ACo2O4 (A=Ni,Zn, Mn) nanostructure arrays grown on nickel foam as efficient electrocatalysts for oxygen evolution reaction

Developing highly efficient, low-cost and superior stable electrocatalysts for the oxygen evolution reaction (OER) is essential for coping with global energy shortage and environmental crisis. In this article, ACo₂O₄/NF (A = Mn, Zn, Ni) composites were synthesized via a facilely hydrothermal and calcination method and used as electrocatalytic water oxidation catalysts. The hybrid structure, chemical composition, oxidation state and surface morphology of ACo₂O₄/NF (A = Mn, Zn, Ni) has been confirmed by powder X-ray diffraction (XRD), energy dispersive X-ray (EDX), X-ray photoelectron (XPS), scanning electron microscopy (SEM), transmission Electron Microscope (TEM) and Brunaure-Emmett-Teller (BET) analysis. Such self-supported NiCo₂O₄/NF hybrid shows a smaller overpotential of 271 mV at current density of 10 mA cm^?2 in 1 M KOH, which is comparable to most reported NiCo₂O₄ materials (monomer or composite) for OER. Influence on catalytic activity of doping different metal ions in ACo₂O₄/NF was investigated systematically for the first time. Improved electrocatalytic activity of NiCo₂O₄/NF is attributed to the special homogeneous urchin-like structure and porous property.     

Facile synthesis of three-dimensional spherical Ni(OH)2/NiCo2O4 heterojunctions as efficient bifunctional electrocatalysts for water splitting

Synthesis of highly efficient, non-noble and bi-functional electrocatalysts is exceedingly challenging and necessary for water splitting devices. In this work, three-dimensional spherical Ni(OH)₂/NiCo₂O₄ heterojunctions are prepared by a one-step hydrothermal method and the hybrids are explored as efficient electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in an alkaline electrolyte via tuning different Ni/Co atomic ratios of heterojunctions. The optimized Ni(OH)₂/NiCo₂O₄ (S (1:1)) exhibits high electrocatalytic activity with an ultralow over-potential of 189 mV at 10 mA cm⁻² for the HER. With regard to the OER, the over-potential of the as-synthesized S (1:1) heterojunction is only 224 mV at the current density of 10 mA cm⁻². The improved catalytic performance of the Ni(OH)₂/NiCo₂O₄ heterojunctions is attributed to the chemical synergic combining of Ni(OH)₂ and NiCo₂O₄, large specific surface area for exposing more accessible active sites, and heterointerface for activating the intermediates that facilitates electron/electrolyte transport. The prepared catalyst exhibits good durability and stability in HER and OER catalyzing conditions. This study provides a feasible approach for the building of highly efficient bifunctional water splitting electrocatalysts and stimulates the development of renewable energy conversion and storage devices.     

Aligned Co3O4–CoOOH heterostructure nanosheet arrays grown on carbon paper with oxygen vacancies for enhanced and robust oxygen evolution

Developing efficient and stable non-noble metal oxygen evolution reaction (OER) electrocatalysts for sustainable overall water-splitting is extremely desirable but still a great challenge. Herein, we developed a facile strategy to fabricate Co₃O₄–CoOOH heterostructure nanosheet arrays with oxygen vacancies grown on carbon paper (Co₃O₄–CoOOH/CP). Benefiting from the unique 3D architecture, large surface area, synergistic effects between Co₃O₄, CoOOH and oxygen vacancies, the obtained self-supporting Co₃O₄–CoOOH/CP presents excellent electrocatalytic OER activity (low overpotentials of 245 and 390 mV at 10 and 100 mA cm⁻²) and robust long-term stability in alkaline condition. The present strategy provides the opportunities for the future rational design and discovery of high-performance non-noble metal based electrocatalysts for advanced water oxidation and beyond.     

In-situ generated P-doped NiCo2O4 nanosheet arrays with rapid charge transfer for efficient oxygen evolution reaction in alkaline solution

Exploring highly efficient electrocatalysts (OER) is critical for oxygen evolution reaction. Herein, for the first time, P-doped NiCo₂O₄ nanosheet arrays generated on nickel foam (namely P–NiCo₂O₄/NF) were constructed via a feasible protocol. Notably, the etching treatment can open the internal structure of ZIF-67 to offer more electrocatalytically active surface area, and obtained NiCo₂O₄ showed great electrocatalytic performance in OER. The introduction of P can effectively reduce the charge transfer resistance of NiCo₂O₄ and boost OER kinetics. More importantly, doping P not only improved the hydrophilicity of NiCo₂O₄, but also reduced its surface potentials, which provided convenience for the adsorption of OH⁻ over P–NiCo₂O₄/NF electrode. As expected, the P–NiCo₂O₄/NF electrode with good long-term durability displayed excellent performance for OER in alkaline solution, and an overpotential of 121.6 mV was achieved at a current density of 10 mA/cm². To sum up, current work can provide a meaningful reference to prepare electrocatalyst for efficient OER.     

One-pot preparation of Ni3S2@3-D graphene free-standing electrode by simple Q-CVD method for efficient oxygen evolution reaction

Efficient non-noble metal catalysts for the oxygen evolution reaction (OER) are particularly important in the practical applications of electrocatalytic water splitting (ECWS). Herein, based on a simple quasi chemical vapor deposition (Q-CVD) method, we fabricate a newly Ni₃S₂@3-D graphene free-standing electrode for efficient OER applications. The Ni₃S₂@3-D graphene integrates the advantageous features of 3-D graphene and Ni₃S₂ towards OER, such as more interfacial catalytic sites, pore-rich structure, N-doped structure and good electrical conductivity. Benefiting from the favorable features, the Ni₃S₂@3-D graphene (especially 900 °C sample) exhibits excellent OER performances in alkaline medium, which includes a low on-set potential (1.53 V), low overpotential of 305 mV at a current density of 10 mA cm⁻², and a smaller Tafel slope (50 mV dec⁻¹). This catalyst also shows ultrahigh stability after chronoamperometry response at 10 mA cm⁻² for 48 h with 30% increase in the current density. The present work opens a new approach for the one-pot construction of hybrid materials between metal sulfide and graphene to increase the electrocatalytic activity of non-noble metal OER catalysts.     

Metal tungstate dominated NiCo2O4@NiWO4 nanorods arrays as an efficient electrocatalyst for water splitting

One of the most promising ways to produce high purity hydrogen is electrocatalytic water splitting, the slow rate of oxygen evolution reaction (OER) limited the whole water splitting process under alkaline conditions. Here, NiCo₂O₄@NiWO₄/NF is firstly acted as a metal tungstate dominated bifunctional water splitting catalyst, which a very low cell voltage of 1.59 V is obtained with 10 mA cm⁻² in alkaline media. Remarkably, the catalytic performance of NiCo₂O₄@NiWO₄/NF is also kept for at least 12 h, which shows long time electrochemical stability.     

Hierarchical NiCo2O4 and NiCo2S4 nanomaterials as electrocatalysts for methanol oxidation reaction

In this work, Ni foam supported hierarchical NiCo₂O₄ nanomaterials are successfully prepared through a hydrothermal process and subsequent calcination process, then the hierarchical NiCo₂O₄ is converted to hierarchical NiCo₂S₄ through a hydrothermal anion exchange process. The hierarchical nanomaterials are constructed by a nanorod core and nanoribbons shell. The morphology evolution mechanism of the hierarchical NiCo₂O₄ is studied by exploratory experiments, the results show that the morphology evolution from nanorod to hierarchical nanostructure undergo a solid–solid process, and the calcination temperature is crucial for the formation of the hierarchical nanostructure. The hierarchical NiCo₂O₄ and NiCo₂S₄ nanomaterials are both used as electrocatalysts for methanol oxidation reaction in alkaline electrolyte, and the electrocatalytic activity of the NiCo₂S₄ is higher than that of the NiCo₂O₄. Cycling test shows the good stability of the NiCo₂S₄, and the slight loss of activity during cycling is caused by the surface oxidation of NiCo₂S₄ in alkaline electrolyte. This work indicate that the hierarchical NiCo₂S₄ is a promising non-noble metal electrocatalyst for direct methanol fuel cells.     

ZIF-67-derived Co,Ni and S co-doped N-enriched porous carbon polyhedron as an efficient electrocatalyst for oxygen evolution reaction (OER)

Rational fabrication of highly efficient and non-precious metal electrocatalysts for oxygen evolution reaction (OER) are of great importance for renewable energy exploitation to solving the energy crisis and environmental problems. In this paper, we report a novel hybrid nanostructure with Co, Ni and S co-doped N-enriched porous carbon polyhedron (CoNi_xS_y/NCP) via a absorption-pyrolysis-sulfuration strategy derived from zeolitic imidazolate framework-67 (ZIF-67) and explored its electrocatalytic performance for OER. During the synthesis process, Ni²⁺ is abosrbed within the pores or surface of ZIF-67 and Ni/ZIF-67 can be transformed into the Co and Ni co-doped porous carbon frameworks when it is sulfurazed at 800 °C. NiS₂ and NiCo₂S₄ nanoparticles formed at high temperature are homogeneously dispersed in porous carbon and can activate its electrocatalytic performance. The porous carbon can enhance the electrochemical surface area and charge transfer efficiency. Benefiting from the synergistic effects between highly active NiS₂, NiCo₂S₄, and porous carbon, CoNi_xS_y/NCP electrocatalyst exhibits excellent electrocatalytic performance. The results show that CoNi_xS_y/NCP also exhibits a potential as low as 1.51 V to achieve 10 mA/cm² current density and extremely stability towards OER. The good electrocatalytic activity of CoNi_xS_y/NCP further suggest its great potential as an efficient eletctocatalyst for sustainable energy applications.     

Metal–organic framework derived CoS2/FeS-MOF with abundant heterogeneous interface as bifunctional electrocatalyst for electrolysis of water

Highly active and stable non-precious metal dual-functional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are very important for the industrialization of water electrolysis. Herein, a three-dimensional (3D) porous CoS₂/FeS-MOF with adjustable Co/Fe molar ratio are in-stiu grown on a nickel foam (NF) to get a binder-free electrocatalyst electrode for HER and OER (CoS₂/FeS-MOF@NF). It should be emphasized that the MOFs precursor forms abundant heterogeneous interfaces through in-situ sulfidation. Moreover, the open skeleton and ordered porous structure of MOFs will not be destroyed due to the low temperature. The redistribution of electrons at the heterogeneous interfaces will produce more catalytic active centers, providing more active sites for reactant molecules or intermediates, thus availably promoting the electrocatalytic activity of the composite. Therefore, the optimized catalyst CoS₂/FeS-MOF@NF-1 displays high OER activity. The overpotential is only 136 mV at 10 mA cm^?2. At the same time, the CoS₂/FeS-MOF@NF-1 also shows good HER catalytic activity. Therefore, the assembled corresponding symmetric electrolyzer CoS₂/FeS-MOF@NF-1||CoS₂/FeS-MOF@NF-1 achieves a low cell voltage of 1.5 V at 10 mA cm^?2 with long time stability for 24 h. This work provides a simple and convenient strategy for the synthesis of transition metal sulfides dual-function electrocatalysts.     

Fe-doped NiCo2S4 catalyst derived from ZIF – 67 towards efficient hydrogen evolution reaction

The development of economical, efficient and stable non-noble metal catalysts plays a key role in electrocatalytic hydrogen evolution. NiCo₂S₄ has been proved to be an efficient non-noble catalyst, to further improve its electrocatalytic performance is a meaningful work. In this paper, the effects of Fe doping on electrochemical performance of NiCo₂S₄ is investigated. The Fe-doped NiCo₂S₄ catalyst is prepared by a facile solvothermal method with metal-organic-framework (MOF, ZIF-67) as template, and it exhibits an improved hydrogen evolution reaction (HER) performance with an overpotential of 181 mV at 10 mA cm^?2, a Tafel slope of 125 mV dec^?1 compared with that of NiCo₂S₄ (252 mV overpotential and 149 mV dec^?1 Tafel slope). The combination of improved conductivity, mesopores architecture retained with the ZIF-67 template, which result the reduced internal resistance, enhanced charge transportation as well as large electrochemical double-layer capacitance. This work provides an effective and synergistic strategy for fabricating NiCo₂S₄-based catalysts toward electrochemical water splitting.     

An efficient palladium oxide nanoparticles@Co3O4 nanocomposite with low chemisorbed species for enhanced oxygen evolution reaction

Significant progress has been made in recent time to design and synthesize highly efficient and cost effective electrocatalysts for oxygen evolution reaction (OER). However, the electrocatalytic activity of most recently reported materials is limited by the large onset potential, poor electrical conductivity and low density of catalytic centers. In this study, we report facile deposition of palladium oxide nanoparticles onto cobalt oxide nanostructures (PdONPs@Co₃O₄) through the illumination of ultraviolet (UV) light. The fabricated PdONPs@Co₃O₄ nanocomposites offer high density of active sites, improved electrical conductivity and durability for OER activity. The synergetic effect between the Co and Pd ions at the interface of composite system might change the adsorption energy of reaction intermediates, thus enabled the reaction to proceed at lower energy consumption. Significantly, the prepared PdONPs@Co₃O₄ samples demonstrated a low overpotential of 250 mV at a current density of 20 mA/cm², with low charge transfer resistant of 48.5 Ωand high durability for more than 40 h during OER processes. The combined results suggest that incorporating of a low amount of PdONPs can tune the surface properties of Co₃O₄ and interfacial chemistry. This could led to accelerate the charge transport properties at the interface during a specific electrochemical application.     

Enhanced oxygen evolution reaction kinetics through biochar-based nickel-iron phosphides nanocages in water electrolysis for hydrogen production

Highly-efficient and stable non-noble metal electrocatalysts for overcoming the sluggish kinetics of oxygen evolution reaction (OER) is urgent for water electrolysis. Biomass-derived biochar has been considered as promising carbon material because of its advantages such as low-cost, renewable, simple preparation, rich structure, and easy to obtain heteroatom by in-situ doping. Herein, Ni₂P–Fe₂P bimetallic phosphide spherical nanocages encapsulated in N/P-doped pine needles biochar is prepared via a simple two-step pyrolysis method. Benefiting from the maximum synergistic effects of bimetallic phosphide and biochar, high conductivity of biochar encapsulation, highly exposed active sites of Ni₂P–Fe₂P spherical nanocages, rapid mass transfer in porous channels with large specific surface area, and the promotion in adsorption of reaction intermediates by high-level heteroatom doping, the (Ni_0.75Fe_0.25)₂P@NP/C demonstrates excellent OER activity with an overpotential of 250 mV and a Tafel slope of 48 mV/dec at 10 mA/cm² in 1 M KOH. Also it exhibits a long-term durability in 10 h electrolysis and its activity even improves during the electrocatalytic process. The present work provides a favorable strategy for the inexpensive synthesis of biochar-based transition metal electrocatalysts toward OER, and improves the water electrolysis for hydrogen production.     

Controlled synthesis of NiCo2O4@Ni-MOF on Ni foam as efficient electrocatalyst for urea oxidation reaction and oxygen evolution reaction

Heterostructured materials with special interfaces and features give a unique character for much electrocatalytic process. In this work, the introduction of exogenous modifier Ni-MOF improved the reaction kinetics and morphology of the NiCo₂O₄@Ni-MOF/NF catalyst. As-obtained NiCo₂O₄@Ni-MOF/NF has excellent oxygen evolution reaction (OER) performance and urea oxidation reaction (UOR) performance. The catalyst need overpotential of 340 mV at a current density of 100 mA cm^?2 for OER and a potential of 1.31 V at the same current density for UOR. The Tafel slopes of NiCo₂O₄@Ni-MOF/NF is 38.34 and 15.33 mV dec^?1 for OER and UOR respectively, which is more superior than 78.58 and 66.73 mV dec^?1 of NiCo₂O₄/NF. The nanosheets microstructure is beneficial to the adsorption and transport of electrolyte and the presence of a large number of mesoporous channels can also accelerate gas release, and then improves activity of the catalyst. Density functional theory calculation demonstrate that NiCo₂O₄ plays a role in absorbing water, while the existence of in situ generated NiOOH can promote the electron transfer efficiency. It is synergies of NiCo₂O₄ and in situ generated NiOOH that enhance the decomposition of water on the surface of the NiCo₂O₄@Ni-MOF/NF. This investigation provides a new strategy for the application of spinel oxide and MOF materials.     

NiCo2O4 nanostructures loaded onto pencil graphite rod: An advanced composite material for oxygen evolution reaction

Driving oxygen evolution reaction (OER) at extremely low overpotential and the blockage of oxygen gas inside the catalytic material leads to the deactivation of catalytic activity, therefore it is an essential step in electrochemical energy conversion systems, but still very challenging task. The clay minerals including bentonite and kaolinite are rich with plenty of active centers and favorable chemical composition for the catalysis applications but limited by the insulating properties, thus they cannot be used as an electrode material for the water splitting. The unique presence of clay minerals in the form of pencil graphite rod (PGR) and its attractive architecture enabled us to exploit advantageous features and use them as an in situ electrode for growth of metal oxide nanostructures for the electrolysis applications. The naturally inherent presence of SiO₂ favors the catalytic properties and durability of the electrode whereas the MgO produces the abundant oxygen vacancies and Co³⁺ ions for OER process. Herein, we present a facile approach of using PGR as host substrate and co-catalyst for the loading of Co₃O₄, NiCo₂O₄ and NiO nanostructures and the modified electrode carried high porosity for easily bubbling of oxygen gas, plenty of intrinsic active centers coming from both clay minerals and metal oxides for excellent OER process. The fabricated electrode is physically well-characterized, and it has a natural ability to sustain a long term stability even at higher current densities and industrial electrolyzer conditions. The NiCo₂O₄/PGR, Co₃O₄/PGR, and NiO/PGR electrodes exhibit an overpotential of 234, 242 and 272 mV respectively at a current density of 100 mAcm^?2 in 1.0 M KOH electrolytic solution. The presence of large number of oxygen vacancies through SiO₂ and MgO, high Ni²⁺/Ni³⁺ and Co³⁺/Co²⁺ ratios, multi metal centers, large specific surface area, high pore volume, high electrochemical active surface area and fast charge transport within the NiCo₂O₄/PGR are the main reasons for its superfast OER kinetics. Thus, the proposed method of electrode design will pave a potential way for high performance electrochemical devices like metal air batteries, fuel cell and supercapacitors.     

Facile synthesis of tubular CoP as a high efficient electrocatalyst for pH-universal hydrogen evolution

A facile three-step approach for tubular CoP preparation and its catalytic activity for HER and OER are reported. The CoP microtubes show superior HER performance in a wide pH range with low overpotentials of 91, 101 and 113 mV at 10 mA cm^?2 in 0.5 M H₂SO₄, 1 M KOH and 1 M PBS, respectively. Additionally, it also depicts superior OER performance with an overpotential of 300 mV at 10 mA cm^?2, which is lower than reported precious metal oxides. The improved electrocatalytic performance of tubular CoP is likely attributed to the porous tube-like structural features, which not only afford rich exposed active sites, but also accelerate the charge or mass transfer efficiency, and thus efficiently promote the HER performance. The synthesis of tubular CoP confirms the importance of morphology features and provides a new insight to rationally design and synthesize highly effective non-noble metal phosphide-based pH-universal electrocatalysts for HER.     

Manganese oxide embedded graphene nanohybrid for pH-universal electrochemical overall water splitting

Efficient non-noble metal bifunctional electrocatalysts for overall water splitting in pH universal is highly desired in application. Herein, MnO₂/graphene composition are applied as efficient electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in pH-universal electrolytes with the help of plasma dc arc method. The couple of MnO₂ and graphene highly benefits to the H₂O, H⁺ and OH⁻ absorption respectively. The defects and stable Mn³⁺ contribute to the transfer of electron and charge. The low overpotentials and small Tafel slopes reveal attractive activities of HER and OER. The good electrocatalytic performances are attributed to the synergistic effect and abundant heterogeneous interfaces in MnO₂/graphene. These can offer rich electroactive sites and accelerate electron transfer. Thus, it may provide facile route for developing nonprecious electrocatalysts of water splitting.     

Recent advances in Ni3S2-based electrocatalysts for oxygen evolution reaction

The preparation of hydrogen by electrolysis of water has the characteristics of easily available raw materials, simple process and eco-friendly, which has aroused the interest of many researchers. However, the inherent high reaction energy barrier and four-electron reaction mechanism of oxygen evolution reaction (OER) lead to large reaction overpotential, slow reaction rate and high energy consumption, resulting in low hydrogen evolution efficiency of the cathodic half-reaction, which greatly limits its practical application. Ni₃S₂ has a heazlewoodite structure. Due to the inherent Ni–Ni metal network, it has near-metal conductivity, which has attracted great attention in the application of electrocatalytic OER. Therefore, this article reviews the application of Ni₃S₂ and its composites in OER. The composition, structure and electrochemical catalytic performance were systematically summarized. It can be believed that Ni₃S₂-based materials will have a wide application prospect as OER electrocatalysts in the future.     

Nanosheet self-assembled NiCoP microflowers as efficient bifunctional catalysts (HER and OER) in alkaline medium

Developing greatly efficient and steady non-noble metal bifunctional electrocatalyst is of great significance for reducing the energy consumption. In this work, we found that the construction of hierarchical nanostructures was an effective strategy to improve the catalytic performance of bimetallic transition-metal phosphide (NiCoP). Herein, we successfully synthesized the Ni_1.5Co_1.5P catalyst with porous nanosheet self-assembled microflowers (MFs) structure by sequential solvothermal, annealing and phosphorization treatment, and then adjusted the morphology of the MFs by changing the Ni/Co molar ratio to optimize its electronic structure and increase the exposed active sites, thereby improving catalytic activity of the catalyst. Specifically, the Ni_1.5Co_1.5P/MFs only required overpotentials of 141 mV and 314 mV to reach a current density of 10 mA cm⁻² toward HER and OER, respectively. Impressively, during the continuous 12 h chronoamperometry measurement, the Ni_1.5Co_1.5P/MFs displayed good durability. In conclusion, this study provided a feasible strategy to explore and prepare low-cost non-noble metal bifunctional electrocatalysts.     

Fe3C nanoparticles-loaded 3D nanoporous N-doped carbon: A highly efficient electrocatalyst for oxygen reduction in alkaline media

High-performance, non-precious metal electrocatalysts have been widely considered among the most prospective candidates to replace Pt-based electrocatalysts for the oxygen reduction reaction (ORR) in fuel cells and metal-air batteries. Herein, we report a synthetic method, involving templating, polymerization and pyrolysis, that produces catalytically active iron carbide (Fe₃C) nanoparticles-loaded porous N-doped carbon materials from polyaniline- and Fe(III)-modified mesoporous graphitic carbon nitride (g-C₃N₄). We also show that the resulting noble metal-free materials exhibit good electrocatalytic activity for ORR, with good onset and half-wave potentials, in O₂-saturated alkaline solution. The structure, composition, crystallinity, and electrocatalytic activity of these materials are found to depend on the pyrolysis temperature and the specific components in the precursor. In particular, the material obtained by pyrolysis at 1000 °C, named Fe₃C/NC-1000, shows excellent electrocatalytic activity and better performance, in terms of both onset and half-wave potentials, than Pt/C (20 wt% Pt). The material also tolerates the methanol crossover reaction better than Pt/C and shows negligible shift in onset and half-wave potentials to negative values even after use in 3000 cycles of electrocatalysis. This robust, non-noble metal-based carbon material can potentially become a viable alternative to precious metal electrocatalysts for ORR.     

Role of macrocyclic salen-type Schiff base ligands in one-dimensional Co(II) complexes for superior activities toward oxygen reduction/evolution reactions

Developing high activities, stable, non-precious metal based bi-functional electrocatalysts oxygen evolution/reduction reactions (OER/ORR) in rechargeable metal-air batteries and regenerative fuel cell technologies is essential for future energy conversion and storage. In this work, the potential of utilizing the synthesized one-dimensional transition metal salen-type complexes (TM-SCs) as bi-functional electrocatalysts of ORR and OER is systematically explored by computational screening approach. The results demonstrate that different types of macrocyclic ligands, including N₂O₂, N₃O and N₄ as donor groups around the active sites, govern the OER/ORR catalytic performances. Co–SCs with N₂O₂ ligands exhibit the highest bifunctional catalytic activities. In particular, low limiting overpotentials of 0.22 V for OER and 0.33 V for ORR can be observed on Co sites, which are even superior to those of noble metal catalysts. Analyzing the linear relationships between the adsorption strength of intermediates and the overpotentials shows that the origin of excellent electrocatalytic performance is the smaller slope (0.86) for OOH1 vs OH1 on TM-SCs compared to metal surfaces, resulting in strengthened binding of the OOH1 intermediate. Besides, the adsorption energies of the intermediates bound on Co–N₂O₂ are close to the ideal values, while too strong on the Co–N₃O and Co–N₄ catalysts. By applying external strains, the adsorption strengths of reaction intermediates can be further modulated due to the tunable d-band centers, and the resulting ORR/OER activities are further boosted. Considering that the Co salen-based chain has been synthesized experimentally, this work highlights the excellent electrocatalytic performances of this new material and devises novel strategy by straining for catalyst optimizations.