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The generation of above-bandgap photovoltage, referred to as the anomalous photovoltaic effect (APV), is an extraordinary characteristic sought after property in bulk ferroelectric photovoltaic devices. Despite the fact that the relatively narrow bandgap of BiFeO3 (BFO) (2.7 eV) induces a comparatively larger generation of photocurrent than other ferroelectric photovoltaic, it falls short in producing an anomalous photovoltage (Eg ≪ Voc) and exhibits leaky ferroelectric hysteresis due to unavoidable oxygen vacancies. This work revealed a reduction in oxygen vacancies through the substitution of Ba(Fe1/2Nb1/2)O3 in BFO, leading to improved structural, morphological, synchrotron XPS, and electrical properties. This reduction in oxygen vacancies has resulted in an impressive above-bandgap photovoltage (APV) of 4.41 V for 80BFO–20BFN with greater ferroelectric polarization (Pr = 20.45 μC/cm2) observed at the co-existence of polar and non-polar phases. Moreover, both theoretical and experimental optical analyses have demonstrated a significant decrease in the bandgap to 1.92 eV, effectively extending the visible region close to 653 nm. As a result, a larger population of photoexcited charge carriers is generated, enabling the attainment of a high current density (Jsc) of 0.75 μA/cm2 under 100 mW/cm2 light irradiation. [ABSTRACT FROM AUTHOR]

Very recently, open-cage metallo-azafullerenes PbC100N4H4 and Pb2C100N4H4 containing one Pb–N4–C moiety have been synthesized via the electron beam. Herein, we utilized density functional theory calculations in combination with ab initio molecular dynamics (AIMD) simulations to study the geometric and electronic structures, bonding properties, thermodynamic stability, and catalytic performance of MC100N4H4 and M2C100N4H4 (M = Ge, Sn, Pb). Metal–nitrogen distances and metal–metal distances increase along with the metal radius while the metal atom is positively charged. Energy decomposition analysis revealed that the bonding interactions between M and the C100N4H4 fragment could be described as the donor–acceptor interaction between M(ns0(n−1)d10np4) and C100N4H4 fragment, in which the orbital interactions terms contribute more than the electrostatic interactions. AIMD simulations demonstrate that those metallo-azafullerenes exhibit thermodynamic stability at room temperature. These metallo-azafullerenes, which could serve as typical carbon-supported single-atom catalysts, possess enhanced catalytic performance toward the oxygen reduction reaction (ORR) compared to the planar catalysts, which is attributed to the curvature of metallo-azafullerenes. GeC100N4H4 and SnC100N4H4 exhibit high catalytic performance in the 4e-ORR pathway to H2O, whereas only PbC100N4H4 is suitable for the 2e-ORR reaction pathway because of the difficulty in obtaining electrons. All M2C100N4H4 favors the 4e-reaction pathway due to the presence of the axial metal atom. Our finding of open-cage metallo-azafullerenes as efficient single-atom catalysts holds profound implications for both fundamental research in catalysis and practical applications in fuel cells and other electrochemical devices. [ABSTRACT FROM AUTHOR]

We report the free energy barriers for the elementary reactions in the 2e− and 4e− oxygen reduction reaction (ORR) steps on Au(100) in an alkaline solution. Due to the weak adsorption energy of O2 on Au(100), the barrier for the association channel is very low, and the 2e− pathway is clearly favored, while the barrier for the O–O dissociation channel is significantly higher at 0.5 eV. Above 0.7 V reversible hydrogen electrode (RHE), the association channel becomes thermodynamically unfavorable, which opens up the O–O dissociation channel, leading to the 4e− pathway. The low adsorption energy of oxygenated species on Au is now an advantage, and residue ORR current can be observed up to the 1.0–1.2 V region (RHE). In contrast, the O–O dissociation barrier on Au(111) is significantly higher, at close to 0.9 eV, due to coupling with surface reorganization, which explains the lower ORR activity on Au(111) than that on Au(100). In combination with the previously suggested outer sphere electron transfer to O2 for its initial adsorption, these results provide a consistent explanation for the features in the experimentally measured polarization curve for the alkaline ORR on Au(100) and demonstrate an ORR mechanism distinct from that on Pt(111). It also highlights the importance to consider the spin state of O2 in ORR and to understand the activation barriers, in addition to the adsorption energies, to account for the features observed in electrochemical measurements. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR), a pivotal process in hydrogen fuel cells crucial for enhancing fuel cell performance through suitable catalysts, remains a challenging aspect of development. This study explores the catalytic potential of germanene on Al (111), taking advantage of the successful preparation of stable reconstructed germanene layers on Al (111) and the excellent catalytic performance exhibited by germanium-based nanomaterials. Through first-principles calculations, we demonstrate that the O2 molecule can be effectively activated on both freestanding and supported germanene nanosheets, featuring kinetic barriers of 0.40 and 0.04 eV, respectively. The presence of the Al substrate not only significantly enhances the stability of the reconstructed germanene but also preserves its exceptional ORR catalytic performance. These theoretical findings offer crucial insights into the substrate-mediated modulation of germanene stability and catalytic efficiency, paving the way for the design of stable and efficient ORR catalysts for future applications. [ABSTRACT FROM AUTHOR]

Magnetic property (e.g. spin order) of support is of great importance in the rational design of heterogeneous catalysts. Herein, we have taken the Ni-supported ferromagnetic (FM) CrBr3 support (Nix/CrBr3) to thoroughly investigate the effect of spin-order on electrocatalytic oxygen reduction reaction (ORR) via spin-polarized density functional theory calculations. Specifically, Ni loading induces anti-FM coupling in Ni–Cr, leading to a transition from FM-to-ferrimagnetic (FIM) properties, while Ni–Ni metallic bonds create a robust FM direct exchange, benefiting the improvement of the phase transition temperature. Interestingly, with the increase in Ni loading, the easy magnetic axis changes from out-of-plane (2D-Heisenberg) to in-plane (2D-XY). The adsorption properties of Nix/CrBr3, involving O2 adsorption energy and configuration, are not governed by the d-band center but strongly correlate with magnetic anisotropy. It is noteworthy that the applied potential and electrolyte acidity triggers spin-order transition phenomena during the ORR and induces the catalytic pathway change from 4e− ORR to 2e− ORR with the excellent onset potential of 0.93 V/reversible hydrogen electrode, comparable to the existing most excellent noble-metal catalysts. Generally, these findings offer new avenues to understand and design heterogeneous catalysts with magnetic support. [ABSTRACT FROM AUTHOR]

In view of the inherent pseudocapacitance, rich redox pairs (Nb5+/Nb4+ and Nb4+/Nb3+), and high lithiation potential (1.0–3.0 V vs Li/Li+), Nb2O5 is considered a promising anode material. However, the inherent low electronic conductivity of Nb2O5 limits its lithium storage performance, and the rate performance after carbon modification is still unsatisfactory because the intrinsic conductivity of Nb2O5 has not been substantially improved. In this experiment, taking the improvement of the intrinsic electrical conductivity of Nb2O5 as the guiding ideology, we prepared F-doped Nb2O5@fluorocarbon composites (F–Nb2O5@FC) with a large number of oxygen vacancies by one-step annealing. As the anode electrode of lithium-ion batteries, the reversible specific capacity of F–Nb2O5@FC reaches 150 mA g−1 at 5 A g−1 after 1100 cycles, and the rate performance is particularly outstanding, with a capacity up to 130 mA g−1 at 16 A g−1, which is far superior to other Nb2O5@carbon-based anode electrodes. Compared with other single conductivity sources of Nb2O5@carbon-based composites, the electrical conductivity of F–Nb2O5@FC composites is greatly improved in many aspects, including the introduction of free electrons by F− doping, the generation of oxygen vacancies, and the provision of a three-dimensional conductive network by FC. Through analytical chemistry (work function, UV–Vis diffuse reflectance spectroscopy, and EIS) and theoretical calculations, it is proved that F–Nb2O5@FC has high electrical conductivity and realizes rapid electron transfer. [ABSTRACT FROM AUTHOR]

In this work, we have proposed a Continuous Constant Potential Model (CCPM) based on grand canonical density functional theory for describing the electrocatalytic thermodynamics on single atom electrocatalysts dispersed on graphene support. The linearly potential-dependent capacitance is introduced to account for the net charge variation of the electrode surface and to evaluate the free energetics. We have chosen the CO2 electro-reduction reaction on single-copper atom catalysts, dispersed by nitrogen-doped graphene [CuNX@Gra (X = 2, 4)], as an example to show how our model can predict the potential-dependent free energetics. We have demonstrated that the net charges of both catalyst models are quadratically correlated with the applied potentials and, thus, the quantum capacitance is linearly dependent on the applied potentials, which allows us to continuously quantify the potential effect on the free energetics during the carbon dioxide reduction reaction instead of confining it to a specific potential. On the CuN4@Gra model, it is suggested that CO2 adsorption, coupled with an electron transfer, is a potential determining step that is energetically unfavorable even under high overpotentials. Interestingly, the hydrogen adsorption on CuN4@Gra is extremely easy to occur at both the Cu and N sites, which probably results in the reconstruction of the CuN4@Gra catalyst, as reported by many experimental observations. On CuN2@Gra, the CO2RR is found to exhibit a higher activity at the adjacent C site, and the potential determining step is shifted to the *CO formation step at a wide potential range. In general, CCPM provides a simple method for studying the free energetics for the electrocatalytic reactions under constant potential. [ABSTRACT FROM AUTHOR]

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]

Dual-band electrochromic windows have emerged as a promising approach to reduce building energy consumption. However, developing facile and effective method for preparing single-component dual-band electrochromic material remains a challenge. Herein, an in situ carbothermal reduction strategy was utilized to fabricate monoclinic oxygen-deficient tungsten oxide (WO 3-x) for high-performance dual-band electrochromism. Polyvinylpyrrolidone (PVP–K90) underwent transformation into amorphous carbon at high temperature, serving as the reducing agent embedded in the tungsten oxide film, and in situ inducing the formation of oxygen vacancies during annealing treatment. Lastly, the amorphous carbon was gasified without weakening the transmittance of WO 3-x film. The content of oxygen vacancies in WO 3-x could be modulated by controlling the added amount of PVP-K90. The intrinsic generation of oxygen vacancies not only obtained a strong local surface plasmon resonance (LSPR) absorption in near-infrared (NIR) range, but also improved lithium ion (Li+) diffusion in WO 3-x film. The WO 3-x electrochromic film exhibited excellent dual-band electrochromic performance in optical modulation, switching time, coloring efficiency, bistability, and cycle stability. Furthermore, the WO 3-x film was applied to electrochromic window to verify its available regulation in solar illumination and heat, indicating that the designed modification strategy has potential for developing a single-component dual-band electrochromic window with outstanding performance. [ABSTRACT FROM AUTHOR]

To interpret the diffusion behavior of oxygen in epoxy asphalt with different cross‐linking degrees, epoxy asphalt‐oxygen diffusion layer models were constructed. The effect of temperature on oxygen diffusion and the number of oxygen molecules penetrating the epoxy asphalt was quantitatively analyzed. Fick's second law was used to determine the oxygen diffusion coefficient. The Mean square displacement (MSD) was extracted to analyze the effect of cross‐linking degree on the molecular motion of the base asphalt. The results show that as the cross‐linking degree increases, the number of oxygen in the epoxy asphalt decreases, accompanied by a reduction in the oxygen diffusion coefficient. Temperature significantly affects the rate of oxygen diffusion, with higher temperatures leading to greater diffusion depths over the same simulation time. The oxygen diffusion coefficient of epoxy asphalt ranges from 4.60 × 10−11 to 2.20 × 10−10 m2/s at temperatures of 298–373 K. The epoxy system markedly restricts the movement of base asphalt molecules, with saturate being most affected by cross‐linking degree and asphaltene the least. A high cross‐linking network impedes the asphalt‐oxygen contact oxidation, enhancing epoxy asphalt's anti‐aging capacity. These findings provide support for optimizing epoxy asphalt formulations and guiding the development of anti‐oxidant epoxy asphalt. [ABSTRACT FROM AUTHOR]

The unique localized environments (Ni- N -Fe structures and unsaturated O- and N -coordination) due to dual-defect strategy can make the motif more reactive. The N -v Fe -NiFe 2 O 4 /NF catalyst containing N doping and Fe vacancies exhibits overpotentials of 210, 213 and 222 mV at 100 mA cm−2 in 1.0 M KOH, 1.0 M KOH + 0.5 M NaCl and 1.0 M KOH + seawater electrolytes, respectively. [Display omitted] Developing simple and energy-saving pathways to prepare high-efficient and robust non-noble metal based electrocatalysts remains a huge challenge to hydrogen production from seawater electrolysis. Here we demonstrate a facile hydrothermal-calcination-etching approach that simultaneously achieves the required surface N doping and Fe vacancies generation to activate the Ni-O-Fe active motifs in N -v Fe -NiFe 2 O 4 /NF. The unique localized environments (Ni- N -Fe structures and unsaturated O- and N -coordination) due to dual-defect strategy can effectively regulate the electronic structure of the Ni-O-Fe motif to make the motif more reactive. As a result, the N -v Fe -NiFe 2 O 4 /NF catalyst exhibits overpotentials of 210, 213 and 222 mV to deliver 100 mA cm−2 in 1.0 M KOH, simulated seawater and alkaline seawater environments, respectively. Theoretical calculations prove that the Ni-O-Fe structure is the active motif and that the presence of special localized environments can optimize the adsorption of key intermediates on the activated active motifs. [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]

Automated platforms assessing the stability of electrocatalysts are key to accelerate the deployment of clean energy technologies. Here, we present a robust system that allows the study of corrosion behavior in conjunction with the electrochemical protocol and electrolyte composition over many individual electrodes. Oxygen reduction reaction on Pt is used as a proof-of-concept platform, where the influence of the potential window and phosphoric acid (PA) addition on Pt dissolution is probed. A total of 72 hours of automated operation was realized with actions including liquid management, cell cleaning, aliquoting, PA injection, and bubble detection and removal, demonstrating further advancements in automated stability testing for electrocatalysts. [ABSTRACT FROM AUTHOR]

Oxygen reduction reaction via the two-electron pathway (2e− ORR) offers a sustainable opportunity for hydrogen peroxide (H2O2) production, but suffers from low selectivity. In this work, indium oxide with oxygen vacancies (In2O3−x) exhibits a H2O2 selectivity close to 98% at 0.6 V vs. RHE. Further, a Faradaic efficiency (FE) of around 95% at 0.4–0.6 V vs. RHE and a H2O2 productivity of 3.7 mol gcatalyst−1 h−1 are reached in a flow cell. In situ Raman spectra indicate that In2O3−x promotes the adsorption and activation of O2 and stabilizes oxygen intermediates. This work provides an insight into improving H2O2 selectivity for 2e− ORR catalysts. [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]

In this work, a high density of dispersed Co9S8 nanoparticles (NPs) loaded in carbon aerogels as bi-catalysts (Co9S87.5NP/CA catalysts) were successfully prepared by virtue of the seeded-growth method that is widely used for the synthesis of noble metal NPs. It is found that the optimal molar ratio of Co2+-to-Fe3+ ions for the formation of a high density of dispersed Co9S8 NPs with average sizes of 90 nm is determined to be 7.5 (represented by the superscript number) at the fixed concentration of tannic acid (TA) ([TA] : [Fe3+] = 1 : 1). Moreover, the concentration of Fe3+ precursors is the key that can guarantee the formation of dispersed Co9S8 NPs by the overgrowth of in situ Fe SA-NCs as seeds by the spatial confinement effect during the pyrolysis. Thanks to the multiple valence states of elemental Co in the Co9S8 NPs and their good dispersity in the as-prepared Co9S87.5NP/CA catalysts, the half-wave potential (E1/2) and the overpotential at 10 mA cm−2 (η10) towards the alkaline oxygen reduction reaction (ORR) and the acidic hydrogen evolution reaction (HER) can be improved up to 0.891 V and 177 mV, respectively. [ABSTRACT FROM AUTHOR]

The commercialization of magnesia–air batteries (Mg–air) necessitates the development of highly efficient, cost-effective, and durable electrocatalysts for the oxygen reduction reaction (ORR), replacing expensive and unstable precious metal electrocatalysts. A hard template-assisted synthesis of FeCo nanoparticles immobilized on N-doped porous carbon (Fe–Co–C–N) for the ORR is reported. The half-wave potential of Fe–Co–C–N for ORR (E1/2 = 0.88 V vs. RHE) is elevated by 40 mV compared to that of 20 wt% Pt/C (E1/2 = 0.84 vs. RHE). The catalyst exhibits exceptional catalytic performance and remarkable stability. The discharge voltage of the Mg–air battery, utilizing Fe–Co–C–N as the cathode catalyst (1.29 V), surpasses that of the battery employing 20 wt% Pt/C as the cathode catalyst (1.28 V). The Mg–air battery with Fe–Co–C–N as the cathode catalyst exhibited excellent discharge stability and maintained a stable discharge for over 200 hours. The present study offers valuable insights into the structural design and regulatory mechanisms governing the performance of M–N–C catalysts in Mg–air batteries. [ABSTRACT FROM AUTHOR]

The incorporation of an iron source into NH2-MOF-5, followed by thermal decomposition, yields a porous metal–carbon catalyst (MOF5A-Fe@NC). This catalyst possesses significant N content, a high degree of graphitization, and abundant Fe–Nx sites, which contribute to enhanced oxygen reduction. Specifically, the obtained MOF5A-Fe@NC demonstrates a positive onset potential (0.972 V), a substantial limiting current density (4.815 mA cm−2), and a small Tafel slope (58.7 mV dec−1), and maintains a high current retention of 96.3% after 10 hours. [ABSTRACT FROM AUTHOR]

Metal halide perovskites with suitable energy band structures and excellent visible-light responses have emerged as promising photocatalysts for CO2 reduction to valuable chemicals and fuels. However, the efficiency of CO2 photocatalytic reduction often suffers from inefficient separation and sluggish transfer. Herein, a step-scheme (S-scheme) CsPbBr3/BiOBr photocatalyst with oxygen vacancies possessing intimate interfacial contact was fabricated by anchoring CsPbBr3 QDs on BiOBr-Ov nanosheets using a mild anti-precipitation method. The results showed that CsPbBr3/BiOBr-Ov-2 with an internal electric field (IEF) heterojunction exhibited a boosted evolution rate of 27.4 μmol g−1 h−1 (CO: 23.8 μmol g−1 h−1 and CH4: 3.6 μmol g−1 h−1) with an electron consumption rate (Relectron) of 76.4 μmol g−1 h−1, which was 5.9 and 3.2 times that of single CsPbBr3 and BiOBr-Ov, respectively. Density functional theory (DFT) calculations revealed that BiOBr with oxygen vacancies can effectively enhance the adsorption and activation of CO2 molecules. More importantly, in situ infrared Fourier transform spectroscopy (DRIFTS) spectra show the transformation process of the surface species, while the femtosecond transient absorption spectrum (fs-TA) reveals the charge transfer kinetics of the CsPbBr3/BiOBr-Ov. Overall, this work provides some guidance for the rational design of S-scheme heterojunctions and vacancy-engineered photocatalysts, which are expected to have potential applications in the fields of photocatalysis and solar energy conversion. [ABSTRACT FROM AUTHOR]

Due to the challenge of cleaving O−O bonds at single Co sites, mononuclear Co complexes typically show poor selectivity for the four‐electron (4e−) oxygen reduction reaction (ORR). Herein, we report on selective 4e− ORR catalyzed by a Co porphyrin with a hanged ZnII ion. Inspired by Cu/Zn‐superoxide dismutase, we designed and synthesized 1‐CoZn with a hanging ZnII at the second sphere of a Co porphyrin. Complex 1‐CoZn is much more effective than its Zn‐lacking analogues to catalyze the 4e− ORR in neutral aqueous solutions, giving an electron number of 3.91 per O2 reduction. With spectroscopic studies, the hanging ZnII was demonstrated to be able to facilitate the electron transfer from CoII to O2, through an electronic "pull effect", to give CoIII‐superoxo. Theoretical studies further suggested that this "pull effect" plays crucial roles in assisting O−O bond cleavage. This work is significant to present a new strategy of hanging a ZnII to improve O2 activation and O−O bond cleavage. [ABSTRACT FROM AUTHOR]

In situ growth of intertwined trinuclear copper complexes (nCu3) on a cellulose-derived carbon support (CMC) produced a high-performance electrocatalyst (CMC–nCu3) for the oxygen reduction reaction (ORR), which demonstrated superior performance in zinc–air batteries compared to a commercial Pt/C catalyst. This work highlights the importance of copper-based molecular catalysts with rich and intertwined tricopper structures for boosting both ORR activity and stability. [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 work, we developed a direct strategy to fabricate Palladene (i. e. Palladium metallene) aerogels and propose a temperature‐dependent growth mechanism. Besides the typical three‐dimensional networks and wrinkled surface morphologies, the as‐prepared Palladene50 ${{Palladene}_{50}}$ aerogel is endowed with abundant Pd2+. The as‐prepared Palladene50 ${{Palladene}_{50}}$ aerogel exhibits an excellent mass activity in the formic acid oxidation reaction and a good half‐wave potential in the oxygen reduction reaction in comparison with Pd/C and a Pd aerogel. This work expands the range of metal aerogels from the perspective of the building block units and demonstrates a direct approach to fabricate highly promising bifunctional electrocatalysts for fuel cells. [ABSTRACT FROM AUTHOR]

The design of non-metallic electrocatalysts with high activity and prolonged durability in alkaline environments is essential for the development of efficient, cost-effective and simplified electrocatalytic oxygen reduction systems. Layer-restacking is the bottleneck restricting its ion dynamics and active site exposure, and carbon dot (CD) intercalation MXene can prevent layers of MXene restacking. Here, we report a novel MXene/CD composite composed of layered MXene templates and zero-dimensional carbon dot particles. The composite material was synthesized by the strong interaction between CD and MXene core. In the process of mutual combination, CD can be embedded into MXene nanosheets, increasing the interlayer spacing and promoting the electrolytic diffusion between MXene sheets. Therefore, MXene/CD nanodot hybrids exhibit good ORR catalytic activity. In 0.1 M KOH solution, the half-wave potential of MXene/CD was 0.78 V, and diffusion limiting current density was 5.6 mA cm−2. Additionally, after 50,000 s of cyclic operation tests, the relative current density has decayed by only 3.8%, demonstrating excellent stability. [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]

• The stronger electronegativity of Ag in Ag/Co 3 O 4 led to richer surface Co3+. • Ag/Co 3 O 4 gained by Ag-reduction method showed higher surface Co3+/Co2+ ratio. • The reducibility of Co 3 O 4 was greatly improved by the loading of Ag via reduction method. • Ag/Co 3 O 4 prepared by Ag-reduction method showed higher catalytic activity. Silver (9 wt.%) was loaded on Co 3 O 4 -nanofiber using reduction and impregnation methods, respectively. Due to the stronger electronegativity of silver, the ratios of surface Co3+/Co2+ on Ag/Co 3 O 4 were higher than on Co 3 O 4 , which further led to more adsorbed oxygen species as a result of the charge compensation. Moreover, the introducing of silver also obviously improved the reducibility of Co 3 O 4. Hence the Ag/Co 3 O 4 showed better catalytic performance than Co 3 O 4 in benzene oxidation. Compared with the Ag/Co 3 O 4 synthesized via impregnation method, the one prepared using reduction method (named as AgCo-R) exhibited higher contents of surface Co3+ and adsorbed oxygen species, stronger reducibility, as well as more active surface lattice oxygen species. Consequently, AgCo-R showed lowest T 90 value of 183°C, admirable catalytic stability, largest normalized reaction rate of 1.36 × 10−4 mol/(h·m2) (150°C), and lowest apparent activation energy (E a) of 63.2 kJ/mol. The analyzing of in-situ DRIFTS indicated benzene molecules were successively oxidized to phenol, o-benzoquinone, small molecular intermediates, and finally to CO 2 and water on the surface of AgCo-R. At last, potential reaction pathways including five detailed steps were proposed. [ABSTRACT FROM AUTHOR]

Unveiling the dynamic active site of defective carbon-based electrocatalysts for hydrogen peroxide production. [Display omitted] Defective carbon materials have emerged as promising candidates for the electrocatalysis of oxygen reduction reaction (ORR) to selectively produce H 2 O 2. However, distinguishing the roles of oxygenates and carbon defects in carbon for 2e- ORR remains to be challenging. In a recent issue of Nature Communications, Yao and coworkers pinpointed the major active sites in oxygenated carbon materials and identified the key intermediate employing a series of dynamic and simulation techniques. In addition to highlight the proposed work, this comment article also discussed pioneering methodologies to characterize structure dynamics and probe the integral active center for rational design of carbon based catalysts with atomic precision. [ABSTRACT FROM AUTHOR]

The goal of this research was to assess the efficiency of the liquid digestate treatment conducted with algal, environmental isolates illuminated entirely with sunlight. The photobioreactor was exposed to natural conditions and evaluated based on the reduction of chemical oxygen demand (COD), nitrogen compounds, and soluble phosphates. Microalgal and bacterial communities growing during the treatment process were studied. A high removal rate of soluble COD (= 91%) and nutrients (= 86%) was achieved. The average concentrations of nitrogen, phosphates, and COD in the reactor effluent were 95 mgN/L, 49 mg/L, and 735 mg O2/L, respectively. The overall algae-bacteria biomass productivity of 22 mg/L/d, calculated on the total suspended solids (TSS) basis, was recorded. The microbial analysis revealed the dominance of Tetradesmus obliquus followed by Microglena sp. in the first 14 weeks of the experiment. At the end of the experimental run, Chlorella sorokiniana cells appeared as a result of illumination intensity changes. The dominating bacteria belonged to Firmicutes (26.31%), Patescibacteria (17.38%), and Actinobacteriota (14.86%) and could have been responsible for the transformation of nitrogen and oxidation of organic contaminants. The research demonstrated that natural sunlight can successfully be used for efficient liquid digestate treatment with the algae-bacterial community. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR), occurred at cathodes in fuel cells, eco-friendly energy-conversion system, requires efficient electrocatalysts to overcome sluggish reaction kinetics. In this work, to enhance the ORR performance by decreasing potentials, we developed carbonized zeolite-imidazolate frameworks (ZIF) containing Co atoms (Co–C). The final product is produced by two-step process including (i) the formation of ZIF with Co species, and (ii) carbonization of the ZIF using high temperature treatment. Morphological characterizations revealed that the Co–C has polygon-shaped ZIF-based materials with metallic Co particles wrapped by layered carbon structures. The amount of Co atoms is found to be ~ 4 wt%, possessing a large surface area of 718 m2/g. X-ray photoelectron spectroscopy measurements further supported the formation of sp2 carbon structures with N-doping. The Co–C products exhibit an efficient electrocatalytic ORR performance in alkaline media, with their onset and half-wave potentials as of 0.97 and 0.86 V, comparable to those of Pt/C. Furthermore, Co–C shows the excellent cyclic durability and stability against for methanol poisoning. Collectively, this system including Co-based active species on ZIF networks provides a promise route for the development of efficient ORR electrocatalysts. [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]

[Display omitted] • MoAl 1-x B MBene is demonstrated to be a robust support for loading Ru nanoparticles. • Ru/MoAl 1-x B achieves the superior catalytic performance towards hydrogen generation. • Mechanism of AB hydrolysis over Ru/MoAl 1-x B is systematically investigated. • This is a first example to demonstrate MBene for boosting AB hydrolysis. The coordination between carrier and active metal is critical to the catalytic efficiency of ammonia borane (AB) hydrolysis reaction. In the present study, we report a new type of catalytic support based on molybdenum boride (MBene) MoAl 1-x B and demonstrate that the effective combination of MoAl 1-x B with Ru nanoparticles can realize the significantly enhanced performance for hydrogen generation. Owing to the efficient activation and dissociation of reactants, the optimal Ru/MoAl 1-x B catalyst achieves the large turnover frequency of 494 mol H2 mol Ru -1 min−1, high hydrogen generation rate of 119817 mL min−1 g Ru -1 and favorable apparent activation energy of 39.2 kJ mol−1 for the catalytic hydrolysis of AB under alkaline-free condition. The isotopic test suggests the cleavage of O H bond in H 2 O is the rate-determining step for hydrolysis reaction, while the fracture of B–H bond in AB is also well revealed by attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectroscopy. Significantly, the flexible on-demand hydrogen generation is achieved by using chemical switches for on–off AB hydrolysis. This study provides a new support platform based on two-dimensional MBene to exploit efficient catalysts to boost AB dehydrogenation. [ABSTRACT FROM AUTHOR]

In this work, pyroelectric materials can spontaneously polarize and generate an internal electric field when heated, and the photocatalyst will have band bending under the action of the internal electric field, which promotes the separation of photogenerated carriers. When HCN@PVTC@CdS is used as a photocathode pole, due to the presence of internal electric field generated by pyroelectric effect, the photocatalyst attached to the pyroelectric material will be affected, and its energy band will bend, which is conducive to the separation of photogenerated charge carriers, accelerating the reaction kinetics of the battery. [Display omitted] Zinc–air battery as one of the new generations of battery system, its theoretical specific energy is as high as 1086 Wh kg−1, specific capacity up to 820 mAh/g, and zinc has the advantages of environmental friendliness, resource abundance, low cost and good safety, so it has attracted much attention. However, due to its slow reaction kinetic process, zinc–air battery will produce a large charging overpotential usually up to 2 V, it is far beyond the theoretical voltage of 1.65 V, so reducing the overpotential of zinc–air batteries is extremely necessary, and the most common way to solve this problem is to use excellent catalyst cathode to improve the oxygen reduction and oxygen evolution kinetics of zinc–air batteries. So we developed a new photothermal assisted zinc–air battery system with Hollow carbon nanosphere@poly (vinylidene fluoride-trifluoroethylene-chlorofluoroethylene)@CdS (HCN@PVTC@CdS) photocathode, the pyroelectric and photocatalysis effect can effectively promote the reaction kinetics and reduce the reaction overpotential. With the pyroelectric and photocatalysis synergistic effect, the zinc–air has displayed a high discharge potential of 1.33 V and a low charging potential of 1.5 V with good cycle stability. This multi-assist technology with built-in electric and light fields paves the way for the development of high-performance zinc–air batteries and other energy storage systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • A unique 1D/2D hierarchical structure is successfully constructed. • The catalyst exhibits superhydrophilicity and superaerophobicity. • The as-prepared catalyst displays outstanding performance for HER and UOR. Utilizing the thermodynamically favorable urea oxidation reaction instead of the anodic oxygen precipitation reaction is an alternative pathway for the energy-saving hydrogen production. Therefore, it is significant to explore advanced electrocatalysts for both HER and UOR. In this work, a dendritic heteroarchitectures of 2D CoMoO 4 nanosheets deposited on 1D CoP nanoneedles (CoP/CoMoO 4 -CC) was fabricated as bifunctional electrocatalyst. 1D CoP nanostructure with fast charge transport pathways and 2D CoMoO 4 nanostructure with large specific surface area and short paths for electron/mass transport. The unique morphology endows the superhydrophilic and superaerophobic properties, allowing for the rapid contact with the reactants and rapid removal of surface-generated gases. As a result, the CoP/CoMoO 4 -CC shows efficient bifunctional activity. This work offers a new avenue to rationally design bifunctional electrocatalysts for large-scale practical hydrogen production. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts (SACs) have received significant interest for optimizing metal atom utilization and superior catalytic performance in hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). In this study, we investigate a range of single‐transition metal (STM1 = Sc1, Ti1, V1, Cr1, Mn1, Fe1, Co1, Ni1, Cu1, Zr1, Nb1, Mo1, Ru1, Rh1, Pd1, Ag1, W1, Re1, Os1, Ir1, Pt1, and Au1) atoms supported on graphyne (GY) surface for HER/OER and ORR using first‐principle calculations. Ab initio molecular dynamics (AIMD) simulations and phonon dispersion spectra reveal the dynamic and thermal stabilities of the GY surface. The exceptional stability of all supported STM1 atoms within the H1 cavity of the GY surface exists in an isolated form, facilitating the uniform distribution and proper arrangement of single atoms on GY. In particular, Sc1, Co1, Fe1, and Au1/GY demonstrate promising catalytic efficiency in the HER due to idealistic ΔGH* values via the Volmer‐Heyrovsky pathway. Notably, Sc1 and Au1/GY exhibit superior HER catalytic activity compared to other studied catalysts. Co1/GY catalyst exhibits higher selectivity and activity for the OER, with an overpotential (0.46 V) comparable to MoC2, IrO2, and RuO2. Also, Rh1 and Co1/GY SACs exhibited promising electrocatalysts for the ORR, with an overpotential of 0.36 and 0.46 V, respectively. Therefore, Co1/GY is a versatile electrocatalyst for metal‐air batteries and water‐splitting. This study further incorporates computational analysis of the kinetic potential energy barriers of Co1 and Rh1 in the OER and ORR. A strong correlation is found between the estimated kinetic activation barriers for the thermodynamic outcomes and all proton‐coupled electron transfer steps. We establish a relation for the Gibbs free energy of intermediates to understand the mechanism of SACs supported on STM1/GY and introduce a key descriptor. This study highlights GY as a favorable single‐atom support for designing highly active and cost‐effective versatile electrocatalysts for practical applications. [ABSTRACT FROM AUTHOR]

In a unified regenerative fuel cell (URFC) or reversible fuel cell, the oxygen bifunctional catalyst must switch reversibly between the oxygen reduction reaction (ORR), fuel cell mode, and the oxygen evolution reaction (OER), electrolyzer mode. However, it is often unclear what effect alternating between ORR and OER has on the electrochemical behavior and physiochemical properties of the catalyst. Herein, operando X‐ray absorption spectroscopy (XAS) is utilized to monitor the continuous and dynamic evolution of the Co, Mn, and Fe oxidation states of perovskite catalysts Ba0.5Sr0.5Co0.8Fe0.2O3‐δ (BSCF) and La0.4Sr0.6MnO3‐δ (LSM), while the potential is oscillated between reducing and oxidizing potentials with cyclic voltammetry. The results reveal the importance of investigating bifunctional catalysts by alternating between fuel cell and electrolyzer operation and highlight the limitations and challenges of bifunctional catalysts. It is shown that the requirements for ORR and OER performance are divergent and that the oxidative potentials of OER are detrimental to ORR activity. These findings are used to give guidelines for future bifunctional catalyst design. Additionally, it is demonstrated how sunlight can be used to reactivate the ORR activity of LSM after rigorous cycling. [ABSTRACT FROM AUTHOR]

The undesirable capacity loss after first cycle is universal among layered cathode materials, which results in the capacity and energy decay. The key to resolving this obstacle lies in understanding the effect and origin of specific active Li sites during discharge process. In this study, focusing on Ah‐level pouch cells for reliability, an ultrahigh initial Coulombic efficiency (96.1%) is achieved in an archetypical Li‐rich layered oxide material. Combining the structure and electrochemistry analysis, we demonstrate that the achievement of high‐capacity reversibility is a kinetic effect, primarily related to the sluggish Li mobility during oxygen reduction. Activating oxygen reduction through small density would induce the oxygen framework contraction, which, according to Pauli repulsion, imposes a great repulsive force to hinder the transport of tetrahedral Li. The tetrahedral Li storage upon deep oxygen reduction is experimentally visualized and, more importantly, contributes to 6% Coulombic efficiency enhancement as well as 10% energy density improvement for pouch cells, which shows great potentials breaking through the capacity and energy limitation imposed by intercalation chemistry. [ABSTRACT FROM AUTHOR]

Elucidation the relationship between electrode potentials and heterogeneous electrocatalytic reactions has attracted widespread attention. Herein we construct the well-defined Mn single-atom (MnSA) catalyst with four N-coordination through a simple thermal pyrolysis preparation method to investigate the electrode potential micro-environments effect on carbon dioxide reduction reactions (CO2RR) and oxygen reduction reactions (ORR). MnSA catalysts generate higher CO production Faradaic efficiency of exceeding 90% at −0.9 V for CO2RR and higher H2O2 yield from 0.1 to 0.6 V with excellent ORR activity. Density functional theory (DFT) calculations based on constant potential models were performed to study the mechanism of MnSA on CO2RR. The thermodynamic energy barrier of CO2RR is lowest at −0.9 V vs. reversible hydrogen electrode (RHE). Similar DFT calculations on the H2O2 yield of ORR showed that the H2O2 yield at 0.2 V was higher. This study provides a reasonable explanation for the role of electrode potential micro-environments. [ABSTRACT FROM AUTHOR]

To enhance the performance and widespread use of solid oxide fuel cells (SOFCs), addressing the low-temperature (< 650 °C) electrochemical performance and operational stability issues of cathode materials is crucial. Here, we propose an innovative approach to enhance oxygen ion mobility and electrochemical performance of perovskite oxide by substituting some oxygen sites with chlorine anions. The designed SrTa0.1Fe0.9O3-δ-xClx (x = 0.05 and 0.10) exhibits improved performance compared to SrTa0.1Fe0.9O3-δ (STF). SrTa0.1Fe0.9O2.95-δCl0.05 (STFCl0.05) shows the lowest area-specific resistance (ASR) value on Sm0.2Ce0.8O1.9 (SDC) electrolyte. At 600 °C, STFCl0.05 achieves an ASR value of 0.084 Ω·cm2, and a single cell with STFCl0.05 reaches a higher peak power density (PPD) value (1143 mW·cm-2) than that with STF (672 mW·cm-2). Additionally, besides exhibiting excellent oxygen reduction reaction (ORR) activity at lower temperatures, the STFCl0.05 cathode demonstrates good CO2 tolerance and operational stability. Symmetrical cell operation lasts for 150 h, and single cell operation endures for 720 h without significant performance decline. The chlorine doping approach effectively enhances ORR activity and stability, making STFCl0.05 a promising cathode material for low-temperature SOFCs. [ABSTRACT FROM AUTHOR]

The electrochemical co‐synthesis of H₂O₂ and O₃ holds substantial potential for environmental sustainability and energy conservation. However, synthesizing electrocatalysts with appropriate adsorption energies for intermediates in the electrochemical pairwise electrosynthesis of H₂O₂ and O₃ remains a major challenge. In this study, boron and nitrogen‐doped 2D diamonds (BND) and atomically dispersed Pt₁/BND electrocatalysts are systematically designed and synthesized to facilitate the two‐electron oxygen reduction reaction (2e⁻ ORR) and electrochemical ozone production (EOP), respectively. The BND and Pt₁/BND electrocatalysts exhibit remarkable electrochemical activity, with BND achieving 90.7% selectivity for H₂O₂ and Pt₁/BND attaining a Faradaic efficiency (FE) of 12.54% for EOP. The Pt monatomic species, with a loading of 0.13%, are predominantly distributed along the edges of the Pt₁/BND. Theoretical calculations reveal that their superior properties primarily stem from the phase transition to graphene fractions at the edges, which facilitate moderate adsorption of oxygen intermediates and modulate the electronic structure through synergistic interactions between the dopant elements. Additionally, the 2D diamonds exhibit favorable mass transfer properties. The integration of H₂O₂ and O₃ for the synergistic degradation of organic contaminants and sterilization further showcase the practical utility of BND and Pt₁/BND electrocatalysts. [ABSTRACT FROM AUTHOR]

The Co-based perovskite of SrNb 0.1 Co 0.7 Fe 0.2 O 3-δ (SNCF) stands out for its high intrinsic catalytic activity toward the oxygen evolution reaction (OER) in the alkaline solution. However, the low catalytic activity of SNCF toward the oxygen reduction reaction (ORR) restricts its application in the zinc-air batteries (ZABs). To address this issue, we develop the oxygen vacancy enriched heterostructure (SNCF–NF–Co 3 O 4 @N 2) including the SNCF nanofibers with the diameter of 80 nm and Co 3 O 4 nanoparticles anchored on the SNCF surface by electrospinning and sintering in N 2. Due to the high charge/reactant transfer rate, Co3+/Co2+ ratio and oxygen vacancy concentration, SNCF-NF-Co 3 O 4 @N 2 demonstrates the superior bifunctional oxygen catalytic activity. Specially, the ORR half-wave potential can reach 0.69 V, and the OER potential at 10 mA cm−2 is as low as 1.57 V. Remarkably, the aqueous and solid-state ZABs with SNCF-NF-Co 3 O 4 @N 2 exhibit the high peak power densities of 181.2 and 73.3 mW cm−2, respectively. Furthermore, SNCF-NF-Co 3 O 4 @N 2 based ZAB demonstrates an impressive energy efficiency of 79.6%. This study introduces an innovative strategy for enhancing the bifunctional oxygen catalytic performances of Co-based perovskites. [Display omitted] • SNCF-NF-Co 3 O 4 @N 2 heterostructure is prepared by electrospinning followed by sintering in N 2. • SNCF-NF-Co 3 O 4 @N 2 has the abundant oxygen vacancies and high Co3+/Co2+ ratio. • SNCF-NF-Co 3 O 4 @N 2 demonstrates the superior ORR/OER catalytic activities and stabilities. • The ZABs with SNCF-NF-Co 3 O 4 @N 2 show the high reversibility and cycling stability. [ABSTRACT FROM AUTHOR]

Oxides with the same structure as K 2 NiF 4 have received increasing interest in reversible solid oxide cells (RSOCs) because of the unique advantages of low thermal expansion efficient (TEC), fast oxygen exchange kinetics, and high chemical stability. Herein, Fe-doped Nd 0.8 Sr 1.2 Ni 1-x Fe x O 4±δ (x = 0, 0.15, 0.3, 0.45, NSNF) oxygen electrodes with fast oxygen reduction/evolution reactions (ORR/OER) kinetics are reported. The optimal composition of NSNF is found to be NSNF45 (x equals to 0.45) and the best ratio of NSNF45 to GDC is 6:4 by the mass ratio, delivering a low polarization resistance of 0.067 Ω cm2 at 800 °C. The RSOC with Co-free NSNF45-GDC (6:4) composite oxygen electrode achieves a high peak power density of 1.33 W cm−2 and a favorable electrolysis current density of 1.39 A cm−2 at 1.32 V with 50% steam concentration at 800 °C. Additionally, the reversible cycling between fuel cell and electrolysis modes at 700 °C and the thermal cycling between 700 °C and 300 °C show excellent stability over four hundred hours. The results indicate that composite NSNF45-GDC can be utilized as a promising oxygen electrode material for RSOCs. • A series of Nd 0.8 Sr 1.2 Ni 1-x Fe x O 4±δ are synthesized and evaluated. • The optimal NSNF45-GDC composite shows a R p of 0.067 Ω cm2 at 800 °C. • The cell show good electrochemical performance in both FC and EC modes. • High stability is demonstrated after the reversible cycling and thermal cycling test. [ABSTRACT FROM AUTHOR]

M‐N‐C single‐atom catalysts (SACs) are promising electrode materials for many electro‐reduction reactions. However, their stability is far from practical applications, and their deactivation mechanism has been rarely investigated. Herein, we demonstrate the structural degradation of M‐N‐C (M=Co, Ni, and Fe) at industrial‐grade current density for long‐term electro‐reduction. Both M‐N and N‐C bonds are broken, resulting in the gradual hydrogenation and dissolution of N in the form of ammonia. The residual M is finally converted to M‐containing core–shell nanoparticles after sequential dissolution, redeposition, and electro‐reduction. The destruction of the M‐N‐C structure and the formation of nanoparticles greatly affect the electrocatalytic performance. Our work highlights the structural degradation and deactivation mechanism of M‐N‐C‐type SACs under strong reductive conditions and provides useful information for inspiring researchers to develop new strategies to improve the electrocatalytic stability of similar types of materials. [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]

Stimulated by the increasing interest in ion adsorption effects on electrocatalytic reactions and by recent more detailed reports on the potential dependent adlayer structures formed on Ru(0001) in pure HClO4 and H2SO4 electrolytes, we revisited the oxygen reduction reaction (ORR) on structurally well‐defined Ru(0001) single crystal surfaces prepared under ultrahigh vacuum conditions. We demonstrate that the complex, potential‐dependent activity both for the ORR and for H2O2 formation is closely related to potential‐dependent changes in the composition and structure of the adlayer. Our results demonstrate the enormous effects adsorbed species can have on the ORR reaction characteristics, either by surface blocking, e. g., by (co‐)adsorbed bisulfate species, or by participation in the reaction, e. g., by *H transfer from adsorbed H or OH to O2. The comparison with results obtained on polycrystalline Ru, which differ significantly from Ru(0001) data, furthermore underlines the importance of using structurally well‐defined surfaces as a reference system for future theoretical studies. [ABSTRACT FROM AUTHOR]

Common half-cell measurements deliver oxygen reduction activities linked to the chosen scan rate, limiting their value for fundamental and comparative studies on platinum. Here we show a deconvolution of the intrinsic kinetics from the effect of surface oxygen on platinum. We find an electronic effect of the surface oxygen, substantiate a Tafel slope of ~120 mV/decade, obtain an exchange current density of 13 ± 4 µA/cm2, and an activity of 7 mA/cm2 at 900 mV. Eventually, we broaden the scope of this analysis to the effects of surface rearrangement, alloying, and supported Pt nanoparticles, the latter providing insight into discrepancies between half-cell and fuel cell measurements. We find through computational methods that binding energies of intermediates would be weakened by the presence of highly coordinated oxygen atoms. Finally, we obtain a phenomenological rate equation for the oxygen reduction and evolution reaction, suggesting that both reactions follow a shared mechanism. Catalyzing the splitting and formation of oxygen on noble metal surfaces are key reactions developing materials for electrolysis. Here, authors show on platinum that the state of a surface oxidation process is a key descriptor for the kinetics. [ABSTRACT FROM AUTHOR]