therefore, the as-synthesized NiCo/Co-NiO/rGO(5 % Co) exhibited excellent ORR performance under an alkaline medium. It achieved a half-wave potential(E1/2) of 0.85 V(vs. RHE) and maintained 89.10 % of its current density after a 12-h long-term reaction. The assembled zinc-air battery (ZAB) employing this catalyst proved remarkable specific capacity (807.04 mAh·gZn−1), power density (95.54 mW cm−2) and cycling stability (over 240 h), outperforming that of commercial Pt/C+RuO2-based ZAB device. This study presents a viable approach for fabricating low-cost dual transition metal-based catalysts, thereby boosting their electrocatalytic performance and enhancing the efficiency and longevity of metal-air batteries.

Electron Donor–Acceptor Activated Single Atomic Sites for Boosting Oxygen Reduction Reaction

AbstractFabricating efficient non‐platinum‐group‐metal catalysts for the oxygen reduction reaction (ORR) in proton‐exchange membrane fuel cells still remains a big challenge. This study creates a unique bamboo‐like architecture of Mn and Fe single atomic sites (SASs) anchored on core‐shell structure of nanopaticles@carbon nanotubes (MnFe SASs/NPs@CNTs) via a precursor route, where the Fe nanoparticles (NPs) (identified as γ‐Fe and Austenite) are confined into CNTs, such an architecture exhibits compelling ORR activity and durability in 0.1 m HClO4. Experiments and calculations both reveal that the electron donor–acceptor paradigm between Mn SASs and Fe NPs launches a lattice‐electron coupling mechanism not only increasing occupation of π‐antibonding orbital in Mn−*O intermediates but also rising Jahn–Teller effect, thereby destabilize the Mn−*O intermediate and eventually facilitate the potential‐limiting step from *O to *OH. Such a coupling activation of the ORR‐inert Mn SASs greatly improves ORR performances of MnFe SASs/NPs@CNTs.

Improvement in ORR Durability of Fe Single-Atom Carbon Catalysts Hybridized with CeO2 Nanozyme.

FeNC catalysts are considered one of the most promising alternatives to platinum group metals for the oxygen reduction reaction (ORR). Despite the extensive research on improving ORR activity, the undesirable durability of FeNC is still a critical issue for its practical application. Herein, inspired by the antioxidant mechanism of natural enzymes, CeO2 nanozymes featuring catalase-like and superoxide dismutase-like activities were coupled with FeNC to mitigate the attack of reactive oxygen species (ROS) for improving durability. Benefiting from the multienzyme-like activities of CeO2, ROS generated from FeNC is instantaneously eliminated to alleviate the corrosion of carbon and demetallization of metal sites. Consequently, FeNC/CeO2 exhibits better ORR durability with a decay of only 5 mV compared to FeNC (18 mV) in neutral electrolyte after 10k cycles. The FeNC/CeO2-based zinc-air battery also shows minimal voltage decay over 140 h in galvanostatic discharge-charge cycling tests, outperforming FeNC and commercial Pt/C.

Graphene benefits penta-nitrogen coordinated iron and catalytic stability of oxygen reduction reaction

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 (E1/2 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 H2-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.

Improving the durability and anti-poisoning properties of platinum catalysts by carbon shell encapsulation: A promising approach for both cathode and anode catalysts for polymer electrolyte membrane fuel cells

Carbon shell encapsulation has emerged as an effective strategy for enhancing the durability of Pt-based electrocatalysts for polymer electrolyte membrane fuel cells (PEFCs). Here, a nitrogen-doped carbon shell-encapsulated Pt catalyst supported on Ketjen black (Pt@C/KB) was synthesized, and its catalytic performance was characterized. The oxygen reduction reaction (ORR) performance and anti-poisoning properties were investigated in 0.1 M HClO4 with and without H2SO4 or H3PO4 poisoning, using a rotating ring-disk electrode (RRDE) technique. Despite a decrease in the electrochemical surface area (ECSA), Pt@C/KB encapsulated by a thin graphene-like carbon shell (<1 nm thick) showed high selectivity for the four-electron reaction due to its superior anti-poisoning properties, as well as improved ORR activity and durability. The H2O2 yield of Pt@C/KB, the precursor of hydroxyl radicals, was decreased approximately one third compared to bare Pt catalyst and the gap was more pronounced in the low potential (E ≤ 0.1 V/RHE) where close to practical anode potential, suggesting that Pt@C/KB can be applied as a new anode catalyst. Applying carbon core-shell catalysts to both the cathode and anode is a prospectively effective approach for improving the cell performance by improving the ORR activity and anti-poisoning properties, as well as for extending the lifespan of PEFCs.

2D Co-N-C catalysts derived by 1D CoxZn1-xO hexagonal microrods for oxygen reduction reaction

A novel and feasible strategy to construct 2D Co-N-C catalyst from one-dimensional (1D) CoxZn1-xO microrod is reported. In the strategy, 1D CoxZn1-xO microrods are firstly transformed into CoxZn1-xO@CoZn-ZIF hexagonal core-shell microrods by regulating the reaction conditions of high-pressure vapor-solid transformation, and subsequently pyrolyzed at high temperature to form Co-N-C hexagonal microtubes, which are finally fractured along its edges under the action of thermal stress, evolving gradually to Co-N-C nanosheets. Besides, by investigating the effects of Co doping contents, a catalyst with optimal chemical and structural properties and more highly accessible Co-N4 active sites has achieved respectable activity and stability for the oxygen reduction reaction (ORR) in alkaline media. Among them, Co0.3-N-C NS exhibits superior ORR performance (Eon=1.01 V, E1/2 = 0.87 V), durability and tolerance to methanol than those of commercial Pt/C catalysts (Eon=0.99 V, E1/2 = 0.85 V) in alkaline media.

Carbon‐Embedded Pt Alloy Cluster Catalysts for Proton Exchange Membrane Fuel Cells

AbstractMinimizing the use of platinum (Pt) in proton exchange membrane fuel cells (PEMFCs) is crucial for expanding the PEMFC market. The most straightforward approach would be to reduce the size of Pt particles. However, small Pt clusters, particularly those &lt;2 nm in size, typically exhibit reduced activity for the oxygen reduction reaction (ORR) due to the overly strong adsorption of oxygen intermediates. Additionally, these small Pt clusters tend to degrade more quickly, resulting in lower durability. In this study, carbon‐embedded Pt alloy cluster catalysts (PtFe, PtCo, PtNi) that demonstrate high activity and durability in the PEMFC cathode are presented. Density functional theory calculations indicate that carbon atoms stably adsorb onto the Fe sites of PtFe clusters, making the neighboring Pt sites active for ORR with an optimal adsorption strength for oxygen intermediates. This research can pave the way for developing durable and efficient ORR catalysts while significantly reducing Pt usage in PEMFCs.

Strong Interaction between Titanium Carbonitride Embedded in Mesoporous Carbon Nanofibers and Pt Enables Durable Oxygen Reduction.

Platinum (Pt) supported on high surface area carbon has been the most widely used electrocatalyst in proton exchange membrane fuel cell (PEMFC). However, conventional carbon supports are susceptible to corrosion at high potentials, leading to severe degradation of electrochemical performance. In this work, titanium carbonitride embedded in mesoporous carbon nanofibers (m-TiCN NFs) are reported as a promising alternative to address this issue. Benefiting from the interpenetrating conductive pathways inside the one-dimensional (1D) nanostructures and the embedded TiCN nanoparticles (NPs), m-TiCN NFs exhibit excellent stability at high potentials and interact strongly with Pt NPs. Subsequently, m-TiCN NFs-supported Pt NPs deliver remarkably enhanced oxygen reduction reaction (ORR) activity and durability, with negligible activity decay and less than 5% loss of electrochemical surface area（ECSA） after 50000 cycles. Moreover, the fuel cell assembled by this catalyst delivers a maximum power density of 1.22W cm-2 and merely 3% loss after 30000 cycles of accelerated durability tests under U.S. Department of Energy (DOE) protocols. The improved ORR activity and durability are attributed to the superior corrosion resistance of the m-TiCN NF support and the strong interaction between Pt and m-TiCN NFs.

Atomic controlled shell thickness on Pt@Pt3Ti core-shell nanoparticles for efficient and durable oxygen reduction

The exploitation of durable and highly active Pt-based electrocatalysts for the oxygen reduction reaction (ORR) is essential for the commercialization of proton exchange membrane fuel cells (PEMFCs). Herein, we designed Pt@Pt3Ti core-shell nanoparticles with atomic-controllable shells through precise thermal diffusing Ti into Pt nanoparticles for effective and durable ORR. Combining theoretical and experiment analysis, we found that the lattice strain of Pt3Ti shells can be tailored by precisely controlling the thickness of Pt3Ti shell in atomic-scale on account of the lattice constant difference between Pt and Pt3Ti to optimize adsorption properties of Pt3Ti for ORR intermediates, thus enhancing its performance. The Pt@Pt3Ti catalyst with one-atomic Pt3Ti shell (Pt@1L-Pt3Ti/TiO2-C) demonstrates excellent performance with mass activity of 592 mA mgPt−1 and durability nearly 19.5-fold that of commercial Pt/C with negligible decay (2 %) after 30,000 potential cycles (0.6–1.0 V vs. RHE). Notably, at higher potential cycles (1.0 V-1.5 V vs. RHE), Pt@1L-Pt3Ti/TiO2-C also showed far superior durability than Pt/C (9.6 % decayed while 54.8 % for commercial Pt/C). This excellent stability is derived from the intrinsic stability of Pt3Ti alloy and the confinement effect of TiO2-C. The catalyst’s enhancement was further confirmed in PEMFC configuration.

Boosting oxygen reduction durability by embedding Co9S8 nanoparticles into Co single atoms anchored porous carbon frameworks

Developing an efficient and low-cost oxygen reduction electrocatalyst is essential for the application of aqueous zinc-air batteries (ZABs). Herein, we report a facile adsorption-confined pyrolysis strategy to fabricate the hybrid electrocatalyst (denoted as Co9S8/CoSA-PC) by embedding Co9S8 nanoparticles into Co single atoms (Co-SAs) anchored porous carbon sheets for boosting oxygen reduction reaction (ORR) durability. In this strategy, the Co2+ ions are first absorbed into oxygen-rich porous carbon nanosheets and further form the Co-SAs with the help of thiourea in the following pyrolysis procedure, which is believed to be able to confine the generated Co9S8 nanoparticles into carbon frameworks due to their interface interaction. Benefiting from the synergistic effect of different components, the obtained Co9S8/CoSA-PC electrocatalyst for ORR exhibits outstanding catalytic activity with a half-wave potential of 0.82 V and a distinguished long-term durability with a current retention of 80 % after cycling 80 h under alkaline conditions, which is superior to commercial Pt/C. Moreover, the assembled ZABs with Co9S8/CoSA-PC as cathodic catalyst deliver a high specific capacity of 764 mAh gZn−1 at 10 mA cm−2 and the outstanding peak power density of up to 221.4 mW cm−2. This work provides a novel structure design strategy to prepare transition metal sulfide-based electrocatalysts with superior durability for ORR.

Ag@Co/Zn N‐Doped Carbon as Antibacterial Oxygen Reduction Catalysts for Microbial Fuel Cells

Biofouling of air cathode surface decreases the electricity generation performance of membrane‐free microbial fuel cells (MFCs). Ag@Co/Zn N‐doped carbon (Ag@Co/Zn‐NC) is designed as an antibacterial oxygen reduction reaction (ORR) catalyst to inhibit biofouling on the cathode surface. The Co/Zn‐NC active component promotes ORR catalytic activity through the advantages of well‐distributed Co nanoparticles and numerous active sites. Superficial Ag nanoparticles act as antibacterial active species to inhibit bacterial proliferation and suppress biofilm growth. Ag@Co/Zn‐NC catalyst prevents bacterial adhesion and biofilm formation, effectively preventing excessive biofouling on the cathode surface. The antibacterial catalyst maintains a high catalytic activity and good ion diffusion properties without the adverse effects of biofouling, resulting in enhanced ORR durability of the air cathode. The assembled MFCs achieve high electricity generation during long‐term cyclic operation. The maximum power density retention percentage (82.6%) is higher than that of Co/Zn‐NC MFC (65.3%) and Pt/C MFC (52.4%) after continuous operation for 1200 h. Excellent operational durability is revealed for the air‐cathode MFCs assembled with the antibacterial ORR catalyst during the cyclic process. The novelty of this study is that the design of antibacterial catalysts inhibits the excessive growth of the cathode biofilm to improve the cyclic electricity generation performance of MFCs.

Effective Promotion of the Activity and Stability of Cathodes for Protonic Ceramic Fuel Cells

AbstractProtonic ceramic fuel cells (PCFCs) are emerging as effective devices for their excellent capability of converting energy. However, the sluggish oxygen reduction reaction (ORR) and poor durability of cathodes greatly limit their widespread commercialization. Herein, a multi‐cationic oxide nano‐catalyst with a nominal composition of Pr0.2Ce0.2Ni0.2Co0.2Fe0.2Ox (denoted as PCNCFO) is designed and reported, which significantly enhanced the ORR activity and durability of a typical PrBaCo2O5+δ (PBC) cathode. The PCNCFO‐coated PBC cathode delivered impressive cell performance with a small polarization resistance of only 0.18 Ω cm2 at 600 °C on symmetrical cells and a high peak power density (PPD) of 1.31 W cm−2 at 650 °C on single cells. Meanwhile, the PCNCFO‐coated PBC cathode exhibits excellent operational stability both on symmetrical and single cells. It is indicated that the Ce oxide in the nano‐catalyst coating can react with the segregated Ba to form active species, while others can activate the surface of the cathode, as indicated by the transmission electron microscope (TEM) and distribution of relaxation time (DRT) analyses.

Multiscale Regulation of Ordered PtCu Intermetallic Electrocatalyst for Highly Durable Oxygen Reduction Reaction.

Transforming the Pt-M alloy into an ordered intermetallic is an effective strategy to improve the electrocatalytic activity and stability toward the oxygen reduction reaction (ORR). However, the synthesis of nanosized intermetallics remains challenging. Herein, we report an efficient ORR electrocatalyst, consisting of a monodisperse nanosized PtCu intermetallic on hollow mesoporous carbon spheres (HMCS). As predicted by theoretical calculations, PtCu intermetallics exhibit beneficial electronic structure, with a low theoretical overpotential of 0.33 V and enhanced Cu stability. Resulting from the multiscale modulation of catalyst structure, the O-PtCu/HMCS catalyst delivers a high mass activity of 2.73 A cm-2Pt at 0.9 V and remarkable stability. Identical location transmission electron microscopy (IL-TEM) investigations demonstrate that the rate of carbon corrosion is alleviated on HMCS, which contributes to the long-term durability. This work provides a promising design strategy for an ORR electrocatalyst, and the IL-TEM investigations offer new perspectives for the performance enhancement mechanism.

Regulating the Electronic Synergy of Asymmetric Atomic Fe Sites with Adjacent Defects for Boosting Activity and Durability toward Oxygen Reduction

AbstractThe oxygen reduction reaction (ORR) plays a fundamental role in sustainable energy technologies. However, the creation of non‐precious metal electrocatalysts with high ORR activity and durability under all pH conditions is of great significance but remains challenging. Herein, the aim is to overcome this challenge by creating a Fe single atom catalyst on a 2D defect‐containing nitrogen‐doped carbon support (Fe1/DNC) via a microenvironment engineering strategy. Microkinetic modeling reveals that FeN4(OH) moieties are the real active sites under reaction conditions. Due to the synergistic promotion effect of denser accessible FeN4(OH) moieties and defect‐induced electronic properties, Fe1/DNC catalyst achieves extraordinary ORR activity under alkaline, acidic, and neutral conditions, with half‐wave potentials of 0.95, 0.82, and 0.70 V, respectively. Moreover, a negligible performance decay is observed with this Fe catalyst in stability and methanol tolerance tests. Zn‐air battery employing Fe1/DNC delivers remarkable peak power density and long‐term operational durability. Theoretical analysis provides compelling evidence that the defects adjacent to FeN4(OH) moieties can endow an inductive effect to reshape electronic properties to balance the OOH* formation and OH* reduction. This work offers insight into the regulation of asymmetric coordination structure and electronic properties of metal sites for boosting electrocatalytic activity and stability.

Pd@CoFe Alloys on N-Doped Carbon Derived from Charred Tissue Paper as Synergistic Bifunctional Oxygen Electrocatalysts

Integrating more active components into a catalyst material could facilitate the development of multifunctional electrocatalysts for energy conversion and storage applications. In this study, we developed a multifunctional electrocatalyst, namely, Pd alloyed with Co-Fe deposited on N-doped mesoporous carbon derived from tissue paper (Pd@Co-Fe/N-TDC). The synergism in Pd@Co-Fe/N-TDC, stemming from the interatomic alloy between Pd and Co-Fe, N-doped mesoporous carbon with defective surfaces, distribution of polyhedral Pd nanoparticles, and strong metal-support interfacial interaction, resulted in significantly high electrocatalytic performance for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Pd@Co-Fe/N-TDC was found to be an efficient bifunctional oxygen electrocatalyst, and this was evidenced by a high onset potential (1.01 V) and kinetic current density (2.6 mA/cm2) for the ORR and by a low overpotential (296 mV) and a low Tafel slope value (38 mV/dec) for the OER, along with a small ΔE of 736 mV. The catalyst also exhibited high durability for both ORR and OER, even after 10000 and 5000 cycles, respectively. Theoretical assessment provides an insight into the synergism of active metal sites in Pd@Co-Fe/N-TDC, which showed its potential for use as a non-Pt electrocatalyst for energy applications.

Pt-Fe alloy supported on Fe/NC catalyst with high activity and durability for oxygen reduction reaction

In this paper, Pt-Fe alloy with low-content of Pt (2 %) was distributed uniformly over the porous Fe/NC substrate treated by nitric acid etching, with small amount of metallic Fe and Pt nanoparticles. The optimized Pt-Fe alloy on Fe/NC substrate showed higher ORR performance with the E1/2 of around 0.83 V vs. RHE as well as faster catalytic kinetics. In addition, the catalytic activity has not been decayed through an accelerated durability test after 5000 cycles CVs, indicating better catalytic stability for the alloying catalyst. The introduction of Pt elements into Fe/NC substrate increased the numbers and species of ORR active sites, invoking higher ORR activity comparing with isolated Fe/NC catalyst. The acid etching provided more defects for the substrate to anchor the active sites stably. Moreover, the synergistic effect originated from the alloying of Pt and Fe modulated the electronic structure of Pt, increasing the ORR activity with low yield of H2O2. This decreasing H2O2 yield can weaken the Fenton reaction to prevent the dissolution of Fe in the acid solution, which can improve the stability of the catalysts to meet the commercial needs for PEMFC.

High entropy La(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 with tailored eg occupancy and transition metal-oxygen bond properties for oxygen reduction reaction

Forming high entropy oxide provides a feasible approach to finding a balance among moderate eg occupancy, high transition metal-oxygen (TM-O) covalency, and lattice energy, which is essential to ensure efficient and durable oxygen reduction reaction (ORR) process for perovskite lanthanide-transition metal oxides (LaTMO3). However, due to the compositional complexity, clarifying the relevance among the high entropy components, eg occupancy, TM-O properties, and ORR performance still remains a challenge. Herein, adopting the B site entropy-driven strategy, a series of LaTMO3 (TM = Cr, Mn, Fe, Co, Ni) with tunable eg occupancy and TM-O bond properties are synthesized, and the correlations between high entropy elements, eg occupancy, TM-O properties, and ORR performances are revealed quantitively based on the crystal field theory and the Phillips–Van Vechten–Levine (P–V–L) valence bond theory. High entropy La(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 delivers a low overpotential of 493 mV (vs. 503 mV for LaMnO3) and a minuscule decline by only 1.7% (vs. 4.4% for LaMnO3) in half wave potential after 10,000 cycles, which can be associated with the tailored eg occupancy (1.06) and the significant enhancement in both TM-O covalency (4%) and lattice energy (691.75 kJ mol–1). This work not only demonstrates the prospects of high entropy LaTMO3 in the ORR field but also provides a new perspective for the quantitative analysis of the structure-activity relationship for high entropy oxide ORR catalysts.

Morphology engineering of self-assembled bimetallic PtCo alloy nanofoams as efficient multifunctional electrocatalysts for oxygen reduction and alcohol oxidation

The exploration of high properties of electrocatalysts is imperative for the commercialization application of fuel cells. Enhancing the catalytic activity and stability of Pt-based catalysts can be achieved by rationally designing their morphology and composition. Here, we synthesized self-assembled PtCo alloy nanofoams (ANs) catalysts with controllable surface composition and porous network. The experimental results show that prepared PtxCo1-ANs catalysts display excellent electrochemical performance in oxygen reduction reaction (ORR), methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). Interestingly, the mass activities of Pt2Co1-ANs with optimized surface composition for ORR, MOR, and EOR are 6.41, 6.64, and 7.71-fold higher than commercial Pt/C catalysts, respectively. Meantime, it also maintains high electrocatalytic durability in ORR, MOR, and EOR. Such results ascribe to the modified surface composition, optimized electronic structure, and porous interconnected nanofoam structure. These findings provide valuable insights into the design of highly active and durable multifunctional electrocatalysts with controllable shapes and composition.

Multiple Metal-Nitrogen Bonds Synergistically Boosting the Activity and Durability of High-Entropy Alloy Electrocatalysts.

The development of Pt-based catalysts for use in fuel cells that meet performance targets of high activity, maximized stability, and low cost remains a huge challenge. Herein, we report a nitrogen (N)-doped high-entropy alloy (HEA) electrocatalyst that consists of a Pt-rich shell and a N-doped PtCoFeNiCu core on a carbon support (denoted as N-Pt/HEA/C). The N-Pt/HEA/C catalyst showed a high mass activity of 1.34 A mgPt-1 at 0.9 V for the oxygen reduction reaction (ORR) in rotating disk electrode (RDE) testing, which substantially outperformed commercial Pt/C and most of the other binary/ternary Pt-based catalysts. The N-Pt/HEA/C catalyst also demonstrated excellent stability in both RDE and membrane electrode assembly (MEA) testing. Using operando X-ray absorption spectroscopy (XAS) measurements and theoretical calculations, we revealed that the enhanced ORR activity of N-Pt/HEA/C originated from the optimized adsorption energy of intermediates, resulting in the tailored electronic structure formed upon N-doping. Furthermore, we showed that the multiple metal-nitrogen bonds formed synergistically improved the corrosion resistance of the 3d transition metals and enhanced the ORR durability.

Ultradurable Pt-Based Catalysts for Oxygen Reduction Electrocatalysis

An oxygen reduction reaction (ORR) is the key half reaction of proton exchange membrane fuel cells (PEMFCs), and is highly dependent on Pt-based nanocrystals as core electrocatalysts. Despite the exceptional ORR activity from adjusting the electronic structures of surface or near-surface atoms, several serious issues, including the corrosion of carbon supports, the preferential leaching of active metal elements, the instability of surface low-coordinated atoms and the sintering/agglomeration of nanocrystals, still exist, challenging the ORR durability of developed Pt-based ORR catalysts. From the point of view of the catalyst structure design, in this review, we summarized the state-of-the-art structural regulation strategies for improving the ORR durability of Pt-based catalysts. The current limitation of Pt-based binary catalysts for ORR electrocatalysis is firstly discussed, and the detailed strategies are further classified into the optimization of supports, metal-doped alloys, core/shell structures, intermetallics and high-entropy alloys, etc. The structure–performance relationship is detailedly explained, especially emphasizing the elimination of the above restrictions. Finally, the existing challenges and future research direction are further presented, aiming at practicing the PEMFC devices of the ultradurable Pt-based catalysts.