Bifunctional Catalysts Research Articles

CoFe2O4 with the In-Situ Formed Oxygen Vacancies and Co Particles as an Efficient Bifunctional Catalyst for Rechargeable Zinc-Air Batteries.

Rechargeable zinc-air batteries (RZABs) are considered as one of the most promising clean energy device due to their abundant resources, low cost and environmental friendliness. However, their energy efficiency and cycle life are far from satisfactory due to the poor activity and stability of bi-functional electrocatalyst in air cathode. In this work, an efficient bi-functional catalyst (rGO-CoFe2O4/Co) was derived from its precursor (rGO-CoFe2O4) through a simple annealing process. Electrochemical measurements prove that rGO-CoFe2O4/Co with the in-situ formed Co nano particles and rich oxygen vacancies appears excellent oxygen reduction reaction and oxygen evolution reaction catalytic activity compared to its counterpart. Its half-wave potential is 0.81 V (vs RHE) and the OER overpotential is only 310 mV (vs RHE). In addition, rechargeable zinc-air batteries assembled with rGO-CoFe2O4/Co show the highest peak power density (128.9 mW cm-2) and cycling stability compared to rGO-CoFe2O4 and commercial Pt/C-RuO2 catalysts. This work provides a simple strategy for the design of advanced bifunctional catalysts.

Facile Synthesis of Metal/Carbide Hybrid toward Overall Water Splitting

The development of cost-effective and high-performance bifunctional catalysts for overall water splitting is crucial for achieving sustainable clean energy. In this study, a metal/carbide hybrid (NiFeMo/NiFeMoCx) was prepared through fast and facile cathodic plasma electrolytic deposition. Due to the synergistic effect between the metal and carbide, NiFeMo/NiFeMoCx exhibited high activity in both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), with overpotentials of 230 mV and 60 mV at 10 mA cm−2, respectively. In addition, robust stability was demonstrated during the overall water splitting (1.52 V at 10 mA cm−2, with little degradation after 18 h of catalysis). This work provides a useful strategy for designing advanced water splitting catalysts for real application.

Metal‐Organic Framework Materials as Bifunctional Electrocatalyst for Rechargeable Zn‐Air Batteries

AbstractRechargeable Zn‐air batteries offer the advantages of environmental friendliness, safety, low prices and high energy density, and are highly valued. However, the major challenge faced by rechargeable Zn‐air batteries nowadays is the low energy efficiency due to the slow reaction kinetics of electrocatalyst at the air cathode. Bifunctional catalysts are key to the development of Zn‐air batteries by improving their overall performance and long‐term cycling stability. Metal‐organic framework (MOF) materials have shown great benefits as oxygen electrocatalysts in promoting oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). This paper reviews the recent advances of three kinds of MOF materials as bifunctional catalysts for rechargeable Zn‐air batteries. Additionally, this paper also discusses the synthetic design strategy of MOF composite derivatives, and concludes by suggesting the application of MOF materials in the field of rechargeable Zn‐air batteries.

Boosting the electrocatalytic performance of Co2P/Ni3S2 heterostructure for efficient water splitting

The development of a catalyst exhibiting outstanding catalytic activity and robust stability for both the oxygen evolution reaction and hydrogen evolution reaction in alkaline media represents a substantial challenge. In this work, a NF/Ni@NiCoSP heterostructure bifunctional catalyst was developed via a sequent process of electrodeposition-hydrothermal-low temperature thermal pyrolysis sulphuration/phosphorization. The physical characterizations reveal that the as-prepared sample of NF/Ni@NiCoSP exhibits a porous nano-needles array structure and consists of both Ni3S2 and Co2P phases with considerable boundaries. As a consequence, the NF/Ni@NiCoSP presents an ultralow overpotential of 47 mV and 260 mV at 10 mA cm−2 for hydrogen evolution reaction and oxygen evolution reaction, respectively. When assembled to a two-electrode system, it only requires 1.53 V to reach 10 mA cm−2, which surpasses the commercial RuO2‖Pt/C (1.61 V). The methanol oxidation reaction probing experiment suggests the easy desorption of ∗OH from active sites due to the decreased binding strength between ∗OH and the catalyst, thus optimizing the kinetics condition. Moreover, the in-situ Raman spectra reveal that NiOOH and CoOOH serve as active sites for OER while the metal sites for HER. Therefore, this work introduces a feasible strategy to design cost-effective and robust catalysts with excellent catalytic properties, thereby paving the way for water splitting.

Bifunctional Lewis Base-Catalyzed (3 + 2) Cycloadditions of Pyrazolone-Derived MBH Carbonates with Arynes.

The (3 + 2) cycloaddition of arynes with allylic ylides remains a formidable challenge because both intermediates are highly reactive and prone to spontaneous quenching. Here, we report a (3 + 2) cycloaddition of pyrazolone MBH carbonates with arynes, enabling the efficient synthesis of diverse indene-fused spiropyrazolones. The key is employing a new bifunctional Lewis base catalyst to facilitate the cycloaddition of in situ generated allylic pyridinium ylides with arynes.

P-Block-metal bismuth embedded in N/P co-doped carbon nanorods for kinetics-enhanced rechargeable lithium-oxygen batteries

Rechargeable lithium-oxygen batteries (LOBs) are considered one of the most promising electrochemical energy storage devices due to their extremely high theoretical energy density. However, the slow redox kinetics of the oxygen cathode leads to low coulombic efficiency and poor cycling performance, which limits the development of high-performance LOBs. Herein, Bi@NPC heterostructure nanorods are designed with the assistance of p-block metal Bi and successfully synthesized as bifunctional cathode catalysts for LOBs. Experimental and theoretical calculations show that Bi@NPC electrode can significantly reduce overpotential during discharge/charge processes due to the easily tunable localized p-orbitals and resulting versatile electronic structures. Benefiting from p-orbital electrons regulation of Bi atoms, the Bi@NPC electrode exhibited superior specific capacity over 11852.6 mAh g−1, outstanding rate capabilities, and ultralong cycle stability over 83 cycles at 200 mA g−1 with the fixed capacity of 500 mAh g−1. This work reveals an efficient pathway to synthesize p-block metal-based catalysts for high-performance LOBs.

Constructing Hydrangea-Like Iron-Cobalt Phosphides via Boron-Assisted Strategy as an Efficient Catalyst for Water Splitting at High Current Density.

Finding suitable bifunctional catalysts for industrial hydrogen production is the key to fully building a hydrogen energy society. In this study, we present a novel approach to modifying the surface morphology of electrodeposited cobalt phosphide (CoP). Specifically, we have developed a method to create a hydrangea-like structure of bimetallic cobalt-iron phosphide (B-CoFeP@CoP) through ion-exchange and NaBH4-assisted strategies. This catalyst exhibited excellent bifunctional catalytic capability at high current densities, achieving a current density of 500 mA cm-2 at a small overpotential (387 mV for OER and 252 mV for HER). When assembled into an OWS electrolyzer, this catalyst showed a fairly low cell voltage (≈1.88 V) at 500 mA cm-2 current density., Furthermore, B-CoFeP@CoP shows ceaseless durability over 120 h in both freshwater and seawater with almost no change in the cell voltage. A combined experimental and theoretical study identified that the unique hydrangea-like structure provided a larger electrochemically active surface area and more effective active sites. Further analysis indicates that during the OER process, phosphides ensure that bimetallic active sites adsorb more OOH * intermediates and further DFT calculations showed that B-Fe2P and B-Co2P acted as active centers for dissociation of H2O and desorption of H2, respectively, to synergistically catalyze the HER process.

Ru-WOX-doped biochar for selective ethylene glycol production from cellulose hydrogenolysis: Unravelling the role of WOX in adjusting acid-metal balance

Ru-WOX composites are usually bi-functional catalysts for cellulose hydrogenolysis, but the proportion/synergism of Ru (metal) and WOX (acidity) are mismatched/unclear, this leads to low ethylene glycol (EG) yield. In this work, we doped Ru‑WOX on low-costed biochar for cellulose hydrogenolysis. The acid-metal balance was adjusted by change the WOX load, and our results show that the activity and EG yield have the order of Ru-30WOX-C > Ru-40WOX-C > Ru-20WOX-C > Ru-10WOX-C, and it is interesting found that a linear relationship between acid/metal ratio and EG yield. Under the optimum conditions (240 °C, 3 MPa and 3 h), Ru-30WOX-C catalyst can achieve 100% cellulose conversion and 61.3% EG yield. 30%WOX facilitates Ru dispersion/reduction, and provides rich acid sites, accompanied by a large number of acid centers (oxygen vacancies), this more easily adsorbed cellulose monomer and activated glucose to glycolaldehyde, and benefit to EG productive. This work provides a guidance to design new bio-functional catalysts for biomass conversion.

Single-Atom Doped Fullerene (MN4-C54) as Bifunctional Catalysts for the Oxygen Reduction and Oxygen Evolution Reactions.

Development of high-performance oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts is crucial to realizing the electrolytic water cycle. C60 is an ideal substrate material for single atom catalysts (SACs) due to its unique electron-withdrawing properties and spherical structure. In this work, we screened for a novel single-atom catalyst based on C60, which anchored transition metal atoms in the C60 molecule by coordination with N atoms. Through first-principles calculations, we evaluated the stability and activity of MN4-C54 (M = Fe, Co, Ni, Cu, Rh, Ru, Pd, Ag, Pt, Ir, Au). The results indicate that CuN4-C54, which is based only on earth-abundant elements, exhibited low overpotentials of 0.46 and 0.47 V for the OER and ORR, respectively, and was considered a promising bifunctional catalyst, showing better performance than the noble-metal ones. In addition, according to the linear relationship of intermediates, we established volcano plots to describe the activity trends of the OER and ORR on MN4-C54. Finally, d-band center and crystal orbital Hamiltonian populations methods were used to explain the catalytic origin. Suitable d-band centers lead to moderate adsorption strength, further leading to good catalytic performances.

PROSPECTS FOR USING A COBALT CATALYST FOR FISHER-TROPSCH SYNTHESIS BASED ON SYNTHETIC SILICA ALUMINA

The possibility of the use of commercially available silica-alumina hydrate Siral-40, containing 40 wt.% of SiO2, in the composition of a composite cobalt Fischer–Tropsch synthesis (FTS) catalyst was studied. The use of silica aluminas may become a new promising direction in the development of catalysts for a shortened technological chain based on the use of bifunctional catalysts that make it possible to eliminate the hydroprocessing stage. In addition, such catalysts can be useful for expanding the range of products obtained, including those unconventional for single-reactor Fischer–Tropsch synthesis. The initial silica alumina powder was pretreated in air flow at different temperatures to adjust the concentration of acid cites on its surface. The initial and calcined powders were studied using X-ray diffraction analysis, IR spectroscopy and sorption methods. The catalysts were investigated by diffraction and sorption methods. It has been shown that an increase in the calcination temperature of the initial Siral-40 powder leads to a decrease in the specific surface area and pore volume of catalysts based on it, with temperatures above 900 °C having the greatest effect. The synthesized catalysts were active in FTS, and the composition of the obtained C5+ hydrocarbons depended more on the properties of the Siral-40 powder than the catalytic performance. The composition of C5+ hydrocarbons, obtained in the presence of all investigated catalysts contained at least 60% of diesel fraction and more than 30% of wide base oil fraction. Thus, synthetic amorphous silica aluminas are a promising component for new Fischer–Tropsch synthesis catalysts, which make it possible to obtain a wide range of products without the use of a deep hydroprocessing stage in the technological chain. For citation: Sineva L.V., Asalieva E.Yu., Gryaznov K.O., Mordkovich V.Z. Prospects for using a cobalt catalyst for Fisher-Tropsch synthesis based on synthetic silica alumina. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 10. P. 88-98. DOI: 10.6060/ivkkt.20246710.7y.

Polyethylene glycol promoted Cs/Zr-SiO2 bifunctional catalyst for aldol condensation of methyl propionate and formaldehyde to methyl methacrylate

The production of methyl methacrylate (MMA) via one-step gaseous aldol condensation of methyl propionate (MP) and formaldehyde (FA) has received wide attention. Herein, series of polyethylene glycol (PEG) promoted Cs-Zr/SiO2 catalysts were developed and characterized by XRD, FT-IR, HR-TEM, BET, NH3–/CO2-TPD and Py-IR etc. The dispersion of active acid and base sites and their balance in catalyst could be significantly improved with the addition of PEG, which facilitated the activation of reactants and conversion towards product MMA. Furthermore, the relationship between the acid-base properties and catalytic performance was revealed, the acid and base sites were responsible for the decomposition of trioxane, which was used as the source of FA, and transformation of MP, respectively. The in-situ DRIFTS experiments unraveled two catalytic pathways through the synergistic effects between the acid and base sites during the aldol condensation of MP with FA to MMA. Kinetic studies revealed that the activation energy of this aldol condensation on the optimal catalyst is 97.9 kJ/mol, with the reaction order of 0.98 and 1.18 corresponding to MP and FA. Deactivation behavior studies demonstrated that the decrease of catalytic activity as a function of time-on-stream was resulting from the deposition of predominant amorphous carbon instead of the loss of active components.

Asymmetric Photoinduced Excited-State Nazarov Reaction.

We report herein the first asymmetric photoinduced excited-state Nazarov reaction of non-aromatic dicyclic divinyl ketones by using hydrogen-bonding catalysis. The enantioselectivity of photoinduced electrocyclization is highly dependent on the structural features of the substrate and its interaction with chiral catalysts. For the simple dicyclic divinyl ketone substrates, there is no discernible selectivity of the hydrogen bond coordination between the thiourea and carbonyl groups of the substrates in the ground state. However, we found that the direction of the electrocyclization was well controlled in each coordination model and the N,N'-dimethylamine motif acts as a base in the regioselective deprotonation process, which leads to the formation of two stereoisomers with high enantioselectivity. Photolysis of dicyclic divinyl ketones bearing a 1,3-dioxolane motif in the presence of bifunctional hybrid peptide-thiourea chiral catalysts gave the tricyclic cis-hydrofluorenones with good enantioselectivity. Mechanistic and DFT studies suggested that the amide and thiourea groups in the bifunctional chiral catalysts play a key role as H-bond donors, which coordinate with both the carbonyl group and the 1,3-dioxolane motif to provide a more favorable chiral species, and control the direction of the electrocyclization. Due to the presence of the rigid 1,3-dioxolane ring, the deprotonation/protonation process occurs regiospecifically with high driving force. This photo-electrocyclization is mild (room temperature and neutral solution), which results a broad reaction scope and functional group tolerance and demonstrates its synthetic potential in organic synthesis.

Modified Biochar Materials From Eucalyptus globulus Wood as Efficient CO2 Adsorbents and Recyclable Catalysts

AbstractHighly porous carbon materials derived from renewable resources constitute a promising and sustainable strategy regarding the enhancement of CO2 capture technologies. In this work, the valorization of Eucalyptus globulus wood, a forest invasive species present in European forests, is performed through its transformation in biochar. The deposition of nitrogen and different metals (aluminum, copper and chromium) onto biochar is performed, using the magnetron sputtering as a pioneering technique, to produce coated biochar nanoparticles with improved properties. The resultant modified biochar particles maintain a highly porous structure and present a remarkable CO2 adsorption capacity (up to 4.80 mmol g−1 for N@BC), which is attributed to the synergy of their large total surface area (527 m2 g−1) and microporosity (pore diameter = 21 Å), with a high content of nitrogen and oxygen heteroatom moieties (40.4% N, 11.4% O). Their application as heterogeneous bifunctional catalysts in CO2 cycloaddition to epichlorohydrin is performed, in the absence of any solvent or co‐catalyst, under moderate conditions (20 bar CO2, 120 °C), leading to good conversions (up to 58% conversion) and excellent selectivity for cyclic carbonates. Cu‐coated biochar is shown to be more stable than non‐modified material, being recycled and reused along 4 consecutive runs without loss of catalytic activity or selectivity.

Chemical coupling engineered exceptional overall water splitting of autogenic NiS/FeS/NiFeOOH heterostructure

The commercial application of hydrogen production is heavily subjected to the expensive and complex fabrication of required bifunctional catalysts integrated with good oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) activity. Herein, a simple one-spot hydrothermal technique is advocated to simplify the synthesis of NiS/FeS/NiFeOOH heterostructure (denoted as NiFeS) and achieve exceptional bifunctional electrocatalyst for water splitting. Such NiFeS heterostructure reveals multi-synergistic heterointerfaces with chemical coupling to provide more accessible active sites, regulate electronic structure of the active center and enhance interfacial charge transfer, enabling a significant contribution in improving the catalysis. Therefore, the OER overpotential of NiFeS catalyst is only 249 mV to supply 100 mA cm−2 current density, and the overpotential for HER reaches to 153 mV at 10 mA cm−2. When constructed into a lab-made electrode system, it confirms a remarkable cell voltage of only 1.51 V at 10 mA cm−2 for water splitting, along with an exceptional durability up to 100 h at 100 mA cm−2. This study gives a novel insight into heterostructure engineering for the construction of bifunctional electrocatalysts.

Efficient Electrocatalytic Oxidation of Glycerol to Formate Coupled with Nitrate Reduction over Cu-Doped NiCo Alloy Supported on Nickel Foam.

Electrooxidation of biomass-derived glycerol which is regarded as a main byproduct of industrial biodiesel production, is an innovative strategy to produce value-added chemicals, but currently showcases slow kinetics, limited Faraday efficiency, and unclear catalytic mechanism. Herein, we report high-efficiency electrooxidation of glycerol into formate via a Cu doped NiCo alloy catalyst supported on nickel foam (Cu-NiCo/NF) in a coupled system paired with nitrate reduction. The designed Cu-NiCo/NF delivers only 1.23 V vs. RHE at 10 mA cm-2, and a record Faraday efficiency of formate of 93.8 %. The superior performance is ascribed to the rapid generation of NiIII-OOH and CoIII-OOH species and favorable coupling of surface *O with reactive intermediates. Using Cu-NiCo/NF as a bifunctional catalyst, the coupled system synchronously produces NH3 and formate, showing 290 mV lower than the coupling of hydrogen evolution reaction, together with excellent long-term stability for up to 144 h. This work lays out new guidelines and reliable strategies from catalyst design to system coupling for biomass-derived electrochemical refinery.

Efficient, chlorine-free, and durable alkaline seawater electrolysis enabled by MOF-derived nanocatalysts

The development of cost-effective, scalable, and non-precious based bifunctional catalysts that can efficiently catalyze the sluggish oxygen and hydrogen evolution reactions (OER and HER) in the highly corrosive seawater medium is challenging, yet vital to realize a practical seawater electrolyzer. In this work, we demonstrate a nickel-exchanged zeolitic imidazolate framework (Ni@ZIF67)-derived nickel-cobalt-cobalt oxide nanoparticles embedded amorphous carbon (Ni–Co–CoO@C) nanocomposite as an efficient, chloride-resistant, and stable bifunctional catalyst in alkaline seawater. The OER and HER activities are meticulously characterized by comparing nanocomposites prepared at different pyrolysis temperatures. Ni@ZIF67 pyrolyzed at 700 °C (NZ700) exhibits the lowest OER overpotential (281 mV @ 10 mA cm−2) whereas that pyrolyzed at 500 °C reveals the lowest HER overpotential (196 mV @ 50 mA cm−2) in alkaline seawater. The NZ700||NZ700 cell also exhibits the lowest overall splitting voltage in alkaline seawater (1.72 V @ 20 mA cm−2). Detailed post-electrolysis studies are also carried out to explore the origin of the electrocatalytic activities. Furthermore, a zero-gap, flow-cell type alkaline seawater electrolyzer prototype has been fabricated to demonstrate the viability of our catalysts.

Efficient Electrocatalytic Oxidation of Glycerol to Formate Coupled with Nitrate Reduction over Cu‐Doped NiCo Alloy Supported on Nickel Foam

AbstractElectrooxidation of biomass‐derived glycerol which is regarded as a main byproduct of industrial biodiesel production, is an innovative strategy to produce value‐added chemicals, but currently showcases slow kinetics, limited Faraday efficiency, and unclear catalytic mechanism. Herein, we report high‐efficiency electrooxidation of glycerol into formate via a Cu doped NiCo alloy catalyst supported on nickel foam (Cu−NiCo/NF) in a coupled system paired with nitrate reduction. The designed Cu−NiCo/NF delivers only 1.23 V vs. RHE at 10 mA cm−2, and a record Faraday efficiency of formate of 93.8 %. The superior performance is ascribed to the rapid generation of NiIII−OOH and CoIII−OOH species and favorable coupling of surface *O with reactive intermediates. Using Cu−NiCo/NF as a bifunctional catalyst, the coupled system synchronously produces NH3 and formate, showing 290 mV lower than the coupling of hydrogen evolution reaction, together with excellent long‐term stability for up to 144 h. This work lays out new guidelines and reliable strategies from catalyst design to system coupling for biomass‐derived electrochemical refinery.

Recyclability of Zinc Palmitate-Based Composites in Fatty Acid Methyl Ester Production from Oil Feedstocks at Varied Acidity.

Zinc hydroxide nitrate (Zn5) is one of the layered metal hydroxide materials, which has been extensively reported as an effective bifunctional catalyst for biodiesel production from acidic oils. This report gives a comprehensive summary of the reactivity of Zn5 in the methanolysis of various oil feedstocks, plant oils, free fatty acids, and other acidic oils. Notably, as evidenced by this work, Zn5 is highly effective in converting acidic oils [palmitic acid/palm oil (PO)] to fatty acid methyl ester (FAME or biodiesel) at high yields ranging from 80 to 95%, withstanding acid content up to 10% without soap formation. The high FAME yields result from complex methanolysis and hydrolysis processes, e.g., transesterification of triglycerides in the PO, esterification of palmitic acid, and hydrolysis of the triglycerides. Despite this, Zn5 is nonrecyclable because it is unstable in the reaction media and transforms into zinc hydroxide nitrate/zinc palmitate (Zn5/ZnP) composites. The Zn5/ZnP composites were suitable for use in FAME production from PO at 100 °C for 2 h by using a methanol-to-oil molar ratio of 30:1, yielding high FAME yields of 97 and 70.7% in the first and fourth cycles, respectively. This study added better insight into how to effectively produce FAME from oil feedstocks of varying acidity by using zinc layered hydroxide- or zinc carboxylate-based materials.

High-Entropy Ag-Ru-Based Electrocatalysts with Dual-Active-Center for Highly Stable Ultra-Low-Temperature Zinc-Air Batteries.

The development of advanced bifunctional catalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is significant for rechargeable zinc-air batteries (ZABs). Herein, a unique dual active center alloying strategy is proposed to achieve the efficient bifunctional oxygen catalysis, and the high entropy effect is further exploited to modulate the structure and performance of the catalysts. The MOF-assisted pyrolysis-replacement-alloying method was employed to construct the CoCuFeAgRu high-entropy alloy (HEA), which are uniformly anchored in porous nitrogen-doped carbon nanosheets. Notably, the obtained HEA catalyst exhibits excellent catalytic performance for both ORR and OER, and a peak power density of 136. 53 mW cm-2 and an energy density of 987.9 mAh gZn -1, surpassing the most of the previously reported bifunctional oxygen electrocatalysts. Moreover, the assembled flexible rechargeable ZAB enables excellent performance even at the ultralow temperature of -40 °C, with an energy density of 601.6 mAh gZn -1 and remarkable cycling stability up to 1,650 hours. Combined experimental and theoretical calculation results reveal that the excellent bifunctional catalytic activity of the HEA catalyst originated from the synergistic effect of the Ag and Ru dual active centers, and the optimization of the electronic structure by alloying effect.

High‐Entropy Ag‐Ru‐based Electrocatalysts with Dual‐Active‐Center for Highly Stable Ultra‐Low‐Temperature Zinc‐Air Batteries

The development of advanced bifunctional catalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is significant for rechargeable zinc‐air batteries (ZABs). Herein, a unique dual active center alloying strategy is proposed to achieve the efficient bifunctional oxygen catalysis, and the high entropy effect is further exploited to modulate the structure and performance of the catalysts. The MOF‐assisted pyrolysis‐replacement‐alloying method was employed to construct the CoCuFeAgRu high‐entropy alloy (HEA), which are uniformly anchored in porous nitrogen‐doped carbon nanosheets. Notably, the obtained HEA catalyst exhibits excellent catalytic performance for both ORR and OER, and a peak power density of 136. 53 mW cm‐2 and an energy density of 987.9 mAh gZn‐1, surpassing the most of the previously reported bifunctional oxygen electrocatalysts. Moreover, the assembled flexible rechargeable ZAB enables excellent performance even at the ultralow temperature of ‐40°C, with an energy density of 601.6 mAh gZn‐1 and remarkable cycling stability up to 1,650 hours. Combined experimental and theoretical calculation results reveal that the excellent bifunctional catalytic activity of the HEA catalyst originated from the synergistic effect of the Ag and Ru dual active centers, and the optimization of the electronic structure by alloying effect.