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The current study describes a facile, time-effective and cost-viable synthesis of highly efficient Fe–N–C catalysts tailored for PEMFC. In this work, three different Fe–N–C catalysts for oxygen reduction reaction (ORR) have been synthesized by pyrolyzing different organic molecules in a microwave machine. The catalytic materials have been characterized using advanced techniques such as SEM, TEM, EDS, XPS, and BET analysis to elucidate their morphological, compositional, and surface properties. The fabricated materials i.e. Fe–N–C-Urea (Fe–N–C–U), Fe–N–C- Para- Phenylene Diamine (Fe–N–C- p PD) and Fe–N–C-5-Amino-1-(4′-Aminophenyl)-1,3,3-Trimethylindane (Fe–N–C-AAT) exhibit remarkable peak power densities, reaching as high as 0.96 W cm−2, 0.77 W cm−2 and 0.90 W cm−2, respectively, at a flow rate of 0.4 L min−1 of oxygen and 0.2 L min−1 of hydrogen, keeping the temperature constant at 80 °C. The current work emphasizes the deployment of facile and rapid synthetic protocol coupled with exploiting ingenious organic molecules and avoiding the application of any solvent. [Display omitted] • Adopt microwave-assisted pyrolysis strategy to synthesize distinct Fe–N–C electrocatalysts. • Fe–N–C–U and Fe–N–C-AAT exhibits eminent ORR activity in acidic medium. • The power density of Fe–N–C–U and Fe–N–C-AAT based PEMFC reaches 0.96 and 0.90 W cm−2, respectively. [ABSTRACT FROM AUTHOR]

Photocatalytic oxygen reduction to H2O2 based on g‐C3N4 has presented promising potential for sustainable solar‐fuel production. Yet tuning the timescale of hot electron's lifetime to effectively participate in the surface reactions remains challenging. Here, an electron‐deficient engineering strategy is developed by incorporating an electron‐deficient structure (EDS) with different conjugate regions into large conjugate‐heptazine framework (LCHF) of g‐C3N4 to steer hot electrons of the different timescales to effectively activate O2 for efficient photocatalytic H2O2 production. Femtosecond transientabsorption spectroscopy reveals that introducing EDS into LCHF can steer hot electron rapid transfer to the trapping sites of EDS and notably eliminate the deeply trapped electrons as well as enhance the shallow capture. It is demonstrated that pyromellitic dianhydride not only can tune the lifetime scale of hot electrons but also provide nonpolarized active sites to effectively activate O2 forming H2O2 with lower energy barrier via direct or stepwise 2e− pathways. This photocatalyst achieves an H2O2 yield rate of 25.40 mmol g−1 h−1, enabling an apparentquantumyield of 45.7% at 400 nm and a solar‐to‐chemical efficiency of 2.63%, outperforming the other reported photocatalysts. This work will shed light on the design of organic photocatalysts to tune hot electrons to effectively engage in the surface reaction. [ABSTRACT FROM AUTHOR]

A-site doping with Ca2+, Sr2+ for the cobalt-free BaFeO 3-δ -based cathode materials for proton-conducting ceramic fuel cells (PCFCs) is studied. The composite Ba 0·8 Ca 0·2 FeO 3-δ (BCF0.2)-BaZr 0.1 Ce 0·7 Y 0.1 Yb 0.1 O 3-δ (BZCYYb) and Ba 0·8 Sr 0·2 FeO 3-δ (BSF0.2)-BZCYYb electrode show polarization resistance (R p) of 0.156 Ω cm2 and 0.308 Ω cm2 at 700 °C, respectively. It is found that the Ca or Sr doping not only benefits oxygen vacancy formation and ion migration but also optimizes the surface oxygen reduction reaction (ORR) process. The density functional theory (DFT) calculations show that the Gibbs energies of *OOH and *OH intermediates are decreased, indicating an enhanced surface ORR. The PCFC with BCF0.2-BZCYYb composite cathode achieves the maximum power density of 299.75 mW cm−2 at 700 °C and shows good stability at 650 °C for 65 h under a constant voltage of 0.75 V. These findings suggest that the BCF0.2-BZCYYb has the potential to serve as cobalt-free cathode materials for PCFCs. [Display omitted] • Cobalt-free cubic perovskite Ba 1-x A x FeO 3-δ (A = Ca, Sr) materials are synthesized. • The Ba 0·8 Ca 0·2 FeO 3-δ -BZCYYb symmetrical cell shows low R p of 0.156 Ω cm2 at 700 °C. • DFT calculation reveals the ORR information on BaFeO 3-δ (110) surface doped with Ca or Sr. • The Gibbs energies of *OH and *OOH intermediates are decreased. [ABSTRACT FROM AUTHOR]

Introducing other heteroatom is considered to be a highly effective approach to improve the limited catalytic activity from single nitrogen element doping in nitrogen-doped porous carbon materials. In this work, F and S-modified nitrogen-doped porous carbon (F-S-N-C) is prepared by annealing the assembly material of poly3-fluoro aniline, hydroxyethyl sulfonic acid and g-C 3 N 4 , in which the g-C 3 N 4 is employed as template agent and pore-forming agent. A series of characterization techniques indicate that simultaneous doping of F and the S atoms enhance the electron transfer and construct more defects for N-doped 3D porous carbon, resulting in improved electrocatalytic performance. The prepared F and S-cooperated nitrogen-doped porous carbon (F-S-N-C) exhibits significantly improved oxygen reduction reaction electrocatalytic activity in alkaline media with a half-wave potential of 0.808 V. The zinc-air battery (ZAB) with F-S-N-C as the air cathode catalyst demonstrates a peak power density of 167 mW cm−2, which is higher than that of commercial Pt/C (158 mW cm−2). Moreover, the specific capacity of the F-S-N-C-based ZAB reaches to 817 mAh·g−1. Fluorine and sulfur atoms doped N-doped 3D porous carbon were prepared through one pot method. The best performing electrocatalyst (F-S-N-C) exhibits a half wave potential of 0.808 V in 0.1 M KOH. [Display omitted] • Fluorine and sulfur atoms induced N-doped 3D porous carbon was prepared. • Fluorine and sulfur co-doping promote the generation of abundant active sites. • The zinc air battery with F-S-N-C has high power density and specific capacity. [ABSTRACT FROM AUTHOR]

[Display omitted] The design and development of high-performance and long-life Pt-free catalysts for the oxygen reduction reaction (ORR) is of great important with respect to metal-air batteries and fuel cells. Herein, a new low-cost covalent organic frameworks (COFs)-derived Co N C single-atoms catalyst (SAC) is fabricated and compared with the engineered nanoparticle (NP) counterpart for ORR activity. The ORR performance of the SAC catalyst (Co SA @NC) surpasses the NP counterpart (Co NP -NC) under the same operation condition. Co SA @NC also achieves improved long-term durability and better methanol tolerance compared with the Pt/C. The zinc-air battery assembled by the Co SA @NC cathode delivers a higher power density and energy density than that of commercial Pt/C catalyst. Molecular dynamics (MD) is performed to explain the spontaneous evolution from clusters to single-atom metal configuration and density functional theory (DFT) calculations find that Co SA @NC possesses lower d -band center, resulting in weaker interaction between the surface and the O-containing intermediates. Consequently, the reductive desorption of OH*, the rate-determine step, is further accelerated. [ABSTRACT FROM AUTHOR]

The catalytic efficiency of the cathode is paramount in elevating the operational efficacy of low-temperature solid oxide fuel cells (LT-SOFCs) through expeditious facilitation of the oxygen reduction reaction (ORR). Cathode confronts formidable challenges due to oxygen reduction reaction (ORR) kinetics. This work aims to develop a high-performance cathode by doping strontium (Sr) into Nd 2- x Sr 2 x NiO 4. We synthesized a series of Nd 2- x Sr 2x NiO 4 (x : 0, 0.03, 0.06, 0.1) samples with varying Sr doping levels and evaluated their electrochemical performances. Nd2- x Sr 2 x NiO 4 with optimal ratio (x : 0.06) delivers the highest peak power density of 620–338 mw cm−2 at 550-470 °C among all four samples. The electrochemical impedance spectroscopy of the optimal composition revealed that Nd 2- x Sr 2 x NiO 4 exhibits low electrode polarization resistance of 0.34 Ω cm 2 , depicting its high catalytic performance and compatibility with the electrolyte and anode. Furthermore, XPS spectra also suggest higher surface oxygen vacancies than the other three samples, subsequently improving the conductivity and catalytic activity. Along with high power and OCVs, Nd 2- x Sr 2 x NiO 4 cathode-based SOFC is persistently stable for 40 h without significant degradation. These results conclusively point to demonstrating Nd 2- x Sr 2 x NiO 4 as a high-performing cathode for LT-SOFCs. [ABSTRACT FROM AUTHOR]

The influence of the heterogeneous interface is critical for the catalytic activity of the oxygen reduction reaction (ORR). This study demonstrates an enhancement of the electrocatalytic activity of the SrFe 0.9 Nb 0.1 O 3-δ (SFN113) electrode through the construction of a SrFe 0.9 Nb 0.1 O 3-δ -Sr 3 Fe 1.8 Nb 0.2 O 7-δ (SFN113-SFN327) heterogeneous interface. By coating varying amounts of Sr(NO 3) 2 (0.1 g, 0.2 g and 0.3 g) on SFN113 (1 g), SFN113/327 composite electrodes with different amounts of triple conducting oxide SFN327 are in-situ synthesized by high temperature calcination. Electrical Conductivity Relaxation (ECR) tests show that SFN327 has superior oxygen surface exchange performance compared to SFN113, especially at lower temperatures. At 550 °C, the oxygen surface exchange parameter of SFN327 is 4.23 times higher than that of SFN113. Symmetric cell tests with SFN113/327||BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ (BCZYYb)||SFN113/327 configuration and single cell tests with Ni-BCZYYb||BCZYYb||SFN113/327 configuration indicate that the SFN113/327 composite electrode with a mass ratio of 1:0.2 displays the best electrocatalytic performance, achieving a power output of 502 mW cm−2 at 700 °C. The work not only in-situ synthesizes the SFN113/327 triple conducting composite electrode, but also introduces a novel method for developing proton conducting electrode materials. [ABSTRACT FROM AUTHOR]

It is crucial to develop a non‐precious metal catalyst with high efficiency, affordable cost, and minimal environmental impact for conducting research on the oxygen reduction reaction (ORR) in fuel cells. In this study, BaFe12O19 functional porous carbon (BaFe12O19/PC) nanocomposite was successfully prepared using Fe2O3, BaCO3 and glucose as precursors. Meanwhile, the BaFe12O19/PC catalyst‐modified glassy carbon electrode, carbon rod, and Hg/HgO electrode were used as the working electrode, counter electrode, and reference electrode, respectively, to investigate the electrochemical behavior. The uniform distribution of nano‐scale BaFe12O19 particles in a porous carbon framework was confirmed by field emission scanning electron microscopy characterization. In addition, a double‐layer interface (Fe/Fe3C) was formed between the porous carbon and the nano‐sized BaFe12O19 particles. Fe/Fe3C has a synergistic effect with C, facilitating the migration and transfer of electrons from BaFe12O19 to porous carbon. The BaFe12O19/PC nanocomposite exhibited a four‐electron pathway for electrocatalytic kinetics, showcasing a significantly elevated half‐wave potential of 0.77 V, an impressively reduced Tafel slope of 84.95 mV/dec, and exceptional tolerance towards methanol. It is important to highlight that the BaFe12O19/PC nanocomposite not only possess high catalytic activity for oxygen reduction reactions (ORR), but also demonstrate excellent stability. Consequently, this synthesized BaFe12O19/PC nanocomposite hold promising prospects as cost‐effective and efficient catalysts in fuel cell applications. [ABSTRACT FROM AUTHOR]

The interaction between Pt nanoparticles and their supports, and the Pt nanoparticle size influence the performance and stability of Pt catalysts. Polyaniline (PANI) serves as an effective support for Pt catalysts owing to its abundant functional groups and high electron conductivity. Strong chemical interactions exist between the Pt nanoparticles and the functional groups on PANI. In this study, through the use of different reducing agents, the sizes of Pt nanoparticles on PANI nanofibers are adjusted, resulting in the preparation of three Pt/PANI catalysts. Owing to the strong reducibility of sodium borohydride, its use as a reducing agent leads to rapid heterogeneous nucleation, and the obtained Pt/PANI catalyst exhibits the smallest Pt nanoparticle size among the three Pt/PANI catalysts. Consequently, many Pt nanoparticles are not deposited on the PANI nanofibers, which reduces the activity of the Pt/PANI catalyst. Conversely, when ethylene glycol is used as the reducing agent, the resulting catalyst exhibits the largest Pt nanoparticle size among the three Pt/PANI catalysts owing to the slow reduction rate of Pt4+. The Pt/PANI catalyst prepared using formic acid (Pt/PANI-FA) achieves an optimal reaction rate owing to the moderate reducibility of the reducing agent. Consequently, the Pt nanoparticles on PANI nanofibers in Pt/PANI-FA have a diameter of 3.32 nm, which is comparable to that of Pt nanoparticles in Pt/C catalysts. The half-wave potential of Pt/PANI-FA in the oxygen reduction reaction reaches 840 mV (vs. reversible hydrogen electrode), which surpasses the 801 mV achieved by Pt/C catalysts. [Display omitted] • Polyaniline nanofiber is used as Pt support to prepared three Pt/PANI catalysts. • The size of Pt nanoparticles is tuned by using three different reducing agents. • Compared to sodium borohydride and ethylene glycol, formic acid has optimized reducibility. • The half-wave potential of optimized Pt/PANI catalyst is 840 mV, higher than that of Pt/C. • Chemical interaction between Pt and PANI improves the Pt/PANI catalyst performance. [ABSTRACT FROM AUTHOR]

To replace the noble metal catalysts for oxygen reduction reaction (ORR), a Ni@C-supported N-doped carbon material (Ni@C/NC) is in-situ prepared via one-step pyrolyzing the polymerizable ionic liquid of vinyl imidazole combined with Ni(NO 3) 2. Systemic investigations demonstrate that these nanosized Ni particles are tightly wrapped with a thin carbon layer to form the core/shell structure, meanwhile carbon capsules are synchronously yielded on the carbon matrix. As a result, both the carbon shell and the carbon capsule jointly increase the active sites of the Ni@C/NC, while the carbon shell also contributes the fast electron-transfer from Ni particle. Compared with the normal Ni-supported carbon catalyst, the Ni@C/NC shows the respectable ORR performance with the onset and half-wave potentials of 0.96 and 0.84 V RHE. After the long-term electrocatalysis (10 h), the Ni@C/NC is found to possess the great structural and electrocatalytic stabilities, which maintains 93 % of the initial current density and the well-dispersed and uniform Ni@C particles. Subsequently, a Zn-Air battery with the Ni@C/NC cathode is assembled and exhibits a peak power density of 200 mW cm−2. Therefore, the as-obtained Ni@C/NC with the high electroactivity and stability can be expected as an ideal candidate to apply in the metal-air batteries and fuel cells in the future. Ni particles wrapped with a thin carbon layer is in-situ formed and supported on a N-doped carbon with many capsules, fabricating the Ni@C/NC catalyst, which exhibit the superior catalytic performance for oxygen reduction. [Display omitted] • A Ni@C-supported N-doped carbon material is in-situ prepared. • Nanosized Ni particles are wrapped with a thin carbon layer. • Carbon capsules are synchronously yielded on the carbon matrix. • The Ni@C/NC shows the respectable ORR performance. • The Ni@C/NC possesses the great structural and electrocatalytic stabilities. [ABSTRACT FROM AUTHOR]

The structural tailoring of Pt‐based catalysts into 1D nanowires for oxygen reduction reactions (ORR) has been a focus of research. Mo(CO)6 is commonly used as a morphological modifier to form nanowires, but it is found that it inevitably leads to Mo doping. This doping introduces unique electrochemical signals not seen in other Pt‐based catalysts, which can directly reflect the stability of the catalyst. Through experiments, it is demonstrated that Mo doping is detrimental to ORR performance, and theoretical calculations have shown that Mo sites that are inherently inactive also poison the ORR activity of the surrounding Pt. Therefore, a novel gas‐assisted technique is proposed to replace Mo(CO)6 with CO, which forms ultrafine nanowires with an order of magnitude increase in length, ruling out the effect of Mo. The catalyst performs at 1.24 A mgPt−1, 7.45 times greater than Pt/C, demonstrating significant ORR mass activity, and a substantial improvement in stability. The proton exchange membrane fuel cell using this catalyst provides a higher power density (0.7 W cm−2). This study presents a new method for the preparation of ultra‐long nanowires, which opens up new avenues for future practical applications of low‐Pt catalysts in PEMFC. [ABSTRACT FROM AUTHOR]

The electrochemical production of hydrogen peroxide (H2O2) using metal‐free catalysts has emerged as a viable and sustainable alternative to the conventional anthraquinone process. However, the precise architectural design of these electrocatalysts poses a significant challenge, requiring intricate structural engineering to optimize electron transfer during the oxygen reduction reaction (ORR). Herein, we introduce a novel design of covalent organic frameworks (COFs) that effectively shift the ORR from a four‐electron to a more advantageous two‐electron pathway. Notably, the JUC‐660 COF, with strategically charge‐modified benzyl moieties, achieved a continuous high H2O2 yield of over 1200 mmol g−1 h−1 for an impressive duration of over 85 hours in a flow cell setting, marking it as one of the most efficient metal‐free and non‐pyrolyzed H2O2 electrocatalysts reported to date. Theoretical computations alongside in situ infrared spectroscopy indicate that JUC‐660 markedly diminishes the adsorption of the OOH* intermediate, thereby steering the ORR towards the desired pathway. Furthermore, the versatility of JUC‐660 was demonstrated through its application in the electro‐Fenton reaction, where it efficiently and rapidly removed aqueous contaminants. This work delineates a pioneering approach to altering the ORR pathway, ultimately paving the way for the development of highly effective metal‐free H2O2 electrocatalysts. [ABSTRACT FROM AUTHOR]

The vast number of element combinations and the explosive growth of composition space pose significant challenges to the development of high‐entropy alloys (HEAs). Here, we propose a procedural research method aimed at accelerating the discovery of efficient electrocatalysts for oxygen reduction reaction (ORR) based on Pt‐based quinary HEAs. The method begins with an element library provided by a large language model (LLM), combined with microscale precursor printing and pulse high‐temperature synthesis techniques to prepare multi‐element combination HEA array in one step. Through high‐throughput measurement using scanning electrochemical cell microscopy (SECCM), precise identification of highly active HEA element combinations and exploration of composition space for a specific combination are achieved. Advantageous element combinations are further validated in practical electrocatalytic evaluations. The contributions of individual element sites and the synergistic effects among elements of such HEAs in enhancing reaction activity are elucidated via density functional theory (DFT) calculations. This method integrates high‐throughput experiments, practical catalyst validation, and DFT calculations, providing a new pathway for accelerating the discovery of efficient multi‐element materials in the field of energy catalysis. [ABSTRACT FROM AUTHOR]

The electrochemical production of hydrogen peroxide (H2O2) using metal‐free catalysts has emerged as a viable and sustainable alternative to the conventional anthraquinone process. However, the precise architectural design of these electrocatalysts poses a significant challenge, requiring intricate structural engineering to optimize electron transfer during the oxygen reduction reaction (ORR). Herein, we introduce a novel design of covalent organic frameworks (COFs) that effectively shift the ORR from a four‐electron to a more advantageous two‐electron pathway. Notably, the JUC‐660 COF, with strategically charge‐modified benzyl moieties, achieved a continuous high H2O2 yield of over 1200 mmol g−1 h−1 for an impressive duration of over 85 hours in a flow cell setting, marking it as one of the most efficient metal‐free and non‐pyrolyzed H2O2 electrocatalysts reported to date. Theoretical computations alongside in situ infrared spectroscopy indicate that JUC‐660 markedly diminishes the adsorption of the OOH* intermediate, thereby steering the ORR towards the desired pathway. Furthermore, the versatility of JUC‐660 was demonstrated through its application in the electro‐Fenton reaction, where it efficiently and rapidly removed aqueous contaminants. This work delineates a pioneering approach to altering the ORR pathway, ultimately paving the way for the development of highly effective metal‐free H2O2 electrocatalysts. [ABSTRACT FROM AUTHOR]

The vast number of element combinations and the explosive growth of composition space pose significant challenges to the development of high‐entropy alloys (HEAs). Here, we propose a procedural research method aimed at accelerating the discovery of efficient electrocatalysts for oxygen reduction reaction (ORR) based on Pt‐based quinary HEAs. The method begins with an element library provided by a large language model (LLM), combined with microscale precursor printing and pulse high‐temperature synthesis techniques to prepare multi‐element combination HEA array in one step. Through high‐throughput measurement using scanning electrochemical cell microscopy (SECCM), precise identification of highly active HEA element combinations and exploration of composition space for a specific combination are achieved. Advantageous element combinations are further validated in practical electrocatalytic evaluations. The contributions of individual element sites and the synergistic effects among elements of such HEAs in enhancing reaction activity are elucidated via density functional theory (DFT) calculations. This method integrates high‐throughput experiments, practical catalyst validation, and DFT calculations, providing a new pathway for accelerating the discovery of efficient multi‐element materials in the field of energy catalysis. [ABSTRACT FROM AUTHOR]

Double perovskite oxide Pr 1-x Nd x BaFe 2 O 5+δ (PNBFx, x = 0.0–0.3) nanofiber were prepared using electrospinning and were evaluated as cathodes for solid oxide fuel cells (SOFCs). The crystalline structure, microstructure, and electrochemical performance of PNBFx were thoroughly investigated and discussed. The PNBFx nanofiber cathodes obtained after sintering at 800 °C crystallized in a tetragonal structure with the space group P 4/ mmm and had good chemical compatibility with SDC electrolytes at 900 °C for 4 h. Nd doping was found to increase the lattice parameter, while the average valence of praseodymium and iron content increased steadily in PNBFx. The Pr 0.8 Nd 0.2 BaFe 2 O 5+δ (PNBF02) nanofiber cathode exhibited the best performance with a polarization resistance (R p) of 0.072 Ω cm2 at 750 °C. When PNBF02 nanofiber was used as a single-cell cathode, the peak power density reached 1.52 W cm2 at 750 °C. All results indicate that double perovskite PNBF02 is a promising cathode material for SOFCs. [ABSTRACT FROM AUTHOR]

Alloying platinum with other 3d transition metals (M) in an organized manner is a proven method to enhance the activity and lifespan of Pt catalysts utilized in proton exchange membrane fuel cells (PEMFC). Herein, a distinct composite has been engineered, featuring structured Pt–Fe intermetallic compounds (L1 2 Pt 3 Fe NPs) supported on an iron-doped sulfur-nitrogen-carbon (Fe-SNC) support. The L1 2 Pt 3 FeNPs function as the primary catalytic core for the oxygen reduction reaction (ORR) instead of the conventional Pt NPs. The sulfur atom on the Fe-SNC can secure L1 2 Pt 3 Fe NPs to prevent their aggregation during elevated temperature and operational phases. Additionally, the presence of S atoms can regulate the electronic configuration of platinum and decrease the bond strength between Pt and oxygen-containing intermediates. Consequently, the L1 2 Pt 3 Fe/Fe-SNC catalyst demonstrates exceptional catalytic efficiency and longevity for ORR with E 1/2 of 0.911 V as well as a mass activity (MA) of 0.47 A/mg Pt. The L1 2 Pt 3 Fe/Fe-SNC maintains outstanding ORR stability (MA form 0.47 A/mg Pt to 0.38 A/mg Pt) after 30,000 cycles of AST. Impressively, the L1 2 Pt 3 Fe/Fe-SNC has a power density of 1.547 W/cm2·H 2 –O 2 and 0.669 W/cm2·H 2 -Air at 0.4 V (cathode Pt loading: 0.04mg Pt /cm2) better than commercial Pt/C in PEMFC single-cell. This work provides new ideas for constructing various PtM intermetallic catalysts. [Display omitted] • L1 2 Pt 3 Fe emerges as a major catalytic core for oxygen reduction reactions. • Synergistic effect between L1 2 Pt 3 Fe and Fe-SNC enhances the catalytic activity. • S atoms can anchor L1 2 Pt 3 Fe to enhance catalytic stability. • L1 2 Pt 3 Fe/Fe-SNC shows great ORR performance in PEMFC. [ABSTRACT FROM AUTHOR]

In this article, we have studied the influence of the heat treatment in an inert atmosphere on the structure and catalytic activity of the PtCu/C catalysts with an architecture of bimetallic nanoparticles obtained by a multi-step synthesis method. The transformation of the structure obtained by a multi-step synthesis method into a solid solution during the heat treatment at 350 °C has been shown by the methods of high-resolution TEM and XPS. It has been found that regardless of the type of a carbon support used, the heat treatment leads to an increase in the specific mass activity by 1.4–1.6 times. The increase in the catalytic activity after the heat treatment is achieved due to a change in the chemical composition of the surface and an increase in the degree of alloying of metal components. Due to the combination of the heat treatment and the use of a nitrogen-doped carbon support, we have succeeded in obtaining the PtCu/C catalyst, the ORR activity of which is 6.4 times higher than that of the commercial analog. Testing of the most promising samples as part of the MEA has confirmed the high quality of the materials obtained, the maximum power being 696 W/g (Pt) for the PtCu/C catalyst after the heat treatment. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Catechol‐formaldehyde resin (CFR) is very attractive for H2O2 production via the catalytic process. However, the H2O2 formation is accompanied by the oxidation of catechol groups to o‐benzoquinone groups on CFR, which will cause irreversible damage to CFR and greatly limit its long‐term stable catalytic activity. Herein, CdS/CFR composite photocatalyst with a core‐shell structure was synthesized by hydrothermal method. The photogenerated electrons of CdS are used as a powerful driving force for the reversible redox conversion between catechol groups and o‐benzoquinone groups on the CFR, which not only achieves the long‐term stability of CFR‐catalyzed production of H2O2, but also promotes the separation efficiency of photogenerated e– and h+ in CdS, greatly inhibiting their recombination, so as to maintain CdS stability. The H2O2 yield of CdS/CFR can accumulate to 1.65 mmol·L–1 under visible light for 6 h without sacrificial agent, which is about 3.1 and 2 times that of CdS and CFR, respectively, and CdS/CFR can persist for 10 cycles of photocatalysis (60 h). CdS/CFR also improves the yield of photocatalytic H2O2 by increasing the selectivity of H2O2 and inhibiting its decomposition. This work offers a novel tactic for expanding the application of CFR in photocatalytic generation of H2O2. [ABSTRACT FROM AUTHOR]

With the incorporation of heteroatomic B into single-atom Fe catalyst (Fe SA -NC), a catalyst named Fe SA -BNC with a configuration of Fe-N 3 B 1 had been synthesized for the oxygen reduction reaction (ORR). The low electronegativity of B induced charge redistribution around the active center Fe, thereby modulating the ORR activity. The Fe SA -BNC catalyst demonstrated an outstanding ORR performance in alkaline conditions, with a half-wave potential of 0.87 V. [Display omitted] • Coordination of low electronegativity B with Fe atom. • Regulating the charge states of the active site Fe. • The decrease of the d -band center of Fe promoting the desorption of ORR intermediates and enhancing the ORR performance. Despite extensive research has been conducted on atomic dispersion catalysts for various reactions, altering the electronic structure of the central metal to enhance electrochemical reactivity remains a challenging task. Herein, the electrochemical reactivity was considerably enhanced by introducing heteroatomic B to adjust the d -band of single Fe center. In specific, the obtained Fe SA -BNC catalyst demonstrated an outstanding ORR performance (E 1/2 = 0.87 V) and exhibited greater long-term durability in alkaline media compared to Pt/C. The performance of Fe SA -BNC in Zn–air battery was also higher than that of Pt/C. According to theoretical calculations, a downward shift in the d -band center of Fe was induced by introducing B, thereby improving the desorption of intermediates and facilitating the oxygen reduction reaction (ORR). [ABSTRACT FROM AUTHOR]

Metal-free nanocarbons with highly editable compositions and well-defined morphologies, and adjustable coordination environments have been considered as promising and inexpensive electrode materials that can be used in the fields of fuel cells and metal-air batteries. Herein, the typical micromorphology of high-output tuber crops potato was examined for the first time by cryo-electron microscopy, and nitrogen-doped spherical carbons with highly curved carbon layers were prepared from potato and sweet potato by hydrothermal and ammonia-activated treatments. The potato-derived carbon (PC) and sweet potato-derived carbon (SPC) with enriched nitrogen dopants on native curved carbon layers exhibit favorable oxygen reduction reaction (ORR) activities in both acidic and alkaline media. The half-wave potential of the curved PC is 60 mV higher than that of commercial Pt/C (20 wt% Pt) in 0.1 M KOH. Impressively, the zinc-air battery using the curved PC displays excellent stability and achieves a peak power density of 116 mW cm−2, surpassing the performance of Pt/C (108 mW m−2). Finite element method (FEM) simulations and molecular dynamics (MD) calculations reveal that the curved carbon surface-enhanced tip electric field on the spherical structure, could further induce charge transfer and accelerate the ORR process. This work elucidates the origin of the catalytic activity of spherically structured metal-free carbons with N-doping, providing meaningful insights into the development of low-cost and highly active catalysts and advancing the field of sustainable energy. [Display omitted] • The morphology of potato abundant spherical starch granules was characterized. • Spherical carbons with doped N were constructed by hydrothermal carbonization. • Zinc-air batteries assembled with catalysts have higher power density than Pt/C. • FEM indicates the curved carbon layer enhanced tip electric field accelerate ORR. [ABSTRACT FROM AUTHOR]

The development of high active and stable Pt−M (M=transition metals) electrocatalysts for oxygen reduction reaction (ORR) is crucial for the commercialization of proton exchange membrane fuel cells (PEMFCs). The main challenge of Pt−M electrocatalysts is their instability, mainly due to the leaching of M. In this study, we report the design of P and O co‐doped octahedral PtCo alloy on Ketjen carbon black (Px‐Oct PtCo/C) through a seed‐mediated synthesis. In‐situ FTIR spectroscopy revealed that P0.61‐Oct PtCo/C has the lowest d‐band center, thereby enhancing the catalytic activity. The strong interaction formed by chemical bond between O and Co in Px‐Oct PtCo/C, observed by EXAFS spectra effectively inhibited the dissolution of Co and improved the ORR stability. The mass activity and specific activity of P0.61‐Oct PtCo/C can reach 0.61 A mgPt−1 and 2.4 mA cm−2, respectively, which is 4.1 times and 10.9 times higher than that of commercial Pt/C. After 50,000 potential cycles, the loss of mass activity is only 25 %, surpassing the DOE 2025 target of less than 40 % loss after 30,000 cycles. This study offers an alternative approach to enhancing the activity and durability of Pt−M electrocatalysts for the ORR. [ABSTRACT FROM AUTHOR]

Here, an approach to produce a hierarchical porous Fe‐N‐C@TABOH catalyst with densely accessible high intrinsic active FeNx sites is proposed. The method involves a single‐step pyrolysis of Zn/Fe‐zeolitic imidazolate framework (Zn/Fe‐ZIF‐H) with tetrabutylammonium hydroxide (TABOH) micelles, which is obtained by utilizing TABOH as a structural template and electronic mediator at room temperature for a brief duration of 16 min. Notably, the yield of Zn/Fe‐ZIF‐H is 3.5 times that of Zn/Fe‐ZIF‐N prepared by conventional method. Results indicate that in addition to expediting synthesis and increasing yield of the Zn/Fe‐ZIF‐H, the TABOH induces a hierarchical porous structure and fosters the formation of more and higher intrinsic active FeNx moieties in Fex‐N‐C@TABOH, showing that TABOH is a multifunctional template. Crucially, the increased mesoporosity/external surface area and optimized microenvironment of Fe‐N‐C@TABOH significantly enhance ORR activity by facilitating the formation of high intrinsic active FeNx sites, increasing accessible FeNx sites, and reducing mass transfer resistance. Through structure tailoring and microenvironment optimization, the resulting Fe‐N‐C@TABOH exhibits superior ORR performance. DFT calculation further validates that the synergistic effect of these two factors leads to low ORR barrier and optimized *OH adsorption energy. This study underscores the importance of structure and electronic engineering in the development of highly active ORR catalysts. [ABSTRACT FROM AUTHOR]

Doping–dedoping chemistry lays the cornerstone for converting heteroatom dopants into intrinsic defects as the emerging active sites of carbon catalysts, but the defect content is yet hindered by inadequate doping efficiencies. Comprehending crucial factors behind the doping of pristine carbon and their correlation to the catalytic properties of dedoped carbon is thus of high significance. Here, the overlooked impact of native defects in pristine carbon on dopant‐mediated defect engineering of carbon catalysts is explicitly unveiled. Intact fullerene (C60), C60‐derived carbon, and carbon black in distinct pentagon/edge defect states are employed as respective precursors to undergo a nitrogen doping–dedoping treatment. Theoretical and experimental evidence consistently indicates that native pentagons change the preferred N doping site from the edge to the basal plane, leading to a substantially higher doping level. Importantly, in addition to pentagons from the removal of zigzag‐edged pyridinic N, N dopants in in‐plane pentagons are more easily dedoped than those in hexagons, generating even more pentagons in a new pentagon–heptagon–pentagon structure as oxygen reduction active sites. The optimized defect‐rich carbon gives an outstanding half‐wave potential of 0.834 V (0.846 V for Pt/C) via the four‐electron pathway, excellent long‐term durability, and prospective applicability in zinc–air batteries. [ABSTRACT FROM AUTHOR]

Metal oxides containing La, Mn, and Co cations can catalyze oxygen reduction reactions (ORRs) in electrochemical processes. However, these materials require carbon support and optimal interactions between both compounds to be active. In this work, two approaches to prepare composites of La-Mn-Co-based compounds over carbon xerogel were developed. Using sol-gel methods, either the metal-based material was deposited on the existing carbon xerogel or vice versa. The metal oxide selected was the LaMn0.7Co0.3O3 perovskite, which has good catalytic behavior and selectivity towards direct ORRs. All the as-prepared composites were tested for ORRs in alkaline liquid electrolytes and characterized by diverse physicochemical techniques such as XRD, XPS, SEM, or N2 adsorption. Although the perovskite structure either decomposed or failed to form using those in situ methods, the materials exhibited great catalytic activity, which can be ascribed to the strengthening of the interactions between oxides and the carbon support via C-O-M covalent bonds and to the formation of new active sites such as the MnO/Co heterointerfaces. Moreover, Co-Nx-C species are formed during the synthesis of the metal compounds over the carbon xerogel. These species possess a strong catalytic activity towards ORR. Therefore, the composites formed by synthesizing metal compounds over the carbon xerogel exhibit the best performance in the ORR, which can be ascribed to the presence of the MnO/Co heterointerfaces and Co-Nx-C species and the strong interactions between both compounds. Moreover, the small nanoparticle size leads to a higher number of active sites available for the reaction. [ABSTRACT FROM AUTHOR]

Protonic 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. [ABSTRACT FROM AUTHOR]

Modulating of electronic structure of photocatalyst and integration of dual channel pathway are promising strategy for efficient photosynthesis of hydrogen peroxide (H2O2) from pure water without sacrificial agent and oxygen exposure. In this work, nontoxic aromatic dialdehyde is used to replace the commonly used toxic formaldehyde to form resorcinol‐phthalaldehyde resins through a hydrothermal method. The introducing of aromatic ring as π spacer increases the separation distance of electrons and holes to avoid their recombination. H2O2 can be produced via integrated oxygen reduction reaction (ORR) and water oxidation reaction (WOR) due to the suitable energy band positions and spatially separated reaction sites. Resorcinol‐p‐phthalaldehyde (RP) resin exhibits a promising H2O2 yield of 3351 µmol g−1 h−1 with high apparent quantum yield (AQY) of 14.9% at 420 nm and solar‐to‐chemical conversion (SCC) efficiency of 1.54%. This work provides a simple strategy to modulate the charge separation efficiency and redox reaction pathway on photocatalyst at molecular level design. [ABSTRACT FROM AUTHOR]

High entropy perovskite oxide (HEPO) materials have received significant interest as efficient electrocatalysts owing to their chemical and structural stability, effective interaction of multiple metal active sites with the reaction intermediate species resulting in enhanced catalytic activity. The effect of high‐entropy strategy could achieve the regulation of the structural durability by tailoring the composition. Herein, we design a novel transition metal and rare‐earth metal based high entropy perovskite oxide (Co0.11Mn0.11Ni0.11Fe0.14La0.13Nd0.13Gd0.13Pr0.13)O3, showing superior catalytic activity in the oxygen reduction reaction (ORR) and also promising electrocatalyst in oxygen evolution reaction (OER). High degree of cationic dispersion in the lattice and multiple electrocatalytic active sites enhance the oxygen ion migration at the surface and facilitate electron transfer, manifesting good ORR performance. Notably, the as‐prepared high entropy material exhibits onset and half‐wave potential of 1.02 V and 0.89 V versus RHE, respectively, exceeding the performance of the benchmarked Pt/C catalyst in the ORR process with reasonable redox kinetics. Moreover, the material also presents faster kinetics with reasonably low overpotential and excellent electrochemical stability in the OER process as well. This study shows the viability of designing non‐precious high entropy materials as highly efficient oxide electrocatalyst by utilizing its broad compositional space. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are an emerging crystalline polymer that is constructed by the organic blocks through reversible polymerization. In this review, we have summarized the strategies for designing covalent organic frameworks for the oxygen reduction reaction. The discussion involved the new structural design of COFs and modifications fitting to the applications. Active sites manipulated scale from the single atom's electron states to the body framework arrangements. This review has anticipated the researchers to enlighten new ORR catalyst designing and optimization. [ABSTRACT FROM AUTHOR]

We report Cu, Fe, N‐doped carbon nanotubes, (Cu,Fe)−N−CNT, as electrocatalysts for the oxygen reduction reaction (ORR) in acidic media. (Cu,Fe)−N−CNT was prepared using a silica coating method in pyrolysis to minimize the formation of carbon‐coated metal oxide or carbide nanoparticles, which are known to be inactive for the H2O2 reduction. (Cu,Fe)−N−CNT shows a turnover frequency of 0.66 e− site−1 s−1 at +0.8 V vs. RHE and H2O2 yields of <1 % for the ORR with a utilization factor of active sites of 82 %. Kinetic analysis reveals that 4e− transfer rates for (Cu,Fe)−N−CNT are higher than those of a monometallic counterpart of Fe−N−CNT. In situ X‐ray absorption spectroscopy enables us to determine redox potentials: E°'(FeIII/FeII)=0.65 V vs. RHE and E°'(CuII/CuI)=0.45 V for (Cu,Fe)−N−CNT, and E°'(FeIII/FeII)=0.65 V for Fe−N−CNT. These results indicate that bimetallic doping into carbon nanotubes gives the effect on kinetic parameters but not on thermodynamic ones. In other words, there is no direct electronic interactions between the Cu and Fe active sites for (Cu,Fe)‐N‐CNT because such interactions should modulate their redox potentials. [ABSTRACT FROM AUTHOR]

The strategic regulation of the electronic properties and coordination environment of single‐atom sites through the integration of metal nanoclusters emerges as a promising route to enhance the oxygen reduction reaction (ORR) performance of Fe–N–C materials. Here, a catalyst (FeIn–NC) is successfully developed in which Fe–N–C materials encapsulate Fe–In alloy nanoclusters, and it shows excellent ORR activity and durability under alkaline conditions, with a high half‐wave potential of 0.924 V (vs RHE) and a zinc–air battery power density of 202.1 mW cm−2, superior to commercial Pt/C catalysts. Theoretical calculations unravel that the synergistic interaction between the Fe–In alloy and the FeN4 single‐atom site modifies the electronic structure and charge distribution at the FeN4 site, thereby enhancing the electrocatalytic activity and durability of the ORR. Potential‐dependent microkinetic modeling (MKM) further discloses the ORR mechanisms on the identified FeN4 sites. This work provides a viable strategy for the ORR improvement of Fe–N–C materials via p‐block metal‐based alloy nanoclusters. [ABSTRACT FROM AUTHOR]

Crystalline and soluble 1D linear conjugated polymers (LCPs) have garnered considerable interest as cost‐effective and efficient metal‐free electrocatalysts for the oxygen reduction reaction (ORR) due to their high exposure of catalytic sites and ease of processing. However, difficulties remain in achieving excellent ORR performance for 1D LCPs by conventional molecular design. Herein, it is demonstrated the utilization of quinoidal units as a promising strategy to develop 1D LCPs for ORR. The incorporation of quinoidal unit not only results in polymers with strong inter‐ and intra‐molecular interactions and low‐lying LUMO (lowest unoccupied molecular orbital) energy levels, but also provides polymers with good crystallinity and commendable charge carrier mobilities. The electronic properties of these polymers are fine‐tuned through the introduction of additional heteroatoms and/or substituents in the monomers and comonomers to understand and optimize their ORR catalytic activity. Evaluation of their catalytic performances reveals a remarkable half‐wave potential and limiting current density of up to 0.74 V (vs reversible hydrogen electrod) and 7.50 mA cm−2, respectively. Notably, these performances are achieved without the addition of carbon nanomaterials as support. This study offers a new insight into the design of highly efficient metal‐free organic electrocatalysts. [ABSTRACT FROM AUTHOR]

Metallic aerogels (MAs) with self-supporting three-dimensional (3D) porous structures constitute a potential platform for the construction of robust catalysts. In this work, we successfully constructed 3D PdAu MAs with the optimized d-band electron of Pd and geometrical lattice expansion using a maneuverable in-situ seed-mediated strategy at room temperature. The introduction of Au accelerated the kinetics of Pd 4 Au 3 MAs toward oxygen reduction reaction (ORR), ethylene glycol oxidation reaction (EGOR), and ethanol oxidation reaction (EOR) in alkaline electrolyte, boosting the activity and stability of Pd 4 Au 3 MAs. The mass activities of Pd 4 Au 3 MAs/C in ORR, EGOR and EOR were 1.74, 8.57, and 9.54 A mg Pd −1, respectively, which were remarkably better than those of referenced Pd MAs/C, commercial Pt/C and Pd/C. The rotating ring-disk electrode measurement illustrated that Pd 4 Au 3 MAs/C achieved a 4-electron transfer process in ORR from O 2 to OH−. In-situ Fourier transform infrared spectroscopy revealed that Pd 4 Au 3 MAs/C enabled the cleavage of the C–C bonds, thus accomplishing the C1-complete oxidation of 10-electron ethylene glycol and 12-electron ethanol. This study provides an efficient strategy to fabricate binary non-Pt alloy aerogels as high-performance multifunctional electrocatalysts for ORR, EGOR, and EOR. [Display omitted] • 3D PdAu aerogels were constructed using an in-situ seed-mediated strategy. • ORR mass activity of Pd 4 Au 3 MAs/C was 11.6 and 17.4 times that of Pt/C and Pd/C. • Pd 4 Au 3 MAs/C possessed superior C2 alcohol oxidation properties. • Pd 4 Au 3 MAs/C achieved 4-electron ORR and complete electrooxidation of C2 alcohols. [ABSTRACT FROM AUTHOR]

Significant advancements in the activity of nitrogen‐coordinated iron single‐atom catalysts (Fe–N–C) have attracted attention as potential alternatives to Pt‐based cathodes in proton exchange membrane fuel cells. However, their limited stability in acidic environments hinders their practical application. Moreover, achieving a synchronous enhancement of both the activity and stability of the Fe sites while preventing demetallation or carbon corrosion remains a formidable challenge. Herein, a synthesis method for Fe–N–C is introduced that exhibits remarkable durability, featuring a protective carbon encapsulation formed by applying an additional heterocyclic organic compound coating. It is demonstrated that stability can be enhanced by converting edge‐rich Fe sites into highly stable FeN4 moieties through precise control of the robustness and packing density of the carbon encapsulation. Furthermore, electrochemical redox behavior along with in situ spectroscopies and online differential electrochemical mass spectrometry provide insights into the structural characteristics of each Fe site and their stabilities. The accelerated stress testing and a long‐term test (>100 h) exhibit that the robust carbon encapsulation can successfully prevent corrosion of carbon support and ensure durable Fe sites during operation. [ABSTRACT FROM AUTHOR]

Reversible proton‐conducting solid oxide cells (R‐PSOCs) are considered to be one of the most promising devices for efficient power generation and hydrogen production. However, the requirement of high catalytic activity for fast oxygen reduction/evolution reaction (ORR/OER) and durability under high steam concentration of air electrode materials remains the major challenge for the practical application of R‐PSOCs. Here, a series of cobalt‐free Ruddlesden–Popper perovskite of Nd0.8Sr1.2Ni1‐xFexO4±δ are reported with mixed conductivity for enhanced ORR/OER kinetics. The R‐PSOCs with an optimal Nd0.8Sr1.2Ni0.7Fe0.3O4±δ air electrode show a high peak power density of 1.28 W cm−2 in the fuel cell mode and a promising current density of 3.24 A cm−2 at 1.3 V in the electrolysis cell mode at 700 °C. In addition, the R‐PSOCs show favorable stability under the fuel cell, electrolysis, and reversible modes for hundreds of hours. This work demonstrates that the Ruddlesden–Popper materials can be utilized as suitable air electrodes for R‐PSOCs. [ABSTRACT FROM AUTHOR]

Highly active Pt‐based intermetallic nanoparticles (i‐NPs) loaded on stable supports have garnered considerable interest as promising oxygen reduction reaction (ORR) catalysts for proton‐exchange‐membrane fuel cells (PEMFCs). Herein, thermostable tellurium (Te) is vapor‐deposited onto commercial conductive carbon to anchor high‐temperature‐synthesized Pt3Co i‐NPs. Advanced characterization and density functional theory (DFT) calculations demonstrate that the binding energy of Pt 4f and Co 2p shift positively by 0.12 and 0.95 eV after the introduction of Te in carbon support, promoting the formation of Pt─Te bonds, which enhances the metal–support interactions (MSIs) in Pt3Co/Te‐C (with a more negative binding energy of −10.28 eV). The average size of well‐dispersed Pt3Co i‐NPs (≈3.9 nm) on Te─C is considerably smaller than that of Pt3Co i‐NPs (≈9.1 nm) on commercial carbon. The specific activity of Pt3Co/Te‐C decreases by only 1.5% after 100,000 ultra‐long voltage‐accelerated cycles, while the morphology remains almost unchanged. The membrane electrode assembly using Pt3Co/Te‐C as a cathode demonstrates impressive activity (power density of 2.32 W cm−2@4 A cm−2 and mass activity of 0.50 A mgPt−1@0.9 V) and robust durability (mass activity@0.9 V loss of 26% after 30,000 cycles with intact L12 ordered structure) in H2–O2 operation, significantly exceeding the DOE 2025 requirements. [ABSTRACT FROM AUTHOR]

Activation, break‐in, and/or pre‐treatment protocols are generally applied to energy conversion devices before regular operation to reach stable performance. There remains much to understand about the relationships among physical properties, performance, and electrochemical pre‐treatments. Here, a design‐of‐experiments (DoE) strategy is employed to address this gap by demonstrating the influence of five pre‐treatment parameters for carbon‐supported Pt‐nanoparticle catalysts on the electrocatalytic oxygen reduction reaction (ORR). A subset of pre‐treatments, developed using a central composite design, are tested in a flow cell combined with an inductively‐coupled plasma mass spectrometer (on‐line ICP‐MS). The DoE‐based approach facilitates comprehensive insights from two orders of magnitude fewer experiments than a conventional grid search. The coupled on‐line ICP‐MS setup enables effective catalysis and real‐time catalyst dissolution data. Leveraging insights from DoE for on‐line ICP‐MS and additional characterization, a model is built between the degradation of a multi‐dimensional supported Pt surface, its performance, and applied electrochemical parameters. These investigations identify surface modifications, such as oxidation, and subsequent restructuring of Pt during pre‐treatment as a primary cause of performance deterioration during ORR. By combining DoE with advanced characterization techniques, a powerful approach is demonstrated to gain a mechanistic understanding of pre‐treatment protocols that can be broadly adapted to various reaction chemistries. [ABSTRACT FROM AUTHOR]

Non‐precious metal‐based nitrogen‐doped carbon (M‐Nx/C) shows great potential as a substitute for precious metal Pt‐based catalysts. However, the conventional pyrolytic methods for forming M‐Nx/C active sites are prone to issues such as the lack of synergistic interactions among bimetallic atoms and the potential encasement of active sites, leading to compromised catalytic efficiency and hindered mass transfer. In this work, a highly active FeCo‐N‐C@U‐AC electrocatalyst is developed with a high density of active sites, adequate exposure of catalytic sites, and robust mass transfer capability using the chemical vapor‐phase deposition (CVD) technique. The resulting catalyst demonstrates impressive oxygen reduction reaction (ORR) catalytic performance and stability, with half‐wave potentials of 0.820 V (0.1 M HClO4) and 0.911 V (0.1 M KOH), respectively. It also exhibits significantly enhanced stability, retaining 93.25% and 98.38% of current after continuous 50 000 s of durability testing, surpassing the retention rates of Pt/C (80.31% in HClO4 and 84.96% in KOH electrolytes). Notably, when employed as a cathode catalyst in proton exchange membrane fuel cells (PEMFCs) and zinc‐air flow batteries (ZAFBs), the FeCo‐N‐C@U‐AC catalyst delivers peak power densities of 859 and 162 mW·cm−2, respectively, showcasing competitive performance comparable to benchmark Pt/C. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are promising photocatalysts for H2O2 production from water via oxygen reduction reaction (ORR). The design of COFs for efficient H2O2 production indubitably hinges on an in‐depth understanding of their ORR mechanisms. In this work, taking an imine‐linked COF as an example, we demonstrate that protonation of the functional units such as imine, amine, and triazine, is a highly efficient strategy to upgrade the activity levels for H2O2 synthesis. The protonation not only extends the light absorption of the COF but also provides proton sources that directly participate in H2O2 generation. Notably, the protonation simplifies the reaction pathways of ORR to H2O2, i.e. from an indirect superoxide radical (O2•- ${{O}_{2}^{\bullet -}}$) mediated route to a direct one‐step two‐electron route. Theoretical calculations confirm that the protonation favors H2O2 synthesis due to easy access of protons near the reaction sites that removes the energy barrier for generating *OOH intermediate. These findings not only extend the mechanistic insight into H2O2 photosynthesis but also provide a rational guideline for the design and upgradation of efficient COFs. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are promising photocatalysts for H2O2 production from water via oxygen reduction reaction (ORR). The design of COFs for efficient H2O2 production indubitably hinges on an in‐depth understanding of their ORR mechanisms. In this work, taking an imine‐linked COF as an example, we demonstrate that protonation of the functional units such as imine, amine, and triazine, is a highly efficient strategy to upgrade the activity levels for H2O2 synthesis. The protonation not only extends the light absorption of the COF but also provides proton sources that directly participate in H2O2 generation. Notably, the protonation simplifies the reaction pathways of ORR to H2O2, i.e. from an indirect superoxide radical (O2•- ${{O}_{2}^{\bullet -}}$) mediated route to a direct one‐step two‐electron route. Theoretical calculations confirm that the protonation favors H2O2 synthesis due to easy access of protons near the reaction sites that removes the energy barrier for generating *OOH intermediate. These findings not only extend the mechanistic insight into H2O2 photosynthesis but also provide a rational guideline for the design and upgradation of efficient COFs. [ABSTRACT FROM AUTHOR]

Direct Methanol fuel cells (DMFC) have been limited in their utilization due to their slow cathodic oxygen reduction reaction (ORR) kinetics and the expensive cost of commercial Pt/C catalysts. It is critical to design an oxygen reduction process with high-efficiency catalysts. An approach for modulating the ratio of cellulose, hemicellulose, and lignin in the wheat stalk (WS)/wheat stalk binder (WS binder) precursor materials is proposed in this work. WS binder from alkalization and hydrothermal treatment was added to the WS to change the structure and shape of WS-based carbon materials by varying the ratios, which increased the ORR catalytic activity. The half-wave potential (E 1/2) of the produced carbon material (15 wt% N/C (WS)) is 0.76 V, which was enhanced by 80 mV by adjusting the ratio of the WS/WS binder compared to 0 wt% N/C(WS). The E 1/2 of 15 wt% Fe–N/C (WS) (0.85 V) was greater than that of commercial Pt/C (0.84 V). Besides, its catalytic oxygen reduction process was close to the 4-electron transfer pathway and had good methanol tolerance. The power density obtained with a cathode catalyst of 15 wt% Fe–N/C (WS) for DMFC was 1.39 mW cm−2 at 30 °C and 3.33 mW cm−2 at 60 °C. At different temperatures, the power densities were 1.59 and 1.54 times greater than those of commercial Pt/C catalysts, respectively. [Display omitted] • Binders were added to wheat stalk carbon substrates to change their morphology and structure. • Introduction of Hemin-prepared iron single-atom catalysts with excellent ORR performance. • In DMFC, 15 wt% Fe–N/C(WS) demonstrated a good power density that was better than commercial Pt/C. [ABSTRACT FROM AUTHOR]

Platinum-based intermetallic compounds (IMCs) play a vital role as electrocatalysts in a range of energy and environmental technologies, such as proton exchange membrane fuel cells. However, the synthesis of IMCs necessitates recombination of ordered Pt-M metallic bonds with high temperature driving, which is generally accompanied by side effects for catalysts' structure and performance. In this work, we highlight that semimetal atoms can trigger covalent interactions to break the synthesis-temperature limitation of platinum-based intermetallic compounds and benefit fuel-cell electrocatalysis. Attributed to partial fillings of p-block in semimetal elements, the strong covalent interaction of d-p π backbonding can benefit the recombination of ordered Pt-M metallic bonds (PtGe, PtSb and PtTe) in the synthesis process. Moreover, this covalent interaction in metallic states can further promote both electron transport and orbital fillings of active sites in fuel cells. The semimetal-Pt IMCs were obtained with a temperature 300 K lower than that needed for the synthesis of metal-Pt intermetallic compounds and reached the highest CO-tolerant oxygen reduction activity (0.794 A mg−1 at 0.9 V and 5.1% decay under CO poisoning) among reported electrocatalysts. We anticipate that semimetal-Pt IMCs will offer new insights for the rational design of advanced electrocatalysts for fuel cells. [ABSTRACT FROM AUTHOR]

Proton exchange membrane fuel cells (PEMFCs) have not been applied on a large scale due to their expensive platinum-based catalysts and scarce resources. Metal-nitrogen doped carbon (M-N-C, M=Fe, Ni, Mn, Co) monoatomic catalysts have been considered as promising catalysts for oxygen reduction reaction (ORR), among which Fe-N-C catalysts have high catalytic activity for oxygen reduction in acidic media with low cost. However, most of the reported Fe-N-C catalysts are still not as good as the platinum-based catalysts in fuel cells and have poor stability in acidic media rather than being widely used. Here, we reported a method for constructing Fe-Nx and Co-Nx catalysts on a stable and highly graphitic NC support pyrolyzed from ZIF-67. The obtained Co/Fe-N-C diatomic catalyst achieved an onset potential (Eoneset) of 0.96 V (vs. RHE) and a half-wave potential (E1/2) of 0.79 V (vs. RHE), with more remarkable stability and superior ORR activity compared with the Fe-N-C and Co-N-C catalysts, providing a new insight into enhance the activity and durability of Fe-N-C catalysts. [ABSTRACT FROM AUTHOR]

Due to the large consumption of traditional energy and environmental pollution, it is more and more important to explore efficient and clean new energy sources. Zinc-empty battery has been widely concerned as a kind of green and clean energy, but its slow cathodic oxygen reduction (ORR) reaction limits its large-scale application. Therefore, it is very important to develop an efficient and green economic non-precious metal catalyst for oxygen reduction reaction. In this paper, metal-organic framework (MOF) is used as the precursor, Fe-N doped carbon electrocatalyst (Fe-N-C) was synthesized by high temperature pyrolysis. Fe-N-C catalyst can avoid the aggregation and dissolution of metal atoms due to its strong metal-nitrogen coordination structure, so that the metal atoms are uniformly dispersed on the nitrogen-doped carbon carrier, and achieve high ORR performance. The prepared Fe-N-C-2 catalyst has abundant pore structure and a large number of Fe-NX active sites. The half-wave potential is 0.91 V in alkaline electrolyte and 0.75 V in acidic electrolyte. At the same time, it is applied to zinc-air batteries with an open circuit voltage of up to 1.47 V and a power density of 163.1 mW/cm². This strategy provides a promising approach for designing two-dimensional structures to construct high-performance electrocatalysts. [ABSTRACT FROM AUTHOR]

Minimizing 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 <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. [ABSTRACT FROM AUTHOR]

Two-electron oxygen reduction reaction (2e− ORR) for H2O2 production is regarded as a more ecologically friendly substitute to the anthraquinone method. However, the search of selective and cheap catalysts is still challenging. Herein, we developed a neutral-selective and efficient nonprecious electrocatalyst that was prepared from a commercial activated carbon (AC) by simply microwave-assisted ash impurity elimination and hydrogen peroxide oxidation for surface functional sites optimization. The oxygen configuration can be tuned with enriching carboxyl group up to 6.65 at.% by the dosage of hydrogen peroxide (mass ratio of H2O2/C = ∼0–8.3). Chemical titration experiments identified the carbonyl groups as the most potential active sites, with selectivity boosted by the additional carboxyl groups. The microwave-assisted moderate-oxidized activated carbon (MW-AC5.0) demonstrated optimal 2e− ORR activity and selectivity in neutral electrolyte (0.1 M K2SO4), with H2O2 selectivity reaching ∼75%–97%, a maximum H2O2 production rate (1.90 mol·gcatal−1·h−1@0.1 V) and satisfying faradaic efficiency (∼85%) in gas-diffusion-electrode. When coupled with Fenton reaction, it can degrade a model organic pollutant (methylene blue [MB], 50 ppm) to colorless in a short time of 20 min, indicating the potential applications in the environmental remediation. [ABSTRACT FROM AUTHOR]

Exploring highly active electrocatalysts as platinum (Pt) substitutes for the oxygen reduction reaction (ORR) remains a significant challenge. In this work, single Mn embedded nitrogen-doped graphene (MnN4) with and without halogen ligands (F, Cl, Br, and I) modifying were systematically investigated by density functional theory (DFT) calculations. The calculated results indicated that these ligands can transform the dyz and dxz orbitals of Mn atom in MnN4 near the Fermi-level into d z 2 orbital, and shift the d-band center away from the Fermi-level to reduce the adsorption capacity for reaction intermediates, thus enhancing the ORR catalytic activity of MnN4. Notably, Br and I modified MnN4 respectively with the lowest overpotentials of 0.41 and 0.39 V, possess superior ORR catalytic activity. This work is helpful for comprehensively understanding the ligand modification mechanism of single-atom catalysts and develops highly active ORR electrocatalysts. [ABSTRACT FROM AUTHOR]

Fuel cells as a new type of clean energy, have become the potential alternatives to traditional fossil fuels. Oxygen reduction reaction (ORR) is the cathode procedure of fuel cells. It is of great significance to study more stable and economical high-activity electrocatalysts for the commercial development of fuel cells. Based on the advantages of high entropy effect, this work prepared multiple transition metal co-doped NSC materials (M-NSC, M =Co, Fe, Ni, Mn, Ce), in order to improve the catalytic performance of cathode catalysts. (CeMnFeCoNi)-NSC catalysts with different metal/carbon ratio were synthesized by high-temperature pyrolysis, and the influence of metal addition amounts on the microstructure and catalytic performance were studied. (CeMnFeCoNi)-NSC shows two-dimensional layered structure, providing a larger specific surface area and more active sites. Then (CeMnFeCoNi)NSC was used as the cathode catalyst of direct methanol fuel cells (DMFC) and direct borohydride fuel cells (DBFC), and the peak power densities were 19. 86 and 73.81 m·W cm-2, respectively, Compared with that of Fe-NC based DMFC and DBFC, the peak power densities were 7.92 and 52. 12 m·W cm-2, respectively. The high performance of (CeMnFeCoNi)NSC is mainly attributed to the M-N4 groups formed by metals and nitrogen, and the synergistic effect among multiple metals. Furthermore, it was found that the superior cell performance was achieved with the metal-to-carbon ratio of 1:50. This study provides a new idea for the composition design and performance regulation of carbon-based electrocatalysts. [ABSTRACT FROM AUTHOR]

Developing efficient O2 electrocatalyst is crucial for lithium-oxygen (Li-O2) batteries (LOBs). Among various catalysts, perovskite oxides have exhibited diverse catalytic activity owing to their low synthetic cost, tunable constitutions, flexible structures and excellent electrochemical stability. In this research, LaNi0.5Fe0.5O3 perovskites (LNFO) were synthesized via a classical sol–gel route combined with succedent calcination treatment. The ORR and OER tests indicate that the catalytic activity of LNFO calcined at 600 (LNFO-1) and 800℃ (LNFO-3) is superior to that of 700 (LNFO-2) and 900℃ (LNFO-4). To determine which sample is more suitable as a catalyst for LOBs, the LOBs with LNFO-1 and LNFO-3 electrodes were assembled. The LNFO-1 cathode shows discharge capacity of 1.7686 mAh under the current density of 100 mA g−1, which is higher than that with LNFO-3 cathode. The initial discharge–charge profiles of LOBs with LNFO-1 and LNFO-3 electrodes under a cutoff capacity of 1 mAh at 100 mA g−1 indicates that a lower overpotential could gained from LNFO-1 electrode. Meanwhile, 233 and 93 cycles can be realized under capacity limit of 0.15 and 0.315 mAh, respectively, at the current density of 100 mA g−1. The results demonstrate a lower overpotential, and longer circularity can be implemented in the LOB with LNFO-1 cathode, which can be put down to the larger specific surface area, and more presence of Ni3+ and Fe4+ in LNFO-1. Therefore, our work confirmed that the mesoporous LNFO-1 is a promising electrocatalyst for LOBs. [ABSTRACT FROM AUTHOR]

The ever-growing demand for hydrogen peroxide (H2O2) makes large-scale production via environmentally-friendly strategies necessary. The electrochemical oxygen reduction reaction stands out as an efficient and green approach for H2O2 production. Here, nitrogen-doped mesoporous carbon materials (NMCM) with a hollow semispherical morphology are synthesized for H2O2 generation, which exhibit remarkable electrocatalytic stability, selectivity (94.5%), and onset potential (~ 0.6 V) toward the H2O2 formation in neutral environment. The distinct H2O2 production performance of NMCM can be attributed to synergistic effect of two factors, that is, the pyrrolic N to optimize the work function and the hollow semispherical morphology to facilitate mass transfer and expose abundant electrocatalytic active sites. This work offers a facile way to prepare metal-free electrocatalysts for realizing high-performance H2O2 production in neutral solutions. Nitrogen-doped mesoporous carbon materials with a hollow semispherical morphology and high pyrrolic N contents are synthesized for efficient H2O2 production. [ABSTRACT FROM AUTHOR]