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Facile synthesis of highly-dispersed Pt-based electrocatalysts on porous carbon supports with strong durability is extremely desirable for oxygen reduction reaction but remains challenging. The influence of pores in carbon supports on the stability and activity of catalysts is ambiguous and needs to be elucidated. Targeting this aim, herein, we prepared a series of carbon nanofibers with tunable pore diameter and specific surface area using the resorcinol-formaldehyde (RF) resins as a model system. Homogeneous composite precursors composed of RF resins and silica colloids were synthesized by the surfactant-assisted simultaneous polycondensation of RF resins and tetraethylorthosilicate (TEOS). The diameter of the pores induced by removal of silica could be controllable tailored through thermal treatment of the composite under various target temperatures. Pt 3 Co alloy nanoparticles loaded on the as-synthesized porous carbon nanofibers were prepared by an optimized wet-impregnation method. The experimental results indicated that the carbon nanofibers with pore size distribution focused on ∼1.27 nm and ∼2.34 nm provided the best stability without limiting current density decay, and negative shift of half-wave potential (E 1/2) and mass activity (MA) loss of Pt after 20000 potential cycles are relatively mild. Conversely, negative shift of 21 mV, 15 mV and 22 mV in E 1/2 and mass activity loss of 51.8%, 30.2% and 33.0% were observed for the Pt 3 Co nanoparticles supported on MC-60, MC-100 and MC-140 matrices which have pore size distribution focused on ∼2.73 nm, ∼2.73 nm as well as ∼4.66 nm, and ∼4.66 nm, respectively. This work demonstrates the importance of micropores and small mesopores for activity and long-term stability enhancement of carbon supported Pt-based electrocatalysts. Porous carbon nanofibers with tunable pore size distribution were synthesized by combining the surfactant-assisted simultaneous polycondensation of resorcinol-formaldehyde resins and TEOS with elaborate designed thermal treatment. Pt 3 Co nanoparticles loaded on the carbon with pore size distribution focuses on ∼1.27 nm and ∼2.34 nm provided the highest activity and best stability with no performance decay for ORR after 20000 potential cycles. [Display omitted] • Composite fibers of RF resins and Silica were synthesized by the developed surfactant-assisted polycondensation strategy. • Diameters of the mesopores in the synthesized carbon fibers could be controllable tuned. • Mesopores with diameter of ∼2.34 nm are efficient for boosting the stability of the carbon supported Pt 3 Co for the ORR. [ABSTRACT FROM AUTHOR]

Developing cost‐effective and sustainable acidic water oxidation catalysts requires significant advances in material design and in‐depth mechanism understanding for proton exchange membrane water electrolysis. Herein, we developed a single atom regulatory strategy to construct Co−Co dinuclear active sites (DASs) catalysts that atomically dispersed zirconium doped Co9S8/Co3O4 heterostructure. The X‐ray absorption fine structure elucidated the incorporation of Zr greatly facilitated the generation of Co−Co DASs layer with stretching of cobalt oxygen bond and S−Co−O heterogeneous grain boundaries interfaces, engineering attractive activity of significantly reduced overpotential of 75 mV at 10 mA cm−2, a breakthrough of 500 mA cm−2 high current density, and water splitting stability of 500 hours in acid, making it one of the best‐performing acid‐stable OER non‐noble metal materials. The optimized catalyst with interatomic Co−Co distance (ca. 2.80 Å) followed oxo‐oxo coupling mechanism that involved obvious oxygen bridges on dinuclear Co sites (1,090 cm−1), confirmed by in situ SR‐FTIR, XAFS and theoretical simulations. Furthermore, a major breakthrough of 120,000 mA g−1 high mass current density using the first reported noble metal‐free cobalt anode catalyst of Co−Co DASs/ZCC in PEM‐WE at 2.14 V was recorded. [ABSTRACT FROM AUTHOR]

The employment of different carbon supports during the fabrication of electrocatalysts has a considerable impact on the properties of loaded metal particles and even the stability of catalysts. Here, we present N-doped mesostructured hollow carbon spheres (HCSs) with radial mesoporous shells and a high specific surface area, that were synthesized by a one-pot and surfactant-free method. Pt nanoparticles of around 2 nm size were loaded on the HCS support as a highly stable electrocatalyst by the synergistic effect of nitrogen anchoring and partial pore confinement. The synthesized Pt/HCS catalyst possesses superior ORR activity compared to commercial Pt/C, with a half-wave potential of 0.906 V and mass activity of 0.266 A mgPt−1. Remarkably, the mass activity of Pt/HCS only declined by 13% after an accelerated durability test of 30 000 cycles, whereas that of Pt/C dropped by 76%. These results indicate that Pt/HCS will be a promising catalyst for the cathodic oxygen reduction of PEMFCs. [ABSTRACT FROM AUTHOR]

Metal‐nitrogen‐carbon catalysts, as promising alternative to platinum‐based catalysts for oxygen reduction reaction (ORR), are still highly expected to achieve better performance by modulating the composition and spatial structure of active site. Herein, we constructed the non‐planar nest‐like [Fe2S2] cluster sites in N‐doped carbon plane. Adjacent double Fe atoms effectively weaken the O−O bond by forming a peroxide bridge‐like adsorption configuration, and the introduction of S atoms breaks the planar coordination of Fe resulting in greater structural deformation tension, lower spin state, and downward shifted Fe d‐band center, which together facilitate the release of OH* intermediate. Hence, the non‐planar [Fe2S2] cluster catalyst, with a half‐wave potential of 0.92 V, displays superior ORR activity than that of planar [FeN4] or [Fe2N6]. This work provides insights into the co‐regulation of atomic composition and spatial configuration for efficient oxygen reduction catalysis. [ABSTRACT FROM AUTHOR]

Regulating the coordination environment of transition-metal based materials in the axial direction with heteroatoms has shown great potential in boosting the oxygen reduction reaction (ORR). The coordination configuration and the regulation method are pivotal and elusive. Here, we report a combined strategy of matrix-activization and controlled-induction to modify the CoN4 site by axial coordination of Co—S (Co1N4-S1), which was validated by the aberration-corrected electron microscopy and X-ray absorption fine structure analysis. The optimal Co1N4-S1 exhibits an excellent alkaline ORR activity, according to the half-wave potential (0.897 V vs. reversible hydrogen electrode (RHE)), Tafel slope (24.67 mV/dec), and kinetic current density. Moreover, the Co1N4-S1 based Zn-air battery displays a high power density of 187.55 mW/cm2 and an outstanding charge—discharge cycling stability for 160 h, demonstrating the promising application potential. Theoretical calculations indicate that the better regulation of CoN4 on electronic structure and thus the highly efficient ORR performance can be achieved by axial Co—S. [ABSTRACT FROM AUTHOR]

Fine‐tuning single‐atom catalysts (SACs) to surpass their activity limit remains challenging at their atomic scale. Herein, we exploit p‐type semiconducting character of SACs having a metal center coordinated to nitrogen donors (MeNx) and rectify their local charge density by an n‐type semiconductor support. With iron phthalocyanine (FePc) as a model SAC, introducing an n‐type gallium monosulfide that features a low work function generates a space‐charged region across the junction interface, and causes distortion of the FeN4 moiety and spin‐state transition in the FeII center. This catalyst shows an over two‐fold higher specific oxygen‐reduction activity than that of pristine FePc. We further employ three other n‐type metal chalcogenides of varying work function as supports, and discover a linear correlation between the activities of the supported FeN4 and the rectification degrees, which clearly indicates that SACs can be continuously tuned by this rectification strategy. [ABSTRACT FROM AUTHOR]

Atomically dispersed sites anchored on small oxide clusters are attractive new catalytic materials. Herein, we demonstrate an electrical pulse approach to synthesize atomically dispersed Pt on various oxide clusters in one step with nitrogen‐doped carbon as the support (Pt1−MOx/CN). As a proof‐of‐concept application, Pt1−FeOx/CN is shown to exhibit high activity for oxygen reduction reaction (ORR) with a half‐wave potential of 0.94 V vs RHE, in contrast to the poor catalytic performance of atomically dispersed Pt on large Fe2O3 nanoparticles. Our work has revealed that, by tuning the size of the iron oxide down to the cluster regime, an optimal OH* adsorption strength for ORR is achieved on Pt1−FeOx/CN due to the regulation of Pt−O bonds. The unique structure and high catalytic performance of Pt1−FeOx/CN enable the Zinc‐Air batteries an excellent performance at ultralow temperature of −40 °C with a high peak power density of 45.1 mW cm−2 and remarkable cycling stability up to 120 h. [ABSTRACT FROM AUTHOR]

The in‐depth understanding of local atomic environment–property relationships of p‐block metal single‐atom catalysts toward the 2 e− oxygen reduction reaction (ORR) has rarely been reported. Here, guided by first‐principles calculations, we develop a heteroatom‐modified In‐based metal–organic framework‐assisted approach to accurately synthesize an optimal catalyst, in which single In atoms are anchored by combined N,S‐dual first coordination and B second coordination supported by the hollow carbon rods (In SAs/NSBC). The In SAs/NSBC catalyst exhibits a high H2O2 selectivity of above 95 % in a wide range of pH. Furthermore, the In SAs/NSBC‐modified natural air diffusion electrode exhibits an unprecedented production rate of 6.49 mol peroxide gcatalyst−1 h−1 in 0.1 M KOH electrolyte and 6.71 mol peroxide gcatalyst−1 h−1 in 0.1 M PBS electrolyte. This strategy enables the design of next‐generation high‐performance single‐atom materials, and provides practical guidance for H2O2 electrosynthesis. [ABSTRACT FROM AUTHOR]

Exploring nonprecious and highly efficient electrocatalysts for the oxygen reduction reaction (ORR) is critically important for the large scale application of metal–air batteries. Herein, iron oxides and Fe–N4 moieties anchored on nitrogen doped porous carbon nanosheets (Fe2O3@C/FeNC-900) are designed and constructed by coordinating egg white with iron ions, followed by nitrogen doping and one-step pyrolysis under nitrogen atmosphere. The synthesis procedure, without the need of using any toxic materials or acid leaching post-treatment, is convenient and environmentally friendly. The unique structure of Fe2O3@C/FeNC-900 with atomically dispersed Fe–N4 moieties and iron oxide nanoparticles confined in sheet-like porous carbon is revealed using XRD, TEM, XPS and X-ray absorption fine structure spectroscopy (XAFS). The multiple active centers and strong synergistic effects endow Fe2O3@C/FeNC-900 with excellent ORR catalysis performance in alkaline electrolyte. It exhibits a positive half-wave potential of 0.89 V in 0.1 M KOH and excellent long-term stability. Beyond that, the zinc–air battery (ZAB) using Fe2O3@C/FeNC-900 as the cathode material shows excellent electrochemical performance and remarkable cycling performance. This research provides a facile and environmentally friendly strategy for the synthesis of nonprecious electrocatalysts beneficial to practical metal–air battery applications. [ABSTRACT FROM AUTHOR]

The modulation effect has been widely investigated to tune the electronic state of single‐atomic M‐N‐C catalysts to enhance the activity of oxygen reduction reaction (ORR). However, the in‐depth study of modulation effect is rarely reported for the isolated dual‐atomic metal sites. Now, the catalytic activities of Fe‐N4 moiety can be enhanced by the adjacent Pt‐N4 moiety through the modulation effect, in which the Pt‐N4 acts as the modulator to tune the 3d electronic orbitals of Fe‐N4 active site and optimize ORR activity. Inspired by this principle, we design and synthesize the electrocatalyst that comprises isolated Fe‐N4/Pt‐N4 moieties dispersed in the nitrogen‐doped carbon matrix (Fe‐N4/Pt‐N4@NC) and exhibits a half‐wave potential of 0.93 V vs. RHE and negligible activity degradation (ΔE1/2=8 mV) after 10000 cycles in 0.1 M KOH. We also demonstrate that the modulation effect is not effective for optimizing the ORR performances of Co‐N4/Pt‐N4 and Mn‐N4/Pt‐N4 systems. [ABSTRACT FROM AUTHOR]

Demonstrated here is the correlation between atomic configuration induced electronic density of single‐atom Co active sites and oxygen reduction reaction (ORR) performance by combining density‐functional theory (DFT) calculations and electrochemical analysis. Guided by DFT calculations, a MOF‐derived Co single‐atom catalyst with the optimal Co1‐N3PS active moiety incorporated in a hollow carbon polyhedron (Co1‐N3PS/HC) was designed and synthesized. Co1‐N3PS/HC exhibits outstanding alkaline ORR activity with a half‐wave potential of 0.920 V and superior ORR kinetics with record‐level kinetic current density and an ultralow Tafel slope of 31 mV dec−1, exceeding that of Pt/C and almost all non‐precious ORR electrocatalysts. In acidic media the ORR kinetics of Co1‐N3PS/HC still surpasses that of Pt/C. This work offers atomic‐level insight into the relationship between electronic density of the active site and catalytic properties, promoting rational design of efficient catalysts. [ABSTRACT FROM AUTHOR]

For electrocatalysts for the hydrogen evolution reaction (HER), encapsulating transition metal phosphides (TMPs) into nitrogen‐doped carbon materials has been known as an effective strategy to elevate the activity and stability. Yet still, it remains unclear how the TMPs work synergistically with the N‐doped support, and which N configuration (pyridinic N, pyrrolic N, or graphitic N) contributes predominantly to the synergy. Here we present a HER electrocatalyst (denoted as MoP@NCHSs) comprising MoP nanoparticles encapsulated in N‐doped carbon hollow spheres, which displays excellent activity and stability for HER in alkaline media. Results of experimental investigations and theoretical calculations indicate that the synergy between MoP and the pyridinic N can most effectively promote the HER in alkaline media. [ABSTRACT FROM AUTHOR]

Electrocatalysis plays a central role in clean energy conversion, enabling a number of processes for future sustainable technologies. Atomic site electrocatalysts (ASCs), including single-atomic site catalysts (SASCs) and diatomic site catalysis (DASCs), are being pursued as economical alternatives to noble-metal-based catalysts for these reactions by virtue of their exceptionally high atom utilization efficiencies, well-defined active sites and high selectivities. In this review, we start from a systematic review on the fabrication routes of ASCs followed by an overview of some new and effective characterization methods to precisely probe the atomic structure. Then we give a comprehensive summary on the current advances in some typical clean energy reactions: water splitting, including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER); oxygen reduction reaction (ORR), including selective 4e− – ORR toward H2O/OH− and 2e− – ORR toward H2O2/HO2−; selective electrooxidation of formic acid, methanol and ethanol (FAOR, MOR and EOR). At the end of this paper, we present a brief conclusion, and discuss the challenges and opportunities on the further development of more selective, active, stable and less expensive ASCs. [ABSTRACT FROM AUTHOR]

We report carbon nanotube-encapsulated cobalt as an efficient oxygen reduction electrocatalyst (onset potential of 0.94 V and half-potential of 0.84 V). Calculation results firstly reveal that Co protected by graphitic-N-doped carbon holds more negative charge (−1.22 eV) and has an energy barrier (0.56 eV) lower than that of pyridinic-N-doped carbon (−1.11 eV; 0.78 eV), which is responsible for the ORR activity. The corresponding Zn–air batteries deliver an excellent gravimetric energy density of 837 W h kg−1. [ABSTRACT FROM AUTHOR]

We developed a strategy based on coordination polymer to synthesize singleatom site Fe/N and S-codoped hierarchical porous carbon (Fe1/N,S-PC). The as-obtained Fe1/N,S-PC exhibited superior oxygen reduction reaction (ORR) performance with a half-wave potential (E1/2, 0.904 V vs. RHE) that was better than that of commercial Pt/C (E1/2, 0.86 V vs. RHE), single-atom site Fe/N-doped hierarchical porous carbon (Fe1/N-PC) without S-doped (E1/2, 0.85 V vs. RHE), and many other nonprecious metal catalysts in alkaline medium. Moreover, the Fe1/N,S-PC revealed high methanol tolerance and firm stability. The excellent electrocatalytic activity of Fe1/N,S-PC is attributed to the synergistic effects from the atomically dispersed porphyrin-like Fe-N4 active sites, the heteroatom codoping (N and S), and the hierarchical porous structure in the carbon materials. The calculation based on density functional theory further indicates that the catalytic performance of Fe1/N,S-PC is better than that of Fe1/N-PC owing to the sulfur doping that yielded different rate-determining steps. [ABSTRACT FROM AUTHOR]

We successfully prepared Fe and Co isolated single atoms on metal–organic framework derived nitrogen-doped carbon (FeCo-ISAs/CN) by an adsorption–calcination strategy. The obtained FeCo-ISAs/CN exhibited top-level catalytic reactivity for the alkaline oxygen reduction reaction (ORR) with a half-wave potential of 0.920 V, which was 70 mV more positive than that of commercial Pt/C. Moreover, the catalyst was durable and showed negligible activity decay in the alkaline ORR during 5000 voltage cycles. [ABSTRACT FROM AUTHOR]

The development of low-cost, efficient, and stable electrocatalysts for the oxygen reduction reaction (ORR) is desirable but remains a great challenge. Herein, we made a highly reactive and stable isolated single-atom Fe/N-doped porous carbon (ISA Fe/CN) catalyst with Fe loading up to 2.16 wt %. The catalyst showed excellent ORR performance with a half-wave potential ( E1/2) of 0.900 V, which outperformed commercial Pt/C and most non-precious-metal catalysts reported to date. Besides exceptionally high kinetic current density ( Jk) of 37.83 mV cm−2 at 0.85 V, it also had a good methanol tolerance and outstanding stability. Experiments demonstrated that maintaining the Fe as isolated atoms and incorporating nitrogen was essential to deliver the high performance. First principle calculations further attributed the high reactivity to the high efficiency of the single Fe atoms in transporting electrons to the adsorbed OH species. [ABSTRACT FROM AUTHOR]

A new strategy for achieving stable Co single atoms (SAs) on nitrogen-doped porous carbon with high metal loading over 4 wt % is reported. The strategy is based on a pyrolysis process of predesigned bimetallic Zn/Co metal-organic frameworks, during which Co can be reduced by carbonization of the organic linker and Zn is selectively evaporated away at high temperatures above 800 °C. The spherical aberration correction electron microscopy and extended X-ray absorption fine structure measurements both confirm the atomic dispersion of Co atoms stabilized by as-generated N-doped porous carbon. Surprisingly, the obtained Co-N x single sites exhibit superior ORR performance with a half-wave potential (0.881 V) that is more positive than commercial Pt/C (0.811 V) and most reported non-precious metal catalysts. Durability tests revealed that the Co single atoms exhibit outstanding chemical stability during electrocatalysis and thermal stability that resists sintering at 900 °C. Our findings open up a new routine for general and practical synthesis of a variety of materials bearing single atoms, which could facilitate new discoveries at the atomic scale in condensed materials. [ABSTRACT FROM AUTHOR]

Correction to: I Nature Communications i https://doi.org/10.1038/s41467-018-07850-2, published online 21 December 2018. These authors contributed equally: Yuanjun Chen, Shufang Ji, Shu Zhao. [Extracted from the article]

In recent years, various non-precious metal electrocatalysts for the oxygen reduction reaction (ORR) have been extensively investigated. The development of an efficient and simple method to synthesize non-precious metal catalysts with ORR activity superior to that of Pt is extremely significant for large-scale applications of fuel cells. Here, we develop a facile, low-cost, and large-scale synthesis method for uniform nitrogen-doped (N-doped) bamboo-like CNTs (NBCNT) with Co nanoparticles encapsulated at the tips by annealing a mixture of cobalt acetate and melamine. The uniform NBCNT shows better ORR catalytic activity and higher stability in alkaline solutions as compared with commercial Pt/C and comparable catalytic activity to Pt/C in acidic media. NBCNTs exhibit outstanding ORR catalytic activity due to high defect density, uniform bamboo-like structure, and the synergistic effect between the Co nanoparticles and protective graphitic layers. This facile method to synthesize catalysts, which is amenable to the large-scale commercialization of fuel cells, will open a new avenue for the development of low-cost and high-performance ORR catalysts to replace Pt-based catalysts for applications in energy conversion. [ABSTRACT FROM AUTHOR]

The reasonable design and construction of single-atom electrocatalysts with low-cost and excellent intrinsic activity for oxygen reduction reaction (ORR) is indispensable in metal-air batteries. Herein, a facile isolation anchoring strategy was reported for in situ formation of porous N-doped carbon catalysts (Fe 1 /NC) rich in Fe single atoms. The d -glucose, zinc gluconate and N-rich histidine were deployed as spatial isolation agents and anchoring agents to inhibit iron atom aggregation during the high-temperature pyrolysis. The as-synthesized Fe 1 /NC catalyst shows remarkable stability and superior ORR electrocatalytic activity under both alkaline and acidic conditions owing to highly dispersed Fe–N 4 sites, especially with a half-wave potential up to 0.91 V in 0.1 M KOH, exceeding 60 mV compared with Pt/C. Notably, the Fe 1 /NC-based Zn-air battery exhibits maximal power density of 164 mW cm−2, large specific capacities of 769 mA h g Zn −1, excellent cycle stability over 300 h, and great potential in renewable energy conversion electronics. A facile isolation anchoring strategy was reported to synthesize the Fe single-atom electrocatalyst that exhibits excellent ORR catalytic efficiency and long-term stability in both three electrodes system and zinc-air battery due to the abundant Fe–N 4 active sites. [Display omitted] • A facile isolation anchoring strategy was reported to prepare Fe single-atom electrocatalyst. • d -glucose, zinc gluconate and N-rich histidine were deployed as spatial isolation and anchoring agents. • The electrocatalysts exhibit superior ORR performance due to the abundant Fe–N 4 active sites. • The Zn-air battery assembled with Fe 1 /NC displays a high discharge specific capacity and excellent cyclic stability. [ABSTRACT FROM AUTHOR]

Correction for ‘Isolated Fe and Co dual active sites on nitrogen-doped carbon for a highly efficient oxygen reduction reaction’ by Diyang Zhang et al., Chem. Commun., 2018, DOI: URL10.1039/c8cc00988k/URL. [ABSTRACT FROM AUTHOR]

The development of highly active, cheap and robust oxygen reduction reaction (ORR) electrocatalysts to replace precious metal platinum is extremely urgent and challenging for renewable energy devices. Herein we report a novel, green and especially facile hydrogel strategy to construct N and B co-doped nanocarbon embedded with Co-based nanoparticles as an efficient non-precious ORR catalyst. The agarose hydrogel provides a general host matrix to achieve a homogeneous distribution of key precursory components including cobalt (II) acetate and buffer salts, which, upon freeze-drying and carbonization, produces the highly active ORR catalyst. The gel buffer containing Tris base, boric acid and ethylenediaminetetraacetic acid, commonly adopted for pH and ionic strength control, plays distinctively different roles here. These include a green precursor for N- and B-doping, a salt porogen and a Co2+ chelating agent, all contributing to the excellent ORR activity. This hydrogel-based process is potentially generalizable for many other catalytic materials. [ABSTRACT FROM AUTHOR]

A novel in situ strategy to embed Co 9 S 8 nanoparticles into nitrogen and sulfur codoped hollow porous carbon (Co 9 S 8 @N-S-HPC) is achieved. The Co 9 S 8 @N-S-HPC can be used an efficient catalyst for both ORR and HER. The unique nanostructure and synergistic interactions between Co 9 S 8 and N-S-HPC play a crucial role to improve the electrocatalytic performance. • Co 9 S 8 @N-S-HPC is fabricated using a novel in situ formation approach. • Co 9 S 8 @N-S-HPC shows excellent electrocatalytic performance toward ORR and HER. • Synergistic effect of Co 9 S 8 and N-S-HPC improves the electrocatalytic performance. The oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) are critical processes for many energy conversion technologies, where efficient catalyst plays a key role in these reactions. Here we report a novel in situ strategy to embed Co 9 S 8 nanoparticles (NPs) into nitrogen and sulfur codoped hollow porous carbon (Co 9 S 8 @N-S-HPC). In this strategy, the ZIF-8 surface is firstly decorated by cobalt thiourea, and then coated with a shell of polymeric resorcinol-formaldehyde, followed by a high temperature pyrolysis treatment. The resulting Co 9 S 8 @N-S-HPC shows comparable catalytic activity for ORR compared with commercial 20 wt% Pt/C catalyst and superior long-term stability under alkaline conditions. Simultaneously, Co 9 S 8 @N-S-HPC also exhibits an excellent HER activity with low onset overpotential of 68 mV, a small Tafel slope of 78 mV per decade and a long-term durability in alkaline medium. First-principles calculations reveal that Co 9 S 8 particle can anchor in N-S-HPC via a Co-S bond and enhance the binding of Co 9 S 8 and N-S-HPC. The N-S-HPC can affect the electronic structure of supported Co 9 S 8 strongly. The combined experimental and theoretical investigation show the outstanding ORR and HER performances of Co 9 S 8 @N-S-HPC are attributed to its unique nanostructure and synergistic interactions between Co 9 S 8 NPs and N-S-HPC. [ABSTRACT FROM AUTHOR]