FeCoCuMnRuB Nanobox with Dual Driving of High-Entropy and Electron-Trap Effects as the Efficient Electrocatalyst for Water Oxidation.

High-entropy borides hold potential as electrocatalysts for water oxidation. However, the synthesis of the tailored nanostructures remains a challenge due to the thermodynamic immiscibility of polymetallic components. Herein, a FeCoCuMnRuB nanobox decorated with a nanosheet array was synthesized for the first time by a "coordination-etch-reduction" method. The FeCoCuMnRuB nanobox has various structural characteristics to express the catalytic performance; meanwhile, it combines the high-entropy effect of multiple components with the electron trap effect induced by electron-deficient B, synergistically regulating its electronic structure. As a result, FeCoCuMnRuB nanobox exhibits enhanced OER activity with a low overpotential (η10 = 233 mV), high TOF value (0.0539 s-1), small Tafel slope (61 mV/dec), and a satisfactory stability for 200 h, outperforming the high-entropy alloy and low-entropy borides. This work develops a high entropy and electron-deficient B-driven strategy for motivating the catalytic performance of water oxidation, which broadens the structural diversity and category of high-entropy materials.

Atomic Layer Engineering of Pd Nanosheets for an Enhanced Hydrogen Evolution Reaction.

Thickness control of two-dimensional (2D) metal nanosheets (metallenes) has scientific significance for energy and catalyst applications, yet is unexplored owing to the lack of an efficient approach for the tailored synthesis of metallenes with controlled atomic layers. Here we report a 2D template-directed synthesis of ultrathin Pd nanosheets with well-controlled thicknesses. Molecularly thin single-crystalline Pd nanosheets with well-defined hexagonal morphologies were synthesized via a one-pot method with 2,4,6-trichlorophenyl formate. Such Pd nanosheets were used as hard templates for the tailored synthesis of the Pd nanosheets with controlled thicknesses (9, 11, 13, and 15 atomic layers). Hard X-ray photoelectron spectroscopy and density functional theory calculations revealed unique electronic states in thickness-controlled Pd nanosheets; these states included reduced surface charges to bulk, increased work functions, and decreased d-band centers. Thus, atomic layer engineering of Pd nanosheets enabled the fine-tuning of the surface electronic states to improve the hydrogen evolution reaction.

Corrosion Dynamics of Carbon-Supported Platinum Electrocatalysts with Metal-Carbon Interactions Revealed by In Situ Liquid Transmission Electron Microscopy.

Carbon support is essential for electrocatalysis, but limitations remain, as carbon corrosion can lead to electrocatalyst degradation and affect the long-term durability of electrocatalysts. Here, we studied the corrosion dynamics of carbon nanotubes (CNTs) and Vulcan carbon (VC) together with platinum (Pt) nanoparticles in real time by liquid cell (LC) transmission electron microscopy (TEM). The results showed that CNTs with a high degree of graphitization exhibited higher corrosion resistance compared to VC. Furthermore, we observed that the main degradation path of Pt nanoparticles in Pt/CNTs was ripening, while in Pt/VC, it was aggregation and coalescence, which was dominated by the interactions between Pt nanoparticles and different hybridization of carbon supports. Finally, we performed an ex situ CV stability test to confirm the conclusions obtained from in situ experiments. This work provides deep insights into the corrosion mechanism of carbon-supported electrocatalysts to optimize the design of electrocatalysts with a higher durability.

Accelerating the Discovery of Efficient High-Entropy Alloy Electrocatalysts: High-Throughput Experimentation and Data-Driven Strategies.

High-entropy alloys (HEAs) present both significant potential and challenges for developing efficient electrocatalysts due to their diverse combinations and compositions. Here, we propose a procedural approach that combines high-throughput experimentation with data-driven strategies to accelerate the discovery of efficient HEA electrocatalysts for the hydrogen evolution reaction (HER). This enables the rapid preparation of HEA arrays with various element combinations and composition ratios within a model system. The intrinsic activity of the HEA arrays is swiftly screened using scanning electrochemical cell microscopy (SECCM), providing precise composition-activity data sets for the HEA system. An ensemble machine learning (EML) model is then used to predict the activity database for the composition subspace of the system. Based on these database results, two groups of promising catalysts are recommended and validated through actual electrocatalytic evaluations. This procedural approach, which combines high-throughput experimentation with data-driven strategies, provides a new pathway to accelerate the discovery of efficient HEA electrocatalysts.

Unlocking the Potential of Nanobubbles: Achieving Exceptional Gas Efficiency in Electrogeneration of Hydrogen Peroxide.

The electrogeneration of hydrogen peroxide (H2 O2 ) via the oxygen reduction reaction is a crucial process for advanced water treatment technologies. While significant effort is being devoted to developing highly reactive materials, gas provision systems used in these processes are receiving less attention. Here, using oxygen nanobubbles to improve the gas efficiency of the electrogeneration of H2 O2 is proposed. Aeration with nanobubbles is compared to aeration with macrobubbles under an identical experimental set-up, with nanobubbles showing a much higher gas-liquid volumetric mass transfer coefficient (KL a) of 2.6 × 10-2 min-1 compared to 2.7 × 10-4 min-1 for macrobubbles. Consequently, nanobubbles exhibit a much higher gas efficiency using 60% of O2 delivered to the system compared to 0.19% for macrobubbles. Further, it is observed that the electrogeneration of H2 O2 using carbon felt electrodes is enhanced using nanobubbles. Under the same dissolved oxygen levels, nanobubbles boost the reaction yield to 84%, while macrobubbles yield only 53.8%. To the authors' knowledge, this is the first study to investigate the use of nanobubbles in electrochemical reactions and demonstrate their ability to enhance gas efficiency and electrocatalytic response. These findings have important implications for developing more efficient chemical and electrochemical processes operating under gas-starving systems.

In Situ Construction of Zinc-Mediated Fe, N-Codoped Hollow Carbon Nanocages with Boosted Oxygen Reduction for Zn-Air Batteries.

The rational design of bifunctional oxygen electrocatalysts with unique morphology and luxuriant porous structure is significant but challenging for accelerating the reaction kinetics of rechargeable Zn-air batteries (ZABs). Herein, zinc-mediated Fe, N-codoped carbon nanocages (Zn-FeNCNs) are synthesized by pyrolyzing the polymerized iron-doped polydopamine on the surface of the ZIF-8 crystal polyhedron. The formation of the chelate between polydopamine and Fe serves as the covering layer to prevent the porous carbon nanocages from collapsing and boosts enough exposure and utilization of metal-based active species during carbonization. Furthermore, both the theoretical calculation and experimental results show that the strong interaction between polyhedron and polydopamine facilitates the evolution of high-activity zinc-modulated FeNx sites and electron transportation and then stimulates the excellent bifunctional catalytic activity for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). As expected, the Zn-air battery with Zn-FeNCNs as an air cathode displays a superior power density (256 mW cm-2) and a high specific capacity (813.3 mA h gZn-1), as well as long-term stability over 1000 h. Besides, when this catalyst is applied to the solid-state battery, the device exhibited outstanding mechanical stability and a high round-trip efficiency under different bending angles.

In Situ Carbon Thermal Reduction to Enrich Sulfur-Vacancy in Nickel Disulfide Cathode for Efficient Synthesizing Hydrogen Peroxide.

Transition metal catalysts are widely used in the 2e- ORR due to their cost-effectiveness. However, they often encounter issues related to low activity. Defect engineering are used on developing highly active catalysts, which can effectively modify active sites and promote electron transfer. Here, carbon-coated Ni3S2 (Ni3S2@C), where the additional sulfur vacancies (VS) is prepared induced by the carbon layer is coupled with active nickel sites. Through in situ and ex situ experiments combined with DFT calculations, it is demonstrated that the carbon layer can regulate the quantity of VS in Ni3S2. Materials with a higher concentration of VS exhibit enhanced 2e- ORR activity and higher H2O2 selectivity. In situ Raman spectroscopy confirms that Ni serves as the key active site in this catalyst. DFT calculations indicate that the OOH binding energy (ΔG) decreases with an increase in the number of VS, favoring the protonation of *OOH to generate H2O2. Upon performance testing, the average H2O2 selectivity is 92.3%, with the highest yield reaching up to 3860 mmol gcat-1 h-1. It is noteworthy that Ni3S2@C exhibits high stability, with only a slight decrease in 2e- pathway selectivity after 5000 cycles of ADT.

Scalable Cathodic H2O2 Electrosynthesis using Cobalt-Coordinated Nanocellulose Electrocatalyst.

Converting hierarchical biomass structure into cutting-edge architecture of electrocatalysts can effectively relieve the extreme dependency of nonrenewable fossil-fuel-resources typically suffering from low cost-effectiveness, scarce supplies, and adverse environmental impacts. A cost-effective cobalt-coordinated nanocellulose (CNF) strategy is reported for realizing a high-performance 2e-ORR electrocatalysts through molecular engineering of hybrid ZIFs-CNF architecture. By a coordination and pyrolysis process, it generates substantial oxygen-capturing active sites within the typically oxygen-insulating cellulose, promoting O2 mass and electron transfer efficiency along the nanostructured Co3O4 anchored with CNF-based biochar. The Co-CNF electrocatalyst exhibits an exceptional H2O2 electrosynthesis efficiency of ≈510.58 mg L-1 cm-2 h-1 with an exceptional superiority over the existing biochar-, or fossil-fuel-derived electrocatalysts. The combination of the electrocatalysts with stainless steel mesh serving as a dual cathode can strongly decompose regular organic pollutants (up to 99.43% removal efficiency by 30 min), showing to be a desirable approach for clean environmental remediation with sustainability, ecological safety, and high-performance.

OH Regulator of Amorphous CrOx on Defect-Rich Ultrafine Pd Nanowires Boosts Electrocatalytic Ethanol Oxidation.

Reasonable construction of high activity and selectivity electrocatalysts is crucial to achieve efficient ethanol oxidation reaction (EOR). However, the oxidation of ethanol tends to produce CO species that poison the active centers of the EOR electrocatalysts. Herein, a unique amorphous CrOx-protected defect-rich ultrafine Pd nanowires (CrOx-Pd NWs) is developed. On the one hand, the CrOx layer can act as a protective layer to maintain the structure of the nanowire. On the other hand, it can play the role of OH regulator to optimize the adsorption energy barrier of intermediate species in Pd nanowire, thereby enhancing the ability of the catalyst to resist CO poisoning. The CrOx-Pd NWs exhibit excellent EOR performance with 3.64 times higher mass activity and 50 mV lower CO electro-oxidation potential than commercial Pd black. The results show that the CrOx layer promotes the dissociation of H2O into OHads, while the CrOx transfers electrons to neighboring Pd atoms optimizing the electronic configuration of Pd, thus selectively oxidizing ethanol to acetate and preventing the formation of toxic *CO. This work provides an effective strategy for the synthesis of nanowire materials with oxide/metal interfaces and offers new ideas for the design of catalysts that can efficiently drive EOR.

High-Energy Facet Engineering for Electrocatalytic Applications.

The design of high-energy facets in electrocatalysts has attracted significant attention due to their potential to enhance electrocatalytic activity. In this review, the significance of high-energy facets in various electrochemical reactions are highlighted, including oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), nitrogen reduction reaction (NRR), and carbon dioxide reduction reaction (CRR). Their importance in various electrochemical reactions and present strategies for constructing high-energy facets are discussed, including alloying, heterostructure formation, selective etching, capping agents, and coupling with substrates. These strategies enable control over crystallographic orientation and surface morphology, fine-tuning electrocatalytic properties. This study also addresses future directions and challenges, emphasizing the need to better understand fundamental mechanisms. Overall, high-energy facets offer exciting opportunities for advancing electrocatalysis.

Bimetallic Sulfur-Doped Nickel-Cobalt Selenides as Efficient Bifunctional Electrocatalysts for the Complete Decomposition of Water.

The creation and enhancement of non-precious metal bifunctional catalysts with superior stability and stabilizing activity is necessary to achieve water splitting in alkaline media. The paper presents a method for preparing nickel-cobalt bimetallic selenides (NiCo-Sex/CF) using a combination of hydrothermal and high-temperature selenization techniques. NiCo-Sex/CF shows great potential as a catalyst for water separation. The catalyst's electronic structure and active centre can be modified by double doping with sulfur and selenium, resulting in increased selectivity and activity under varying reaction conditions. This method also offers the benefits of a simple preparation process and applicability to a wide range of catalytic reactions. Experimental results demonstrate that an overpotential of 194 mV produces a current density of 10 mA cm-2 when using this electrocatalyst as an OER catalyst. When used as a HER catalyst, the electrocatalyst required an overpotential of only 76 mV to generate a current density of 10 mA cm-2.Furthermore, a voltage of 1.5 V can drive the overall decomposition of water to achieve a current density of 10 mA cm-2. This study highlights the potential of sulfur-selenide double-doped catalysts for both scientific research and practical applications.

In Situ Engineering Multifunctional Active Sites of Ruthenium-Nickel Alloys for pH-Universal Ampere-Level Current-Density Hydrogen Evolution.

Developing robust non-platinum electrocatalysts with multifunctional active sites for pH-universal hydrogen evolution reaction (HER) is crucial for scalable hydrogen production through electrochemical water splitting. Here ultra-small ruthenium-nickel alloy nanoparticles steadily anchored on reduced graphene oxide papers (Ru-Ni/rGOPs) as versatile electrocatalytic materials for acidic and alkaline HER are reported. These Ru-Ni alloy nanoparticles serve as pH self-adaptive electroactive species by making use of in situ surface reconstruction, where surface Ni atoms are hydroxylated to produce bifunctional active sites of Ru-Ni(OH)2 for alkaline HER, and selectively etched to form monometallic Ru active sites for acidic HER, respectively. Owing to the presence of Ru-Ni(OH)2 multi-site surface, which not only accelerates water dissociation to generate reactive hydrogen intermediates but also facilitates their recombination into hydrogen molecules, the self-supported Ru90Ni10/rGOP hybrid electrode only takes overpotential of as low as ≈106 mV to deliver current density of 1000 mA cm-2, and maintains exceptional stability for over 1000 h in 1 m KOH. While in 0.5 m H2SO4, the Ru90Ni10/rGOP hybrid electrode exhibits acidic HER catalytic behavior comparable to commercially available Pt/C catalyst due to the formation of monometallic Ru shell. These electrochemical behaviors outperform some of the best Ru-based catalysts and make it attractive alternative to Pt-based catalysts toward highly efficient HER.

Ultra-Rapid Electrocatalytic H2O2 Fabrication over Mono-Species and High-Density Polypyrrolic-N Sites.

Electrocatalytic hydrogen peroxide (H2O2) production via two-electron oxygen reduction reaction (2e--ORR) features energy-saving and eco-friendly characteristics, making it a promising alternative to the anthraquinone oxidation process. However, the common existence of numerous 2e--ORR-inactive sites/species on electrocatalysts tends to catalyze side reactions, especially under low potentials, which compromises energy efficiency and limits H2O2 yield. Addressing this, a high surface density of mono-species pyrrolic nitrogen configurations is formed over a polypyrrole@carbon nanotube composite. Thermodynamic and kinetic calculation and experimental investigation collaboratively confirm that these densely distributed and highly selective active sites effectively promote high-rate 2e--ORR electrocatalysis and inhibit side reactions over a wide potential range. Consequently, an ultra-high and stable H2O2 yield of up to 67.9/51.2 mol g-1 h-1 has been achieved on this material at a current density of 200/120 mA cm-1, corresponding Faradaic efficiency of 72.8/91.5%. A maximum H2O2 concentration of 13.47 g L-1 can be accumulated at a current density of 80 mA cm-1 with satisfactory stability. The strategy of surface active site densification thus provides a promising and universal avenue toward designing highly active and efficient electrocatalysts for 2e--ORR as well as a series of other similar electrochemical processes.

Optimizing Hydrogen and Hydroxyl Adsorption over Ru/WO2.9 Metal/Metalloid Heterostructure Electrocatalysts for Highly Efficient and Stable Hydrogen Oxidation Reactions in Alkaline Media.

The development of high-performance, stable and platinum-free electrocatalysts for the hydrogen oxidation reaction (HOR) in alkaline media is crucial for the commercial application of anion exchange membrane fuel cells (AEMFCs). Ruthenium, as an emerging HOR electrocatalyst with a price advantage over platinum, still needs to solve the problems of low intrinsic activity and easy oxidation. Herein, Ru nanoparticles are anchored on the oxygen-vacancy-rich metalloid WO2.9 by interfacial engineering to create abundant and efficient Ru and WO2.9 interfacial active sites for accelerated HOR in alkaline media. Ru/WO2.9/C displays excellent catalytic activity with mass activity (8.29 A mgNM -1) and specific activity (1.32 mA cmNM -2), which are 2.5/3.3 and 21.8/8.3 times that of PtRu/C and Pt/C, respectively. Moreover, Ru/WO2.9/C exhibits excellent CO tolerance and operational stability. Experimental and theoretical studies reveal that the improved charge transfer from Ru to WO2.9 in the metal/metalloid heterostructure significantly tune the electronic structure of Ru sites and optimize the hydrogen binding energy (HBE) of Ru. While, WO2.9 provides abundant hydroxyl adsorption sites. Therefore, the equilibrium adsorption of hydrogen and hydroxyl at the interface of Ru/WO2.9 will be realized, and the oxidation of metal Ru would be avoided, thereby achieving excellent HOR activity and durability.

Boosting the ORR/OER Activity of Cobalt-Based Nano-Catalysts by Co 3d Orbital Regulation.

The transition metal oxides/sulfides are considered promising catalysts due to their abundant resources, facile synthesis, and reasonable electrocatalytic activity. Herein, a significantly improved intrinsic catalytic activity is achieved for constructing a Co-based nanocrystal (Co-S@NC) with the coordination of Co─S, Co─S─C, and Co─Nx─C. The calculational and experimental results demonstrate that the diversified chemical environment of Co-cations induces the transition of 3d orbitals to a high spin-state that exhibits the coexistence of Co2+ with fully occupied dπ orbitals and Co3+ with unpaired electrons in dπ orbitals. The diverse dπ orbitals occupation contributes to an elevated d-band center of Co ions, which accelerates oxygen reduction reaction and oxygen evolution reaction electrocatalytic kinetics of the Co-S@NC nanocrystal. Therefore, the Li-O2 batteries with Co-S@NC as cathode catalyst exhibit 300 cycles at the current density of 500 mA g-1 with a cut-off capacity of 1000 mAh g-1. Moreover, the ultrahigh discharge specific capacity of 34 587 mAh g-1 is obtained at a current density of 1000 mA g-1, corresponding to the energy density 949 Wh kg-1 of a prototype Li-O2 battery. The study on 3d orbital regulation of nanocrystals provides an innovative strategy for bifunctional electrocatalysts toward the practical application of metal-air batteries.

Wood-Structured Nanomaterials as Highly Efficient, Self-Standing Electrocatalysts for Water Splitting.

Electrocatalytic water splitting (EWS) driven by renewable energy is widely considered an environmentally friendly and sustainable approach for generating hydrogen (H2), an ideal energy carrier for the future. However, the efficiency and economic viability of large-scale water electrolysis depend on electrocatalysts that can efficiently accelerate the electrochemical reactions taking place at the two electrodes. Wood-derived nanomaterials are well-suited for serving as EWS catalysts because of their hierarchically porous structure with high surface area and low tortuosity, compositional tunability, cost-effectiveness, and self-standing integral electrode configuration. Here, recent advancements in the design and synthesis of wood-structured nanomaterials serving as advanced electrocatalysts for water splitting are summarized. First, the design principles and corresponding strategies toward highly effective wood-structured electrocatalysts (WSECs) are emphasized. Then, a comprehensive overview of current findings on WSECs, encompassing diverse structural designs and functionalities such as supported-metal nanoparticles (NPs), single-atom catalysts (SACs), metal compounds, and heterostructured electrocatalysts based on engineered wood hosts are presented. Subsequently, the application of these WSECs in various aspects of water splitting, including the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), overall water splitting (OWS), and hybrid water electrolysis (HWE) are explored. Finally, the prospects, challenges, and opportunities associated with the broad application of WSECs are briefly discussed. This review aims to provide a comprehensive understanding of the ongoing developments in water-splitting catalysts, along with outlining design principles for the future development of WSECs.

Periodic Defect Engineering of Iron-Nitrogen-Carbon Catalysts for Nitrate Electroreduction to Ammonia.

Iron-nitrogen-carbon single atom catalyst (SAC) is regarded as one of the promising electrocatalysts for NO3 - reduction reaction (NO3 RR) to NH3 due to its high activity and selectivity. However, synergistic effects of topological defects and FeN4 active moiety in Fe-N-C SAC have rarely been investigated. By performing density functional theory (DFT) calculations, 13 defective graphene FeN4 with 585, 484, and 5775 topological line defects are constructed, yielding 585-68-FeN4 with optimal NO3 RR catalytic activity, high selectivity, as well as robust anti-dissolution stability. The high NO3 RR activity on 585-68-FeN4 is well explained by the high valence state of Fe center as well as asymmetric charge distribution on FeN4 moiety influenced by 5- and 8-member rings. This DFT work provides theoretical guidance for engineering NO3 RR performance of iron-nitrogen-carbon catalysts by modulating periodic topological defects.

Single Ru Sites on Covalent Organic Framework-Coated Carbon Nanotubes for Highly Efficient Electrocatalytic Hydrogen Evolution.

Covalent organic frameworks (COFs) with precisely controllable structures and highly ordered porosity possess great potential as electrocatalysts for hydrogen evolution reaction (HER). However, the catalytic performance of pristine COFs is limited by the poor active sites and low electron transfer. Herein, to address these issues, the conductive carbon nanotubes (CNTs) are coated by a defined structure RuBpy(H2 O)(OH)Cl2 in bipyridine-based COF (TpBpy). And this composite with single site Ru incorporated can be used as HER electrocatalyst in alkaline conditions. A series of crucial issues are carefully discussed through experiments and density functional theory (DFT) calculations, such as the coordination structure of the atomically dispersion Ru ions, the catalytic mechanism of the embedded catalytic site, and the effect of COF and CNTs on the electrocatalytic properties. According to DFT calculations, the embedded single sites Ru act as catalytic sites for H2 generation. Benefitting from increasing the catalyst conductivity and the charge transfer, the as-prepared c-CNT-0.68@TpBpy-Ru shows an excellent HER overpotential of 112 mV at 10 mA cm-2 under alkaline conditions as well as an excellent durability up to 12 h, which is superior to that of most of the reported COFs electrocatalysts in alkaline solution.

New Insight into the Electronic Effect for Cu Porphyrin Catalysts in Electrocatalytic of CO2 into CH4.

Perturbation of the copper (Cu) active site by electron manipulation is a crucial factor in determining the activity and selectivity of electrochemical carbon dioxide (CO2 ) reduction reaction (e-CO2 RR) in Cu-based molecular catalysts. However, much ambiguity is present concerning their electronic structure-function relationships. Here, three molecular Cu-based porphyrin catalysts with different electron densities at the Cu active site, Cu tetrakis(4-methoxyphenyl)porphyrin (Cu─T(OMe)PP), Cu tetraphenylporphyrin (Cu─THPP), and Cu tetrakis(4-bromophenyl)porphyrin (Cu─TBrPP), are prepared. Although all three catalysts exhibit e-CO2 RR activity and the same reaction pathway, their performance is significantly affected by the electronic structure of the Cu site. Theoretical and experimental investigations verify that the conjugated effect of ─OCH3 and ─Br groups lowers the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbitals (LUMO) gap of Cu─T(OMe)PP and Cu─TBrPP, promoting faster electron transfer between Cu and CO2 , thereby improving their e-CO2 RR activity. Moreover, the high inductive effect of ─Br group reduces the electron density of Cu active site of Cu─TBrPP, facilitating the hydrolysis of the bound H2 O and thus creating a preferable local microenvironment, further enhancing the catalytic performance. This work provides new insights into the relationships between the substituent group characteristics with e-CO2 RR performance and is highly instructive for the design of efficient Cu-based e-CO2 RR electrocatalysts.

Pd "Kills Two Birds with One Stone" for the Synthesis of Catalyst: Dual Active Sites of Pd Triggers the Kinetics of O2 Electrocatalysis.

Noble metal-based catalyst, despite their exorbitant cost, are the only successful catalyst for bifunctional oxygen electrocatalysis owing to their capability to drive forward the reaction rate kinetically. Therefore, it is desirable to diminish the noble metal loading without any compromise in the catalyst performance. In this study, the aim to achieve two goals with one action via a single-step route to have ultra-low loading of Pd in the catalyst. The Pd is used as a catalyst for C─C bond formation followed by complexation reactions or vice versa, in conventional Suzuki-Miyaura cross-coupling (SMCC) reaction, which yields a Pd-based porous organic polymer. Interestingly, it is found that dispersed Pd nanocluster (PdNC ) is present together with Pd single atom doped into nanocarbon (Pd-NC) matrix in the catalyst (PdNC /Pd-NC800 ) that obtained after pyrolysis of the porous polymer. The catalyst exhibits remarkable bifunctional activity and durability towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Further, it is studied that the in situ attenuated total reflection infrared (ATR-IR) spectroscopy at different electrochemical potentials during ORR and OER to observe the reaction intermediates. The homemade zinc-air battery with the catalyst displayed great performance, establishing the significance of PdNC /Pd-NC800 as a bifunctional oxygen electrocatalyst.