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The 2D porous protonated NiSe/g-C 3 N 4 nanosheets are synthesized via a chemical-calcination-etching-acidification-hydrothermal method. The obtained 2D NiSe/g-C 3 N 4 nanosheets (NiSe/HCN-3) exhibit signally enhanced HER (∼1184.74 μmol g−1 h−1)/degradation (∼0.04645 min−1) than the monomer g-C 3 N 4 (∼150/5-folds), including a decent stability (average HER ∼1152.71 μmol g−1 h−1). It mainly attributes to the NiSe/g-C 3 N 4 interface owns appropriate potential gradient can promote the interface carrier driving to optimize efficiency, including increasing carrier transport, extending carrier lifetime, and reducing recombination, as well as the porous nanosheets and surface protonation obtain numerous active sites for decreasing overpotential and promoting electron solid/liquid interfacial diffusion. Additionally, the 2D porous nanosheets can improve the solar efficiency (multiple internal reflections) and shorten the carrier pathway. [Display omitted] • NiSe co-catalyst optimize carrier efficiency by appropriate Fermi level gradient. • Surface protonation increase active sites to promote electron interfacial diffusion. • Porous nanosheets increase active sites/solar efficiency and shorten carrier path. [ABSTRACT FROM AUTHOR]

Atomic isolated and dispersed single atom catalyst is ideal for high-performance industrial catalyst. However, the contribution from small amounts of nanoclusters coexisting with single atoms to the catalytic reaction activity is often neglected. In this work, a MXene-supported uniformly dispersed Pt single atoms and nanoclusters (Pt 1 +Pt n /MXene) were obtained by self-assembly through an impregnation method. The catalyst exhibits high electrochemical performance in the hydrogen evolution reaction with an overpotential of only 61.3 mV and a Tafel slope of 32.5 mV dec−1 at a current density of 10 mA cm−2 in an acidic environment. The XAFS analysis and further DFT calculation indicate that the synergistic effect between single atoms and nanoclusters can facilitate adsorption of H* and promote the HER reaction. This work provides an efficient method for integrating multiple active sites in noble metal catalysts. • Constructing Pt sites on MXene enables a strong synergism between nanoclusters and single atoms. • Pt 1 +Pt n /MXene possesses large numbers of highly active Ti–O–Pt interfacial sites. • Ti–O–Pt sites make Pt 1 +Pt n /MXene obtain an outstanding catalytic performance in HER. • Pt 1 +Pt n /MXene boosts the adsorption of H* and promotes the HER reaction process. [ABSTRACT FROM AUTHOR]

Developing an OER electrocatalyst that combines high performance with low cost represents a crucial challenge to address for the widespread adoption and implementation of PEM water electrolyzers. The Ru-based catalyst has garnered significant interest owing to its cost-effectiveness and high activity, positioning it as one of the prime contenders to replace Ir-based catalysts. Nevertheless, Ru-based catalysts are easily corrupted by oxidation at high potential, leading to poor catalyst durability. In this work, we used a simple method to synthesize an electrode material which was a carbon framework-supported coralline RuCo alloy catalyst on the CC surface. The porous and highly conductive carbon framework in RuCo@C/CC effectively anchors the RuCo alloy, preventing its aggregation and detachment from the CC. And the carbon framework also facilitates enhanced mass and charge transfer processes, thereby greatly improving catalytic performance. Additionally, charge transfer and redistribution occur within the RuCo alloy, thereby efficiently reducing the activation energy barrier (via the AEM mechanism) of the OER, consequently enhancing OER performance. Therefore, RuCo@C/CC exhibits outstanding performance in acidic OER, achieving a current density of 10 mA/cm2 at a remarkably low overpotential of 200 mV, significantly surpassing commercial RuO 2 (which requires 280 mV), owing to its exceptional OER kinetics, while also demonstrating exceptional stability in practical PEMWE test. This research introduces a convenient route for creating a highly efficient and durable alloy electrocatalyst, showcasing its promise for Proton Exchange Membrane Water Electrolysis. • Charge transfer and redistribution within RuCo reduce the OER energy barrier. • Role of C skeleton in preventing RuCo shedding and enhancing mass and charge transfer. • RuCo@C/CC shows a low overpotential of 200 mV at η 10 , surpassing commercial RuO 2. [ABSTRACT FROM AUTHOR]

The advancement of effective and robust catalysts that can replace the precious-metal-based benchmarks for electrocatalytic overall water splitting is a highly fashionable approach to exploring sustainable energy utilization and addressing environmental issues. Herein, we demonstrate a facile single-step fabrication of NiS-NiS 2 nanoparticles in situ grown on the layered porous sulfur-doped graphitic carbon nitride nanosheets (NiS-NiS 2 /SGCN) act as bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline medium. Further, an increasing the Ni precursor (fixed sulfur source) increases the formation of NiS-NiS 2 on the surface of SGCN (labeled as NS-1.0, NS-2.0, and NS-3.0). Structural and morphological studies such as PXRD, XPS, FTIR, HR-TEM, etc., revealed a uniform distribution of NiS/NiS 2 on the surface of S-g-C 3 N 4 nanosheets. The OER and HER activity of NiS-NiS 2 /SGCN nanohybrid were significantly enhanced by increasing the affinity of accessible surface-active edge sites, interfacial contact allows effective modification of electronic structure, high structural porosity, redox-active centers of Ni2+/Ni3+, and rich in sulfur vacancy. In addition, the enhancement of the exposure of the edge sites is improved by their attachment to a sulfur-doped g-C 3 N 4 framework. As a result, in the half-cell experiments, the NiS-NiS 2 /SGCN (NS-3.0) catalyst exhibited enhanced performance in both OER and HER, requiring an overpotential of 298 mV to reach 50 mA/cm2 for OER and −144 mV to reach 10 mA/cm2 for HER. Furthermore, the constructed electrolyzer using Ni-S 3.0 as the cathode and anode required a cell voltage of 1.66 V to yield 50 mA/cm2 in overall water splitting. This study may inspire the in-situ synthesis of different metal sulfides on SGCN to provide a unique interfacial approach for improving the performance of bifunctional non-precious electrocatalysts. NiS-NiS2/SGCN as Bifunctional Electrocatalysts for HER and OER in an alkaline medium. [Display omitted] • Single-step fabrication of NiS-NiS 2 grown insitu on sulfur-doped graphitic carbon nitride. • NiS-NiS 2 /SGCN/NF exhibited a low OER overpotential of 298 mV (at 50 mA/cm2). • NiS-NiS 2 /SGCN/NF showed a low HER overpotential of −144 mV (at 10 mA/cm2). • NiS-NiS 2 /SGCN/NF electrode acts as a bifunctional electrocatalyst in alkaline media. [ABSTRACT FROM AUTHOR]

N-doped WO3 anchored on porous carbon (N–WO3/PNC) was synthesized as an efficient oxygen reduction catalyst. The N doping reduced the overpotential of WO3 during oxygen reduction. N–WO3/PNC displayed a half-wave potential of 0.85 V. An N–WO3/PNC-based zinc–air battery displayed a high power density of 209.7 mW cm−2. [ABSTRACT FROM AUTHOR]

While cobalt-based oxides can function as OER catalysts under acidic conditions, challenges such as high overpotential and inadequate stability persist, demanding solutions to fulfill practical application demands. We utilized a rapid and efficient one-step molten salt method to synthesize LaMn-doped Co 3 O 4 supported on carbon cloth, with the aim of improving its OER activity and stability in acidic conditions. Subsequent characterization revealed that doping increased oxygen vacancies and lattice distortion within the spinel structure, while also altering the morphology of the catalyst surface, rendering it denser. In addition, the doping optimizes the electronic structure around cobalt, so that the electrons around oxygen are biased towards cobalt, which enhances the electrocatalytic activity of Co 3 O 4 and the stability of Co–O bonds. Ultimately, under 0.5 M H 2 SO 4 conditions, LaMn–Co 3 O 4 /CC exhibited superior OER activity and stability, displaying a lower overpotential of 370 mV at a current density of 10 mA cm−2 and maintaining stability for over 24 h, a notable enhancement compared to pure Co 3 O 4. • Rapid synthesis of LaMn-doped Co 3 O 4 particles by a one-step molten salt method. • Doping inhibits particle growth and markedly influences the material's microstructure. • The performance of co-doped sample was markedly improved in all prepared materials. • The synergy of the two metals improves the catalytic performance of the material. [ABSTRACT FROM AUTHOR]

The electrolysis of water is the key method for hydrogen production but the high overpotential necessitates electrocatalysts. Traditionally, Pt is used, but it is scarce and costly. Herein, MnCO 3 is unveiled as an electrocatalyst for the production of hydrogen. MnCO 3 is electrodeposited onto pencil graphite by chronoamperometric method and confirmed by XRD and vibrational spectroscopic studies. MnCO 3 electrodeposited for 15 min at 2 V demonstrates a good HER activity (overpotential of 123 mV to reach 10 mA cm−2) in 0.5 M H 2 SO 4 with a Tafel slope of 79 mV dec−1. In addition, MnCO 3 exhibited good stability during continuous operation (over 3000 cycles and 14 h). Though MnCO 3 requires higher overpotential than the benchmark catalyst (Pt/C) to reach 10 mA cm−2, it outperforms Pt/C at higher current density (≥75 mA cm−2) demonstrating that MnCO 3 could be used as an electrocatalyst to produce H 2 at a high rate from acidic medium. [Display omitted] • MnCO 3 is electrodeposited onto pencil graphite by chronoamperometry method. • MnCO 3 electrodeposited at 2 V demonstrates a good HER activity in 0.5 M H 2 SO 4. • MnCO 3 exhibits good stability (over 3000 cycles and 14 h of continuous operation). • MnCO 3 surpassed the performance of Pt/C at 100 and 200 mA cm−2 [ABSTRACT FROM AUTHOR]

In recent years, the electrocatalytic nitrogen reduction reaction (NRR) has attracted considerable attention as a promising method for ammonia synthesis. Currently, various diatomic catalysts (DACs) composed of metal and non-metal combinations have been studied and reported for the NRR. These catalysts have been proven the ability to lower the reaction overpotential and enhance its activity. Among them, DACs supported on two-dimensional nitride materials have been widely applied in the NRR. In this work, ten heteronuclear diatomic catalysts supported on nitrogen-doped graphene were constructed. The research results demonstrated that MoCrN 6 -G exhibited the best catalytic performance among these catalysts due to its lowest overpotential (0.45 V) and low desorption free energy (0.15 eV) of NH 3 , as well as a higher selectivity for NRR compared to the hydrogen evolution reaction. It is worth emphasizing that the d-band center (ε d) is considered as a descriptor for rapidly screening efficient NRR electrocatalysts, further guiding the rational design of catalysts. [Display omitted] • Construced ten stable nitrogen-doped graphene supported heteronuclear diatomic catalysts. • The MoCrN 6 -G catalyst exhibited the lowest overpotential (0.45 V) during the NRR. • NH 3 can easily dissociate from the MoCrN 6 -G catalyst surface due to a desorption free energy of only 0.15 eV. • The MoCrN 6 -G catalyst demonstrated inhibitory effects towards the HER and showed high thermodynamic stability. • The d-band center (ε d) can serve as a predictive descriptor for rapidly screening highly active NRR catalysts. [ABSTRACT FROM AUTHOR]

The activation of lattice oxygen oxidation mechanism (LOM) will endow iridium‐based electrocatalysts with desired acid‐available water oxidation activity, compared to the conventional adsorbate evolution mechanism (AEM). However, the inherent symmetric [IrO6] octahedra of commercial Ir‐based catalysts generally thermodynamically favor the AEM pathway contributing to the moderate water oxidation performance. Here, based on typical layered Ca2IrO4 (CIO) modeled materials, the d‐orbitals electron repulsion strategy is demonstrated, via constructing asymmetrically polarized Ir‒O‒Ru configuration in Ru‐CIO, to effectively activate the lattice oxygen participating in water oxidation process for decent oxygen‐related electrocatalytic activity. Specifically, a great increase of ≈700‐fold and ≈170‐fold in mass activity and turnover frequency, respectively, has been realized for the optimal Ru‐CIO electrocatalyst in an acid medium relative to the commercial IrO2 electrocatalysts, where a small overpotential of only 175 mV is required for achieving 10 mA cmgeo‒2. In situ X‐ray fine structure spectroscopies combined with in situ 18O‐ isotope‐labeled differential electrochemical mass spectrometry analyses reveal that desirable LOM has been boosted by the activated lattice oxygen and the flexible Ir(3+δ)+ active sites of asymmetric [IrO6] octahedra, which results in superior OER kinetics for Ir‐based oxide catalysts. [ABSTRACT FROM AUTHOR]

Perovskite oxides are promising catalysts for water oxidation. Herein, we constructed a Sr3CoFeWO9 triple perovskite with Co, Fe, and W atoms sharing octahedral positions. Thermally activated growth of an amorphous FeCoW oxyhydroxide layer on this perovskite pre-catalyst greatly enhanced the oxygen evolution reaction (OER) activities, reducing overpotential at 10 mA cm−2geo by 115 mV. This highlights the benefits of compositional design and structural reconstruction for efficient electrocatalytic materials. [ABSTRACT FROM AUTHOR]

Overall urea–water electrolysis has the potential to be employed in the purification of urea-containing wastewater and the production of hydrogen. However, the lack of cost-effective catalysts currently presents a significant obstacle to the further development of this technology. Through a simple template-directed selenium reaction in a novel type of highly active solution, an interface engineering strategy was designed to synthesize hollow CuSe nanocubes as an efficient bifunctional catalyst. The unique hollow CuSe nanocubes exhibit significant catalytic efficiency because of their larger electrolyte contact area and faster ion transport. In 1 M KOH with a 0.5 M urea electrolyte, CuSe/NF required an overpotential of 199 mV for HER and a potential of 1.38 V for UOR to achieve a current density of 10 mA cm−2. It can work stably for 24 h without significant degradation of activity at 10 mA cm−2, showing excellent durability and excellent stability. For overall urea–water electrolysis, it exhibits a remarkable activity with a low cell voltage of 1.61 V at 10 mA cm−2. Consequently, the design strategy of this unique hollow-structured CuSe provides a new insight to improve electrocatalytic performance and stability. [ABSTRACT FROM AUTHOR]

Electrocatalytic conversion of CO2 into formate is recognized an economically‐viable route to upgrade CO2, but requires high overpotential to realize the high selectivity owing to high energy barrier for driving the involved proton‐coupled electron transfer (PCET) processes and serious ignorance of the second PCET. Herein, we surmount the challenge through sequential regulation of the potential‐determining step (PDS) over Te‐doped Bi (TeBi) nanotips. Computational studies unravel the incorporation of Te heteroatoms alters the PDS from the first PCET to the second one by substantially lowering the formation barrier for *OCHO intermediate, and the high‐curvature nanotips induce enhanced electric field that can steer the formation of asymmetric *HCOOH. In this scenario, the thermodynamic barrier for *OCHO and *HCOOH can be sequentially decreased, thus enabling a high formate selectivity at low overpotential. Experimentally, distinct TeBi nanostructures are obtained via controlling Te content in the precursor and TeBi nanotips achieve >90 % of Faradaic efficiency for formate production over a comparatively positive potential window (−0.57 V to −1.08 V). The strong Bi−Te covalent bonds also afford a robust stability. In an optimized membrane electrode assembly device, the formate production rate at 3.2 V reaches 10.1 mmol h−1 cm−2, demonstrating great potential for practical application. [ABSTRACT FROM AUTHOR]

The reconstruction of local electronic states in Pt-O x is an effective strategy for balancing charge distribution and enhancing the intrinsic activity of noble metals. This study presents the use of highly porous and oxygen-rich activated bluecoke powders as a desirable carbon support, and regulates Pt-O x bonds by incorporating the Fe as transition metal, leading to the development of an efficient bluecoke-based electrocatalyst characterized (Fe/Pt–O@MKABC) by exceptionally low Pt loading. The loading amount of Pt in Fe/Pt–O@MKABC is only 0.98 wt%, which is less than the 5% reported for commercial Pt/C catalyst, yet its hydrogen evolution performance is comparable. The developed catalyst presents exciting catalytic ability with overpotential of only 17 mV at 10 mA/cm2, a high mass activity of 8.3 A/(cm2·mg pt) at 50 mV, a large turnover frequency of 8.29 H 2 /s, and outstanding durability with a mere increase of 5 mV over 10000 cycles in acidic electrolyte. Detailed spectroscopic analysis and theoretical calculation results demonstrate that the abundant oxygen on activated bluecoke powders provides an opportunity for the construction of Fe-O y and Pt-O x. The introduction of Fe leads to electron rearrangement in Fe/Pt–O@MKABC, promoting electron transfer and reducing the adsorption free energy of H*, and the interaction between Fe-O y and Pt-O x enhances the hydrogen evolution reaction (HER) performance. [Display omitted] • Utilizing highly porous and oxygen-rich activated bluecoke powders as defect carbon support. • The introduction of Fe optimizes the Pt-O x bonds and significantly reduces the Pt loading. • The loading amount of Pt in the developed Fe/Pt–O@MKABC electrocatalyst is only 0.98 wt%. • The interaction between Fe-O y and Pt-O x accelerates the Volmer-Heyrovsky process. [ABSTRACT FROM AUTHOR]

The electrocatalytic performance of a Fe65Co10Si12.5B12.5 Fe-based compounds toward alkaline hydrogen evolution reaction (HER) is enhanced by dealloying. The dealloying process produced a large number of nanosheets on the surface of NS-Fe65Co10Si12.5B12.5, which greatly increased the specific surface area of the electrode. When the dealloying time is 3 h, the overpotential of NS-Fe65Co10Si12.5B12.5 is only 175.1 mV at 1.0 M KOH and 10 mA cm−2, while under the same conditions, the overpotential of Fe65Co10Si12.5B12.5 is 215 mV, which is reduced. In addition, dealloying treated electrodes also show better HER performance than un-dealloying treated electrodes. With the increase in Co doping amount, the overpotential of the hydrogen evolution reaction decreases, and the hydrogen evolution activity is the best when the addition amount of Co is 10%. This work not only provides a basic understanding of the relationship between surface activity and the dealloying of HER catalysts, but also paves a new way for doping transition metal elements in Fe-based electrocatalysts working in alkaline media. [ABSTRACT FROM AUTHOR]

The accurate representation of lithium plating and aging phenomena has posed a persistent challenge within the battery research community. Empirical evidence underscores the pivotal role of cell structure in influencing aging behaviors and lithium plating within lithium‐ion batteries (LIBs). Available lithium‐ion plating models often falter in detailed description when integrating the structural intricacies. To address this challenge, this study proposes an innovative hierarchical model that intricately incorporates the layered rolling structure in cells. Notably, our model demonstrates a remarkable capacity to predict the non‐uniform distribution of current density and overpotential along the rolling direction of LIBs. Subsequently, we delve into an insightful exploration of the structural factors that influence lithium plating behavior, leveraging the foundation laid by our established model. Furthermore, we easily update the hierarchical model by considering aging factors. This aging model effectively anticipates capacity fatigue and lithium plating tendencies across individual layers of LIBs, all while maintaining computational efficiency. In light of our findings, this model yields novel perspectives on capacity fatigue dynamics and local lithium plating behaviors, offering a substantial advancement compared to existing models. This research paves the way for more efficient and tailored LIB design and operation, with broad implications for energy storage technologies. [ABSTRACT FROM AUTHOR]

Oxygen evolution reaction (OER) over perovskite oxides, upon undergoing a lattice oxygen oxidation mechanism, is strongly oxygen vacancy‐correlated as determined by the oxygen ion diffusivity. Despite substantial efforts having been devoted to tuning the oxygen vacancy concentration in perovskite oxides, the impact of the concomitant altering of oxygen vacancy ordering is often underestimated. In particular, the underlying mechanism of how the ordering and the concentration of oxygen vacancy affect the lattice OER, and how to well balance them still remain inadequately understood. Herein, a series of Sr1−xCaxCo0.5Fe0.5O3−δ with gradually increased oxygen vacancy concentration and ordering are synthesized. Theoretical calculations indicated that a higher oxygen vacancy concentration promoted the lattice oxygen migration, whereas a higher oxygen vacancy ordering impeded it. Particularly, Sr0.5Ca0.5Co0.5Fe0.5O3−δ with a relatively higher oxygen vacancy concentration and a lower ordering displayed the maximum oxygen diffusion rate and the optimal OER activity, affording a current density of 10 mA cm−2 at a quite low overpotential of 310.2 mV, together with a small Tafel slope of 55.87 mV dec−1. This study sheds light on the critical influence of oxygen vacancy configuration on the lattice OER, and paves a compromised avenue to screen and design advanced electrocatalysts for various electrochemical devices. [ABSTRACT FROM AUTHOR]

In this contribution, the design of a graphene-supported high-entropy single-atom catalyst (HESAC) composed of Fe, Co, Ni, and Ru metal atoms (FeCoNiRu-HESAC) is proposed. Negative formation energy and positive dissociation potentials indicate such materials' thermodynamic and electrochemical stability. Based on density functional theory (DFT) calculations, Co active sites lead to the overpotentials of 0.28 V RHE for oxygen evolution reaction (OER), 0.16 V RHE for hydrogen evolution reaction (HER), and 0.25 V RHE for CO 2 reduction reaction (CO 2 RR) towards CO formation. These surpass the activity of CoN 4 single-atom catalyst. More interestingly, the low CO 2 RR and HER overpotentials enable the FeCoNiRu-HESAC to produce syngas (CO + H 2). In addition, the Fe, Ni, and Ru sites simply serve as counterparts to modify the performance of Co active sites through non-bonding interactions. Besides, machine learning (ML) implies that, the valence electrons of intermediates as well as the d orbital electrons of metal sites are the most important parameters affecting the reaction intermediates' Gibbs free energy. According to these DFT and ML results, a strategy to design multifunctional HESACs electrocatalysts is developed. [Display omitted] • DFT calculations performed on multifunctional FeCoNiRu-HESAC species. • FeCoNiRu-HESAC surpassed the OER, HER, and CO 2 RR activities of SAC. • Fe, Ni, and Ru served as counterparts enhancing OER, CO 2 RR, and HER activity of Co. • Low HER- and CO 2 RR-overpotentials enabled the FeCoNiRu-HESAC to produce syngas. • ML implied valence e− of intermediates & d orbital e− of catalyst active site as the key parameters. [ABSTRACT FROM AUTHOR]

This research aims to produce a highly stable, effective, economical, and novel electro-active catalyst for the oxygen evolution reaction, a significant advancement in green energy. The potential impact of this research is inspiring, as it could pave the way for more efficient and cost-effective green energy solutions. In this study, a CoFe 2 O 4 /g-CN composite catalyst was synthesized via the hydrothermal method. The samples were studied using several analytical techniques to evaluate shape and structure. This study used g-CN ultra-thin nanosheets as carriers for CoFe 2 O 4 nanoparticles to increase their active area and thus enhance their electrocatalytic performance. CoFe 2 O 4 /g-CN exhibited an improved ECSA (electrochemical active surface area) of 1337.5 cm2 and a higher Cdl value of 53.5 mF/cm2, significantly superior to the pristine CoFe 2 O 4. In comparison with pristine CoFe 2 O 4 , CoFe 2 O 4 /g-CN composite required a considerably reduced overpotential (ղ) of 200 mV to accomplish a current density (j) (10 mA/cm2). CoFe 2 O 4 /g-CN composite exhibited high stability of 35 h and a comparatively low Tafel plot (39 mV/dec). Considering all of these characteristics, it is clear that the CoFe 2 O 4 /g-CN composite could be an excellent electrocatalyst for the OER process. [Display omitted] • CoFe 2 O 4 /g-CN composite was fabricated via hydrothermal techniques for OER. • CoFe 2 O 4 /g-CN composite has a greater electrocatalytic efficiency for OER. • The small overpotential (200 mV) is required to attain 10 mA/cm2 having a Tafel plot (39 mV/dec). • CoFe 2 O 4 /g-CN demonstrated remarkable stability of 35 h. [ABSTRACT FROM AUTHOR]

In this paper, macroporous high‐entropy spinel oxide (HESO) (Fe0.2Ni0.2Co0.2Mn0.2Zn0.2)3O4 monoliths were successfully fabricated via a sol–gel method followed by calcination. Appropriate polyacrylic acid and propylene oxide contents allow the formation of three‐dimensional co‐continuous xerogel monoliths, and the water/glycerol ratio controls the macropore size of monoliths. Subsequent calcination achieves the precipitation of HESO (Fe0.2Ni0.2Co0.2Mn0.2Zn0.2)3O4 with a singular phase and exceptional structural stability. The macroporous HESO (Fe0.2Ni0.2Co0.2Mn0.2Zn0.2)3O4 demonstrates remarkable performance in the oxygen evolution reaction (OER) with an overpotential of 333 mV at 100 mA cm−2 and a Tafel slope of 43.2 mV dec–1, surpassing that of RuO2 (391 mV) under identical conditions. Furthermore, the catalytic stability of the HESO catalyst remains superior even after 24 h of testing. This process offers a promising avenue for the development of macroporous high‐entropy oxide OER catalysts for overall water splitting. [ABSTRACT FROM AUTHOR]

Herein, a binary inorganic molten salt electrolyte based on lithium bis(fluorosulfonyl)imide (LiFSI) and potassium bis(fluorosulfonyl)imide (KFSI) is applied to Li–CO2 batteries that can operate under 80 °C. Benefiting from the intrinsic nonvolatility, electrochemical stability, raised ionic conductivity, sufficient solubility and safety, the molten electrolyte endows the Li–CO2 battery with a large discharge capacity of 4612 mA h g−1 and superior rate capability. The introduction of the Ru@Super P carbon cathode further optimizes the discharge capacity (9503 mA h g−1), overpotential (1.15 V), and rate capability. [ABSTRACT FROM AUTHOR]

The development of electricity‐driven oxygen evolution reaction (OER) is a potent solution for energy storage applications. In recent years, there is a surge in interest in designing transition metal‐based catalysts with stable linkages, presenting an efficient alternative to noble metal‐based electrocatalysts. Transition metal complexes linked by salen ligands garner considerable attention due to their capacity to chelate and stabilize metal ions. This work presents a novel approach by strategically incorporating the metal–salen core into a porous organic polymer (POP) backbone, thereby fabricating a highly effective electrocatalyst for oxygen evolution. The judicious selection of metal–salen active sites, coupled with the intramolecular free volume (IMFV) of the triptycene core and the high specific surface area of the salen–POPs, result in superior OER activity. By precisely tuning the structure through variation of the transition metal in the salen unit, deep insights are gained into their electrocatalytic behavior. Notably, the most efficient catalyst, Ni‐DHDA‐TAT, exhibits an impressively low overpotential (η10) of ≈ 270 mV at a current density of 10 mA cm−2 for OER (in 1 m KOH). Further, Ni‐DHDA‐TAT retains its activity even after 50 h of chronoamperometry and 1000 cyclic voltammetry cycles with negligible degradation in its initial performance. [ABSTRACT FROM AUTHOR]

Modern civilization has been highly suffering from energy crisis and environmental pollutions. These two burning issues are directly and indirectly created from fossil fuel consumption and uncontrolled industrialization. The above critical issue can be solved through the proper utilization of green energy sources where no greenhouse gases will be generated upon burning of such materials. Hydrogen is the most eligible candidate for this purpose. Among various methods of hydrogen generation, electrocatalytic process is one of the most efficient methods because of easy handling and high efficiency. In these aspects Co‐based nanomaterials are considered to be extremely significant as they can be utilized as efficient, recyclable and ideal catalytic system. In this article a series of Co‐based nano‐electrocatalysts has been discussed with proper structure‐property relationship and their medium dependency. Therefore, such type of stimulating summary on recently reported electrocatalysts and their activity may be helpful for scientists of the corresponding field as well as for broader research communities. This can be inspiration for materials researchers to fabricate active catalysts for the production of hydrogen gas in room temperature. [ABSTRACT FROM AUTHOR]

The study examines the oxygen evolution reaction (OER) electrocatalytic efficiency of various stainless‐steel mesh (SSM) sizes in electrolytic cells. Stainless steel is chosen due to its widespread availability and stability, making it an economically viable option. The primary objective of this investigation is to determine the optimal stainless‐steel mesh size among those currently widely available on the market. The classification of stainless‐steel mesh sizes as SS304 is confirmed by the minimal compositional variations observed across all mesh sizes through electron dispersive X‐ray (EDX) spectra and X‐ray fluorescence (XRF) analyses. Remarkably, CV experiments carried out at different scan rates indicate that SSM 200 has the maximum specific electrochemical surface area (ECSA). As a result, SSM 200 demonstrates superior performance in terms of current density response and shows the lowest overpotential in the alkaline medium compared to other stainless‐steel mesh sizes. Furthermore, the SSM 200 exhibits a low overpotential of 337 mV at a current density of 10 mA/cm2 and a Tafel slope of 62.2 mV/decade, surpassing the performance of several previously reported electrodes for the OER. Stability tests conducted under constant voltage further confirm the remarkable stability of SSM 200, making it an ideal anode for electrolytic cell applications. These findings emphasize the cost‐effectiveness and high stability of SSM 200, presenting intriguing possibilities for future research and advancements in this field. [ABSTRACT FROM AUTHOR]

The quest for sustainable and clean energy sources has intensified research on the Hydrogen Evolution Reaction (HER) in recent decades. In this study, we have presented a novel Ce‐doped TiO2 catalyst synthesized through the sol‐gel method, showcasing its potential as a superior electrocatalyst for HER in an acidic medium. Comprehensive characterization through X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Energy dispersive X‐ray (EDX), and Raman spectroscopy confirms the successful formation of the catalyst. Electrocatalytic performance evaluation, including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and Tafel analysis, demonstrates that GCE‐5wt.%CeTiO2 outperforms bare GCE, as well as Ce and TiO2‐based electrodes. Kinetic investigations reveal a Tafel slope of 105 mV dec−1, indicating the Volmer step as the rate‐determining step. The onset potential for HER at GCE‐5wt.%CeTiO2 is −0.16 V vs. RHE, close to the platinum electrode. Notably, the catalyst exhibits a low overpotential of 401 mV to achieve a current density of 10 mA cm−2 with an impressive 95 % Faradaic efficiency. Furthermore, the catalyst demonstrates outstanding durability, maintaining a negligible increase in overpotential during a 14‐hour chronoamperometry test. These results have far‐reaching implications for the development of cost‐effective and efficient electrocatalysts for hydrogen production. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) are promising materials for oxygen evolution reactions (OERs), a key component of water splitting to produce hydrogen and oxygen via water electrolysis. However, the performance of LDHs can be limited by their low surface area and poor accessibility of active sites. In this work, we synthesized highly exfoliated 2D NiAl‐LDHs by aqueous miscible solvent treatment method (AMOST) and compared its electrocatalytic efficiency with its analogue synthesised via slow urea hydrolysis. We demonstrate that the exfoliated 2D LDHs prepared by AMOST method have a higher surface area and more active sites than the crystalline LDHs obtained through urea hydrolysis, resulting in a superior OER activity and efficiency. The exfoliated 2D LDHs required a lower overpotential of 280 mV to reach a current density of 50 mA cm−2 and it also outperformed IrO2, a benchmark OER catalyst, in terms of overpotential and stability. We demonstrate that the physicochemical properties of nanosheets derived from NIAl‐LDH‐based materials are strongly influenced by the synthetic methodology, which affects the exfoliation degree, surface area and active site density. These factors are crucial for improving the OER catalytic performance of these materials, as shown by our results. [ABSTRACT FROM AUTHOR]

Searching for highly efficient bifunctional oxygen evolution reaction/oxygen reduction reaction (OER/ORR) electrocatalysts for sustainable and renewable clean energy is vital. However, these electrocatalyst designs remain cost-prohibitive for both experimental and computational studies. This paper systematically investigates 5d transition metal (5d TM) doped into graphitic carbon nitride (g-C 3 N 3) as potential bifunctional OER/ORR electrocatalysts by considering the defect charge states through the defect chemistry study. Our formation energies results show that 33 kinds of 5d TM doped g-C 3 N 3 have better stabilities in the different charge states. Among them, Ir N ×@C 54 N 53 (Ir occupation N), Ir N •@C 54 N 53 , Pt N ×@C 54 N 53 (Pt occupation N), and Ir i •@C 54 N 54 (Ir interstitial sites) exhibit lower overpotentials. They are great candidates for bifunctional OER/ORR electrocatalysts. This is because adjusting the charge states of 5d-TM@g-C 3 N 3 can tune the interaction strength of the oxygenated intermediates. Furthermore, machine learning shows that the charge transfer of TM atoms (Q e) and total magnetic moment (μ B0) are the two most essential descriptors for OER and ORR overpotential, respectively. The charged defect adjusting of the bifunctional OER/ORR activity would develop the potential electrocatalysts for energy conversion applications. [Display omitted] • Obtained 33 kinds of 5d TM-doped g-C 3 N 3 have better stabilities in the different charge states. • Ir N × @ C 54 N 53 , Ir N • @ C 54 N 53 , Pt N × @ C 54 N 53 and Ir int • @ C 54 N 54 meet the requirements of bifunctional ORR/OER electrocatalysts. • Control of the charge states can optimize the bifunctional OER/ORR activity of 5d transition metal-doped g-C 3 N 3. • The TM atoms' charge transfer and magnetic moment are the most effective descriptors for OER and ORR's overpotentials. [ABSTRACT FROM AUTHOR]

Water splitting is an important approach to hydrogen production. But the efficiency of the process is always controlled by the oxygen evolution reaction process. In this study, a three-dimensional nickel–molybdenum binary nanoarray microstructure electrocatalyst is successfully synthesized. It is grown uniformly on Ni foam using a hydrothermal method. Attributed to their unique nanostructure and controllable nature, the Ni-Mo-based nanoarray samples show superior reactivity and durability in oxygen evolution reactions. The series of Ni-Mo-based electrocatalysts presents a competitive overpotential of 296 mV at 10 mA·cm−2 for an OER in 1.0 M KOH, corresponding with a low Tafel slope of 121 mV dec−1. The three-dimensional nanostructure has a large double-layer capacitance and plenty of channels for ion transfer, which demonstrates more active sites and improved charge transmission. This study provides a valuable reference for the development of non-precious catalysts for water splitting. [ABSTRACT FROM AUTHOR]

Long‐term operation of proton exchange membrane water electrolysis (PEMWE) poses significant challenges due to the high potential and strong acidic environment associated with the oxygen evolution reaction (OER), leading to severe catalyst degradation. Here, ultrafine iridium–ruthenium nanowires (IrRu NWs) are developed through a facile process, which exhibits excellent activity and stability for acidic OER. The IrRu NWs achieve an overpotential of 243 mV at 10 mA cm−2, which is significantly lower than that of commercial IrO2 and pure Ir nanowires. Importantly, the IrRu NWs demonstrate 17.6% higher current density at 2 V in real PEMWE device than that of the commercial IrO2 and Pt/C catalysts at the anode and cathode, respectively. The PEMWE device with the IrRu NWs catalyst layers can be stably operated at 1.0 and 1.5 A cm−2 for more than 500 h with a degradation rate of only 28 µV h−1, which makes the IrRu NWs a promising catalyst toward PEMWE applications. [ABSTRACT FROM AUTHOR]

Densely packed IrOx‐ionomer agglomerates play a crucial role in the high mass transport resistance inside the anode catalyst layer (ACL), which in turn greatly affects the electrolysis performance at high current density. Therefore, agglomerate engineering for PEMWE is proposed in this work to enhance the oxygen transport process inside ACLs. Using self‐assembling nanotechnology, tightly packed primary aggregates are avoided and introduce the interconnected submicron pores and nanocavities into the catalyst‐ionomer agglomerate, confirmed by synchrotron radiation‐based nano‐CT, TEM, and BET. Such agglomerate engineering results in the enhancement of both dissolved oxygen and oxygen bubble transport inside the ACL confirmed by RDE tests and in‐situ bubble visualization. As a result, the mass transport overpotential is significantly reduced from 330 to 30 mV at 5 A cm−2 in PEMWE, optimized Ohmic resistance and catalyst utilization are also observed. Finally, high operating current density is achieved, i.e., 5 A cm−2 @2.04 V with Nafion 115 membrane and 7 A cm−2 @ 2.07 V with Nafion 212 membrane, under a low catalyst loading of 0.72 mgIr cm−2. This study proves the importance and feasibility of agglomerate engineering in further elevating the performance of PEMWE. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction to multi-carbon products is a promising approach for achieving carbon-neutral economies. However, the energy efficiency of these processes remains low, particularly at high current densities. Herein, we demonstrate that the low energy efficiencies are, in part, sometimes significantly, attributed to the high concentration overpotential resulting from the instability (i.e., flooding) of catalyst-layer during electrolysis. To tackle this challenge, we develop copper/gallium bimetallic catalysts with reduced activation energies for the formation of multi-carbon products. Consequently, the reduced activation overpotential allows us to achieve practical-relevant current densities for CO2 reduction at low cathodic potentials, ensuring good stability of the catalyst-layer and thereby minimizing the undesired concentration overpotential. The optimized bimetallic catalyst achieves over 50% cathodic energy efficiency for multi-carbon production at a high current density of over 1.0 A cm − 2 . Furthermore, we achieve current densities exceeding 2.0 A cm − 2 in a zero-gap membrane-electrode-assembly reactor, with a full-cell energy efficiency surpassing 30%. Electroreduction of CO2 to fuels and chemicals is promising but hindered by its low energy efficiency. Here, the authors develop Cu/Ga bimetallic catalysts with reduced activation energies to mitigate the high concentration overpotential, thereby achieving high energy efficiency for CO2 reduction. [ABSTRACT FROM AUTHOR]

Developing highly active and stable electrocatalysts is essential for the large‐scale production of hydrogen from alkaline water. In this work, Ag single atoms and nanoparticles co‐decorated Co hydro(oxy)oxide (Ag SAs&NPs@CoO(O)H) is synthesized by a facile one‐step approach. Notably, the overpotential of Ag SAs&NPs@CoO(O)H is 200 mV at current density of 50 mA cm−2 during oxygen evolution reaction (OER). Meanwhile, it can display the mass activity of 637.47 A g−1Ag under 300 mV, which is 212.49 times higher than that of commercial IrO2. Moreover, the assembled Pt/C // Ag SAs&NPs@CoO(O)H system only requires 1.9 V to reach an industrial current density of 1000 mA cm−2 in alkaline water electrolyzer and exhibits excellent stability at large current density of 1000 mA cm−2. Furthermore, in situ Raman spectroscopy analysis coupled with theoretical calculations reveals an novel active site switching mechanism is found on Ag SAs&NPs@CoO(O)H. Specifically, the O* preferentially generates on the Ag NPs and then switches toward the Co3+ site in CoO(O)H to produce OOH* and O2. Meanwhile, the Ag SAs in the lattice of CoO(O)H can exert an inhibitory force on the reconstruction process of CoOOH to Co(OH)2, resulting in excellent anti‐dissolution stability. [ABSTRACT FROM AUTHOR]

A ferrocene-modified COF, namely Ni-Tph-COF-Fc, was synthesized and applied in OER. Compared with Ni-Tph-COF-OH, Ni-Tph-COF-Fc shows improved performance with a current density of 99.6 mA cm−2, an overpotential of 450 mV, and a Tafel slope of 73.1 mV dec−1, which may be attributed to a synergy between introduced ferrocene and metalloporphyrin in the COFs. Moreover, the enhanced OER performance leads to an improved CO2RR performance with an FECO of 93.1%. This work represents an effective strategy to enhance the anodic OER performance and realize efficient CO2RR. [ABSTRACT FROM AUTHOR]

The efficient electrosynthesis of hydrogen peroxide (H2O2) via two‐electron oxygen reduction reaction (2e− ORR) in neutral media is undoubtedly a practical route, but the limited comprehension of electrocatalysts has hindered the system advancement. Herein, we present the design of model catalysts comprising mesoporous carbon spheres‐supported Pd nanoparticles for H2O2 electrosynthesis at near‐zero overpotential with approximately 95 % selectivity in a neutral electrolyte. Impressively, the optimized Pd/MCS‐8 electrocatalyst in a flow cell device achieves an exceptional H2O2 yield of 15.77 mol gcatalyst−1 h−1, generating a neutral H2O2 solution with an accumulated concentration of 6.43 wt %, a level sufficiently high for medical disinfection. Finite element simulation and experimental results suggest that mesoporous carbon carriers promote O2 enrichment and localized pH elevation, establishing a favorable microenvironment for 2e− ORR in neutral media. Density functional theory calculations reveal that the robust interaction between Pd nanoparticles and the carbon carriers optimized the adsorption of OOH* at the carbon edge, ensuring high active 2e− process. These findings offer new insights into carbon‐loaded electrocatalysts for efficient 2e− ORR in neutral media, emphasizing the role of carrier engineering in constructing favorable microenvironments and synergizing active sites. [ABSTRACT FROM AUTHOR]

Context: The capacities of V-Si72, V-C72, and V-Al36N36 nanocages to catalyze the ORR processes have been investigated. The acceptable pathways of ORR processes on V-Si72, V-C72, and V-Al36N36 nanocages have been examined by DSD-PBEPBE-D3/aug-cc-pVDZ, PW91PW91/aug-cc-pVDZ, and COSMO model in the gas phase and water. The ΔGreaction values of reaction steps of ORR pathways on V-Si72, V-C72, and V-Al36N36 nanocages are calculated. The Eadoption and Eformation of V-Si72, V-C72, and V-Al36N36 nanocages are negative values and these nanostructures are stable materials. The H2O has the lowest Eadsorption on V-Si72, V-C72, and V-Al36N36 nanocages. The *OH formation, creation of *OH-OH*, and formation of O* are rate-determining steps of ORR mechanisms. The overpotential values of ORR processes on V-Si72, V-C72, and V-Al36N36 nanocages are 0.41, 0.37, and 0.30 V, respectively. The V-Al36N36 nanocage have lower overpotential for ORR processes than V-Si72 and V-C72 nanocages by DSD-PBEPBE-D3/aug-cc-pVDZ, PW91PW91/aug-cc-pVDZ, and COSMO model in the gas phase and water. The V-Al36N36 nanocage have more negative ∆Greaction for reaction steps of ORR than V-Si72 and V-C72 nanocages. The V-Al36N36 nanocage with lower overpotential is proposed as an effective catalyst for ORR processes via studied pathways. Methods: The DSD-PBEPBE-D3/aug-cc-pVDZ method has been used to optimize and calculate the frequencies of V-Si72, V-C72, and V-Al36N36 nanocages in GAMESS software. The complexes of O, OH, OOH, and H2O with V-Si72, V-C72, and V-Al36N36 nanocages are optimized and frequencies are determined by the DSD-PBEPBE-D3/aug-cc-pVDZ method. The Gactivation and ∆Greaction of ORR pathways on V-Si72, V-C72, and V-Al36N36 nanocages are calculated by DSD-PBEPBE-D3/aug-cc-pVDZ, PW91PW91/aug-cc-pVDZ, and COSMO model in the gas phase and water. [ABSTRACT FROM AUTHOR]

Over the last decades, the transition metal dichalcogenide (TMD) materials have been intensively investigated for hydrogen evolution reaction (HER). Among many TMD catalysts, MoS2 and WS2 are the most efficient materials for HER application because of their advantages including earth abundance, facile synthesis, and high catalytic activities. Herein, a simple and scalable process is introduced which was employed to prepare the nanoflower (NF) heterostructure of MoS2 and WS2 (MoS2/WS2 NF). The superior catalytic activity of the synthesized MoS2/WS2 NF could be contributed by the unique properties of the heterostructure between WS2 and MoS2 materials. Low overpotential (251 mV) at a current density of 10 mA cm−2, small Tafel slope (61 mV dec−1), good conductivity, and superstability are the main properties of the prepared MoS2/WS2 NF. This work presents a new facile novel to prepare efficient catalysts which could be great candidates for HER and electrocatalytic application. [ABSTRACT FROM AUTHOR]

Hydrogen production from seawater remains challenging due to the deactivation of the hydrogen evolution reaction (HER) electrode under high current density. To overcome the activity-stability trade-offs in transition-metal sulfides, we propose a strategy to engineer sulfur migration by constructing a nickel-cobalt sulfides heterostructure with nitrogen-doped carbon shell encapsulation (CN@NiCoS) electrocatalyst. State-of-the-art ex situ/in situ characterizations and density functional theory calculations reveal the restructuring of the CN@NiCoS interface, clearly identifying dynamic sulfur migration. The NiCoS heterostructure stimulates sulfur migration by creating sulfur vacancies at the Ni3S2-Co9S8 heterointerface, while the migrated sulfur atoms are subsequently captured by the CN shell via strong C-S bond, preventing sulfide dissolution into alkaline electrolyte. Remarkably, the dynamically formed sulfur-doped CN shell and sulfur vacancies pairing sites significantly enhances HER activity by altering the d-band center near Fermi level, resulting in a low overpotential of 4.6 and 8 mV at 10 mA cm−2 in alkaline freshwater and seawater media, and long-term stability up to 1000 h. This work thus provides a guidance for the design of high-performance HER electrocatalyst by engineering interfacial atomic migration. Stable and efficient hydrogen production from seawater remains challenging. Here the authors engineer sulfur migration in NiCoS electrocatalyst via N-doped carbon encapsulation, generating S vacancies and S doped CN active sites at the interface that improves electrocatalytic hydrogen evolution activity and durability in both alkaline freshwater and seawater. [ABSTRACT FROM AUTHOR]

Precise regulation of the active site structure is an important means to enhance the activity and selectivity of catalysts in CO2 electroreduction. Here, we creatively introduce anionic groups, which can not only stabilize metal sites with strong coordination ability but also have rich interactions with protons at active sites to modify the electronic structure and proton transfer process of catalysts. This strategy helps to convert CO2 into fuel chemicals at low overpotentials. As a typical example, a composite catalyst, CuO/Cu−NSO4/CN, with highly dispersed Cu(II)−SO4 sites has been reported, in which CO2 electroreduction to formate occurs at a low overpotential with a high Faradaic efficiency (−0.5 V vs. RHE, FEformate=87.4 %). Pure HCOOH is produced with an energy conversion efficiency of 44.3 % at a cell voltage of 2.8 V. Theoretical modeling demonstrates that sulfate promotes CO2 transformation into a carboxyl intermediate followed by HCOOH generation, whose mechanism is significantly different from that of the traditional process via a formate intermediate for HCOOH production. [ABSTRACT FROM AUTHOR]

Refining synthesis strategies for metal–organic framework (MOF)-based catalysts to improve their performance and stability in an oxygen evolution reaction (OER) is a big challenge. In this study, a series of nanostructured electrocatalysts were synthesized through a solvothermal method by growing MOFs and metal–triazolates (METs) on nickel foam (NF) substrates (named MET-M/NF, M = Fe, Co, Cu), and these electrocatalysts could be used directly as OER self-supporting electrodes. Among these electrocatalysts, MET-Fe/NF exhibited the best OER performance, requiring only an overpotential of 122 mV at a current density of 10 mA cm−2 and showing remarkable stability over 15 h. The experimental results uncovered that MET-Fe/NF underwent an in situ structural reconstruction, resulting in the formation of numerous iron/nickel (oxy)hydroxides with high OER activity. Furthermore, in a two-electrode water-splitting setup, MET-Fe/NF only required 1.463 V to achieve a current density of 10 mA cm−2. Highlighting its potential for practical applications. This work provides insight into the design and development of efficient MOF-based OER catalysts. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting is an ideal alternative to obtain hydrogen, which is a renewable and clean source of energy with a high calorific value. Designing a highly stable and affordable catalyst is a critical need for achieving the desired electrocatalytic efficacy. Three-dimensional (3D) nanomaterials (NMs) have a hierarchical or interconnected network or framework-like structure with commendable mechanical stability. They possess large surface area and electroactive sites, which have garnered immense scientific interest in the past few years. Different 3D NMs that have been used for electrocatalysis of water are the central focus of this review. There are only a handful of reports discussing them in the literature, but none of them comprehensively cover various 3D NMs as water-splitting catalysts. In addition, the basic concepts of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), as well as various metrics affecting water splitting kinetics, have been highlighted in detail. In the end, hurdles in the design and commercialization of highly stable water-splitting catalysts and their possible remedies have been discussed along with. [Display omitted] • Electrochemical water splitting is a plausible approach for producing hydrogen. • 3D nanostructured electrocatalysts have enhanced the efficacy of water splitting. • Fabrication and electrocatalytic activity of 3D nanocatalysts have been focussed. • Various metrics affecting the water splitting kinetics have also been discussed. • Hurdles in design and commercialization of these catalysts have been highlighted. [ABSTRACT FROM AUTHOR]

The design of high‐entropy single‐atom catalysts (HESAC) with 5.2 times higher entropy compared to single‐atom catalysts (SAC) is proposed, by using four different metals (FeCoNiRu‐HESAC) for oxygen reduction reaction (ORR). Fe active sites with intermetallic distances of 6.1 Å exhibit a low ORR overpotential of 0.44 V, which originates from weakening the adsorption of OH intermediates. Based on density functional theory (DFT) findings, the FeCoNiRu‐HESAC with a nitrogen‐doped sample were synthesized. The atomic structures are confirmed with X‐ray photoelectron spectroscopy (XPS), X‐ray absorption (XAS), and scanning transmission electron microscopy (STEM). The predicted high catalytic activity is experimentally verified, finding that FeCoNiRu‐HESAC has overpotentials of 0.41 and 0.37 V with Tafel slopes of 101 and 210 mVdec−1 at the current density of 1 mA cm−2 and the kinetic current densities of 8.2 and 5.3 mA cm−2, respectively, in acidic and alkaline electrolytes. These results are comparable with Pt/C. The FeCoNiRu‐HESAC is used for Zinc–air battery applications with an open circuit potential of 1.39 V and power density of 0.16 W cm−2. Therefore, a strategy guided by DFT is provided for the rational design of HESAC which can be replaced with high‐cost Pt catalysts toward ORR and beyond. [ABSTRACT FROM AUTHOR]

Anion-regulated two-dimensional amorphous bi-metallic NiFe nitrides are fabricated by annealing controllable NiFe complexes in the rational deep eutectic solvents. Owing to its ultrathin nature, controllable electronic structure, and self-converted amorphous–crystalline reconstruction, the optimized 2D NiFe0.05–N–Cl0.5(NO3)0.5–CP shows an excellent OER activity with a small overpotential and long-term stability at 1.5 A cm−2. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate an interface on porous nickel foam (NN) between crystalline nickel sulfide and amorphous nickel sulfide (NNS/NNSx) adapting simple hydrothermal and facile electrodeposition processes, respectively. The developed electrocatalyst required a low overpotential of 15 mV to deliver a current density of 10 mA cm−2 and the interface intrinsically activates the electrocatalyst with an onset overpotential comparable to that of Pt in an alkaline hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

To eliminate climate gas emissions from aluminum electrolysis, modifying a cryolite-based electrolyte partly replacing Na with K reduces liquidus, allowing a process temperature of 800°C. This enables the use of various metallic alloys for oxygen-evolving inert anode technology. This alternative process requires a higher energy efficiency to compensate for an increased reaction voltage, which highlights the importance of evaluating the kinetics and overpotential on oxygen-evolving anodes. This study evaluates anodic overpotentials using steady-state polarization on platinum and three Ni-Fe-Cu-based alloy compositions in a KF-NaF-AlF3-Al2O3(sat.) electrolyte at 800°C. The polarization curve on the platinum anode reveals two linear Tafel regions, while Ni-Fe-Cu anodes exhibit a single Tafel region. Notably, Ni-Fe-Cu anodes treated with high-temperature air oxidation to develop a pre-formed oxide layer exhibit better electrocatalytic activity than untreated anodes of corresponding composition. The kinetic equations, based on a theoretical model for the proposed mechanism of the oxygen evolution reaction, are derived and utilized to simulate overpotential and current, taking into account surface coverage. This model accurately predicts the two experimentally observed Tafel regions on the platinum anode, indicating a two-step charge transfer-controlled mechanism. We illustrate that multiple Tafel slopes can be attributed to the potential-dependent surface coverage of an adsorbate and can be correlated with the particular rate-determining step. [ABSTRACT FROM AUTHOR]

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Electrocatalytic activities for the oxygen reduction reaction (ORR) of Au electrodes modified by as prepared and size selected (0.45–1.0, 0.22–0.45, and 0.1–0.22 µm) h-BN nanosheet (BNNS), which is an insulator, were examined in O2 saturated 0.5M H2SO4 solution. The overpotential was reduced by all the BNNS modifications, and the smaller the size, the smaller the overpotential for ORR, i.e., the larger the ORR activity, in this size range. The overpotential was reduced by as much as ∼330 mV compared to a bare Au electrode by modifying the Au surface by the BNNS of the smallest size range (0.1–0.22 µm). The overpotential at this electrode was only 80 mV more than that at the Pt electrode. Both the rotation disk electrode experiments with Koutecky–Levich analysis and rotating ring disk electrode measurements showed that more than 80% of oxygen is reduced to water via the four-electron process at this electrode. These results strongly suggest and theoretical density functional theory calculations support that the ORR active sites are located at the edges of BNNS islands adsorbed on Au(111). The decrease in size of BNNS islands results in an effective increase in the number of the catalytically active sites and, hence, in the increase in the catalytic activity of the BNNS/Au(111) system for ORR. [ABSTRACT FROM AUTHOR]

The energy crisis stems from increasing demand, diminishing fossil fuel reserves, and insufficient investment in renewable alternatives, posing a profound threat to global energy security and environmental sustainability. Fuel cells offer promise as a solution to the energy crisis and the integration of two-dimensional carbon materials in fuel cell catalysts holds potential for enhancing efficiency, reducing costs, and improving the overall sustainability of fuel cell technologies. The new two-dimensional carbon form tetra-penta-octagonal-graphene and its boron doped derivative have been examined in this report for its applicability in the electrocatalytic oxygen reduction reaction for generation of electricity. The most favorable site for the reaction in the pristine specimen and the most favorable boron doping site have been carefully determined based on adsorption energy and formation energy, respectively. Projected density of states confirms a low density of states for the active site in both specimens. Boron doping causes a significant charge transfer from the primed site. The analysis of the four electron pathways along with the dioxygen adsorption step in the acidic medium has been conducted to gain a deeper understanding of the process. In both systems, the formation of the *O intermediate is associated with the highest Gibbs free energy change. The performance of the pristine material in the process has been found to support monotonically exothermic reaction with an overpotential of 0.622 V whereas the boron doped specimen presents very small barrier for the dioxygen adsorption step followed by monotonically exothermic reaction steps with overpotential 0.549 V. • A new sp2 stable 2D carbon allotrope TPO-graphene shows electrocatalytic activity. • Active site has lowest partial density of states at Fermi level. • Steps of ORR in four-electron pathway in acidic medium are monotonically exothermic. • TPO-graphene has a overpotential of 0.622 V for the ORR process. • Boron doping creates ORR catalysis site with lowest partial density of states. • Boron doped TPO-graphene has a overpotential of 0.549 V for the ORR process. [ABSTRACT FROM AUTHOR]

Facile preparation of low-cost electrocatalysts for an efficient oxygen evolution reaction (OER) is significant but remains a big challenge. Herein, a novel and facile strategy for transforming intrinsic non-stoichiometric ultrathin Co5(O9.48H8.52)NO3 nanosheets into oxygen-vacancy enriched Co3O4/CoOOH heterostructure nanosheets for an efficient OER was developed. The as-synthesized Co3O4/CoOOH heterostructure nanosheets displayed excellent OER performances, showing an extremely low overpotential of 260 mV at a current density of 10 mA cm−2, a relatively small Tafel slope of 52 mV dec−1, and a long-term durability of at least 20 h. This work provides a new way for the production of oxygen vacancies on metal (oxy)hydroxide nanosheets through electric-field assisted in situ transformation of non-stoichiometric metal oxyhydroxide nanosheets. [ABSTRACT FROM AUTHOR]

An advance of highly efficient nanostructured electrocatalysts based on non-noble metals for water electrolysis and urea oxidation reaction (UOR) are of great significance for urea-enriched wastewater remediation and producing hydrogen. Herein, we report V x Ni 1-x O catalysts supported on three-dimensional Ni-foam scaffold for catalytic water and urea electrolysis. V x Ni 1-x O catalysts show rapid water and urea electrolysis due to enhanced electrochemical surface area (ECSA). Most important of all, the urea oxidation reaction has a lower potential of 1.418V vs RHE as compared to oxygen evolution reaction (1.684 V vs RHE) system to generate 100 mA/cm2. Additionally, a two-electrode cell for bi-functional water electrolysis generates 100 mA/cm2 at a potential of 2.10 V at 20 °C and just 1.86 V at 60 °C temperature due to regulated the adsorption/desorption of intermediates species, enhanced charge and mass transport, and easier desorption of oxygen molecules from the anode. The stability of V x Ni 1-x O catalyst was measured at 1000 mA/cm2 current density for up to 17 h. • Doping energy strategy to design a vertical V x Ni 1-x O nanosheets for water and urea electrolysis. • Overpotential of 454 mV for OER and 271 mV for HER at 100 mA/cm2. • Maximum current of 1000 mA/cm2 is achieved at a cell potential of 2.3 V. • V 0.1 Ni 0.9 O catalyst shows he stability for 17 h at 1000 mA/cm2. • Urea electrolysis system has a lower cell potential of 1.418V at 100 mA/cm2. [ABSTRACT FROM AUTHOR]

A systematic investigation of the electrochemical iron nitride synthesis in a LiCl/KCl salt melt at 723 K shows an optimum of ϵ -Fe 3 N 1 + x formation in the range of 2.2 to 2.3 V and for γ ′ -Fe 4 N between 2.4 and 2.5 V enabling the control of the desired iron nitride phase by setting the supplied terminal voltage. The product formation of iron nitrides starts when the electrochemical window is reached, which could be verified by linear sweep voltammetry. Hence, a maximum of nitrogen content in the formed iron nitride phases is observed for 2.27 V. During elongated synthesis periods, convection emerges as the predominant transport mechanism hindering an accelerated reaction rate with higher overpotential applied. Real-time analysis of the background current allows conclusions about the remaining nitride concentration. Additionally, there is concurrent iron nitride formation at the electrode surface through nitride adsorption and autonucleation-induced precipitation of iron and nitride ions. The analysis of the amount of sediment in comparison to the layer thickness of the nitrided working electrode suggests that the autonucleation mechanism dominates over the adsorption mechanism with increasing overpotential and can be further enhanced by this feature. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) process involves the magnetic reversal of oxygen-containing intermediates, and the influence of defect structures on the magnetic behavior of catalysts might play a crucial role in this process. There is scarce research on the intrinsic relationship among defects, magnetism and catalysis. Herein, cation vacancy β -Ni(OH) 2 nanosheets were successfully prepared through alkaline selective etching. To further analyze their spin-magnetic behavior, we found that the presence of defects caused the transformation of Ni(OH) 2 from antiferromagnetic to ferromagnetic. Furthermore, to further elucidate their intrinsic spin-magnetic effects, it was observed that the initially antiferromagnetic β -Ni(OH) 2 exhibited almost no spin-magnetic response upon the introduction of a magnetic field, with the overpotential almost unchanged. Conversely, introducing defect structures showed a noticeable spin-magnetic effect, reducing the overpotential by 20 mV at 20 mA cm−2. The combination of defects and magnetic fields provides new principles for developing high-performance catalysts and understanding catalytic mechanisms at the spin-electronic level. • Ni 1-x Vac x (OH) 2 was prepared to investigate the spin-magnetic behavior of defect. • The defects of Ni(OH) 2 led to transformation from antiferromagnetic to ferromagnetic. • The spin-magnetic effect can reduce the overpotential by 20 mV at 20 mA cm−2. [ABSTRACT FROM AUTHOR]