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• Atomically dispersed Fe and Cu sites with two-N-bridged decorated N-doped porous carbon is synthesized. • The fine structure of Fe 1 Cu 1 -NC is characterized by AC-HAADF-STEM and XAFS. • The Fe 1 Cu 1 -NC catalyst exhibits a comparable ORR activity to Pt/C with excellent methanol tolerance and stability. • DFT calculation indicates that the synergistic effect between Fe and Cu is preferable for modulating ORR activity. The sluggish reaction kinetics of oxygen reduction reactions (ORR), combined with a long-standing dependence on expensive and unstable platinum-based catalysts, has significantly hindered the progress of sustainable energy solutions. Here, we have developed an atomically dispersed bimetallic FeCu-loaded N-doped porous carbon (Fe 1 Cu 1 -NC) catalyst for remarkable ORR efficiency. X-ray absorption fine structure (XAFS) analysis accurately determines that the coordination state of atomically dispersed Fe-Cu sites is a two-N-bridged with N 6 ligand. Fe 1 Cu 1 -NC has demonstrated superior ORR performance in alkaline environments when compared to commercial Pt/C catalysts. Notably, Fe 1 Cu 1 -NC exhibits a higher power density and specific capacity than Pt/C in zinc-air batteries. Density functional theory (DFT) calculations further confirm that the improved performance is due to the combined action of Cu and Fe single atoms, which results in a negative shift of the d -band center energy of Fe and facilitates activation of ORR intermediates. Atomically dispersed dual-metal with two-N-bridged FeCu-N 6 sites can lead to a negative shift in the d -band center of Fe, resulting in a weakening of the adsorption strength of intermediate species and enhancing the ORR performance in comparison to Pt/C. [Display omitted] [ABSTRACT FROM AUTHOR]

• Ageing of supercapacitors with two different carbons is studied through different methods. • two different ageing mechanism are observed because of the differences on carbons (porosity, surface state, etc). • Polymerization film on YP50F positive electrode, more defect density for CMK3 positive electrode. Understanding the ageing mechanisms of porous carbon electrodes used in electrochemical double layers supercapacitors (EDLCs) is of high importance to improve their lifetime. In this work, we studied ageing of two different porous carbons with different pore size distribution and surface functionalities in 1.5 M tetraethyl ammonium tetrafluoroborate (Et 4 NBF 4) in acetonitrile (AN) electrolyte. The combination of Raman spectroscopy, thermogravimetric analysis (TGA), gas sorption and electrochemical impedance spectroscopy techniques allowed us to identify two different behaviors depending on the porous carbon used. A microporous carbon experiences an ionic/electronic resistance increase leading to a capacitance fall off upon cycling, associated with pore clogging. This resulted from the electrolyte degradation taking place at the positive electrode combined with porous carbon oxidation. Differently, only an increase of the series resistance was observed for the mesoporous carbon tested, following the creation of defects at the positive carbon electrode. [ABSTRACT FROM AUTHOR]

Confining the dissolution and diffusion of polysulfide is considered a key factor in the realization of high-performance lithium-sulfur battery. Here, we report a polydopamine (pDA) coated sulfur-carbon composite with a unique hierarchical tower-like structure (S-HTC@pDA) for lithium sulfur cathode. The internal layer by layer structure is capable of uniformly dispersing of sulfur, providing a continuous electronic conductive path and shortening the Li+ transport distance, while the external pDA coating can inhibit the diffusion of polysulfide. Benefited from the smart design, the S-HTC@pDA electrode achieved an excellent cycling stability, realizing a high discharge capacity of 916 mAh g−1 at the first cycle and a capacity retention of 79.4% after 500 cycles at 1 C. Therefore, this work provides a new concept in structure design for high performance lithium sulfur cathodes. Here, we report a polydopamine (pDA) coated sulfur-carbon composite with a unique hierarchical tower-like structure (S-HTC@pDA) for lithium sulfur cathode. The internal layer by layer structure is capable of uniformly dispersing of sulfur, providing a continuous electronic conductive path and shortening the Li+ transport distance, while the external pDA coating can inhibit the diffusion of polysulfide. Image 1 • Polydopamine coated sulfur-carbon composite with a unique hierarchical tower-like structure has been fabricated. • The unique structure of layer-by-layer inner space with pDA coating outside could improve the performance of Li-S cathodes. • The S-HTC@pDA electrode exhibits excellent cycling stability. [ABSTRACT FROM AUTHOR]

Biowaste, derived from cooking-oven-produced carbon nanoparticles (WCP), are incorporated into polyaniline (PANI) via in-situ chemical oxidative polymerization to achieve excellent electrochemical properties for application in supercapacitors. The WCP-PANI composite electrodes have shown high-performance charge storage, due to combinatorial effect of electrical double layer capacitance from WCP and pseudocapacitance from PANI. With increase in the WCP percolation, work function of PANI is increased, which improves the charge-trapping capabilities of composites. For such distinct charge-trapping mechanism, areal capacitance of the composite microelectrode remains near-constant with increase in scan rate or current density. This indicates the suppression of diffusion limitations at higher scan rates to considerably enhance the rate capability. Also, with increasing polymerization time, strong interaction in this conjugated system greatly improves the charge-transfer reaction between PANI and WCP. The areal capacitance of the composite electrode is found to increase more than 600 times over pure PANI electrode. Moreover, energy-power performance of the microelectrode reveals almost 550% increment in the power density with a mere 1% decrement in energy density. Such rationally synthesized WCP-PANI composite electrodes using biowaste carbon nanomaterials, provide opportunities for the development of next-generation green-supercapacitors with improved energy storage performance. Image 1 • Low cost sustainable economy: "reduce, reuse and recycle" of waste carbons are main three building factors for this report. • A novel charge-trapping phenomenon of PANI-WCP: diffusion limitation at higher scan-rate/current-densities is suppressed. • An unusual increment in areal capacitance : the reason of which is explained for the first time by a physico-chemical model. • Huge increment of energy power efficiency: almost 550% increase in power density with a mere 1% decrease in energy density. [ABSTRACT FROM AUTHOR]

Abstract This work shows the potential application of carbon materials prepared by three different ionic liquid-based methods, using 1-butyl-3-methylimidazolium methanesulfonate [bmim][MeSO 3 ], for electrochemical supercapacitors. The effects of [bmim][MeSO 3 ] on morphology, texture and surface chemistry of prepared materials has been explored by SEM/TEM, N 2 /CO 2 adsorption measurements and XPS. The results indicate the possibility of synthesis of carbon materials with tunable physicochemical properties using ionic liquid based methods. The charge storage behavior of all materials was studied in three different pH aqueous electrolytes. The pseudocapacitive and double layer contributions were estimated and discussed from the aspect of the textural changes and the changes of the chemical composition of surface functional groups containing heteroatoms. C O type functional groups, with the contribution of COOH groups, were found to be responsible for a different amount of charge, which could be stored in alkaline and acidic electrolytic solution. The material prepared by direct carbonization of [bmim][MeSO 3 ], showed the best electrochemical performance in alkaline electrolyte with a capacitance of 187 F g−1 at 5 mV s−1 (or 148 F g−1 at 1 A g−1), due to the contribution of both electric-double layer capacitance and pseudocapacitance which arises from oxygen, nitrogen and sulfur functional groups. Graphical abstract Image 1 Highlights • Carbon materials were synthesized using new ionic liquid (IL) based methods. • Charge storage behavior in three pH-different electrolytes was compared. • Double layer and pseudocapacitance were separated and compared. • C O and COOH were found to be responsible for different charge storage. • Carbonized IL showed the highest capacitance due to contribution of N and S groups. [ABSTRACT FROM AUTHOR]

Abstract SnO x is considered as a promising anode candidate for lithium-ion batteries, but suffers from the low electrical conductivity and severe volume expansion during cycling. To solve these issues, we develop a simple and facile process of incipient wetness impregnation followed by pyrolysis gel molecules to prepare SnO x /mesoporous carbon nanofiber arrays, SnO x /graphene, SnO x /carbon nanotubes and SnO x /three-dimensionally ordered macroporous carbon materials. Notably, SnO x nanoparticles about 5 nm are prepared by a nonaqueous sol-gel method. We also explore the effect of different morphologies and pore structures of four carbon substrates on the electrochemical performance of the composites. Benefiting from the small size of SnO x nanoparticles and the synergistic effect between SnO x and the different carbon matrix materials, SnO x -Carbon electrode materials display excellent rate capability and cycle stability. SnO x /mesoporous carbon nanofiber arrays exhibits the best rate (522 mA h g−1 at 2000 mA g−1) and cycling performances (1327 mA h g−1 after 200 cycles at 100 mA g−1). The superior electrochemical performance, facile synthesized method and low cost of the Sn-based materials exhibit promising application for SnO x /mesoporous carbon nanofiber arrays as anode materials for next-generation lithium-ion batteries. Furthermore, the ex situ X-ray photoelectron spectroscopy studies on this electrode material under different states suggest that the Sn and Li 2 O could reversibly react to form SnO x during the charging process. [ABSTRACT FROM AUTHOR]

Abstract Increasing the specific capacity and cycle life of graphitic carbon anodes is crucial for realizing high-performance lithium ion batteries. Herein, we introduce a new class of graphitic carbon anodes comprising highly ordered three-dimensional nanostructures decorated with SnO 2 nanoparticles. The inch-scale, nanostructured graphitic carbon matrices are prepared by supported pyrolysis of epoxy templates patterned by advanced optical lithography. During the subsequent decoration process, the SnO 2 nanoparticles are densely formed on the matrix without agglomeration since the periodic nanostructured matrix provides a homogeneous site for nucleation and growth. The surface coverage of the decorated SnO 2 nanoparticles and the mass relative to the graphitic carbon are >80% and ∼50 wt%, respectively. The resulting nanostructured C/SnO 2 composite monoliths can be assembled solely into LIB coin cells without the aid of binders and conducting agents. The achieved specific capacity and retention are 692 mAh g−1 and 87.31% (at 70th cycle), respectively, which is superior to those of nanostructured carbon anodes prepared in a similar way. [ABSTRACT FROM AUTHOR]

Integrating polyaniline (PANI) with different dimensional carbon materials is considered as a promising strategy to solve the disadvantages of PANI electrodes, such as low rate capability and poor cyclic stability. In this work, a novel layer-by-layer sandwiched graphene/PANI nanorods/carbon nanotubes (G/PANI/CNTs) heterostructure has been synthesized. The morphology of the heterostructures has been characterized by XRD, Raman spectroscopy, N 2 adsorption-desorption, XPS, FESEM and TEM. The obtained new layer-by-layer sandwiched heterostructures exhibit intimate interface contacts, fully network-structured CNTs coating, dual physical supports and synergistic effects, which can effective host the electrochemical properties of PANI with the electrolyte and restrain the volumetric changes of PANI. As a result, the electrodes exhibit high specific capacitance (638 F g -1  at 0.5 A g −1 ), good rate capability (88.2% retention from 0.5 A g −1 to 10 A g −1 ) and long cycle stability (93% of the initial specific capacitance after 2000 cycles) when the amount of CNTs is 2 mg. Moreover, a possible mechanism for good performance of the layer-by-layer sandwiched heterostructures has been systematically studied. We believe that this strategy will open up an avenue for the rational design of sandwich structured electrodes for high performance supercapacitors and other electronic devices. [ABSTRACT FROM AUTHOR]

A negative electrode material of nano vanadium nitride/interconnected porous carbon (Nano-VN/IPC) is fabricated via a novel method combining surface-initiated electrochemical mediated ATRP and heat-treatment process. The structural and composition characterization display that a low crystallinity of VN nanoparticles is obtained, which distributes uniformly in the interconnected pores of the carbon scaffold materials. The high-distribution of nano-VN particles in the interconnected pores significantly enhances the usage efficiency of the electrochemistry-active materials to ensure the high electrochemical performance of the electrode materials. The interconnected pore structure is convenient for diffusion and transfer of electrolyte ions during charging-discharging process. The Nano-VN/IPC electrodes exhibit a high specific capacitance of 284.0 F/g at 0.5 A/g in 2 M KOH aqueous electrolyte with a low resistance and good rate capability. In addition, an asymmetric supercapacitor is assembled with Ni(OH) 2 and Nano-VN/IPC electrodes as the positive and negative electrodes. The device presents a high specific capacitance of 122 F/g at the current density of 0.5 A/g, and when the current density increases to 5 A/g the capacitance still remains 70 F/g. Remarkably, the device delivers an ultrahigh power density of 35.6 Wh/kg at a power density of 362.5 W/kg. [ABSTRACT FROM AUTHOR]

• The MnO 2 loaded flower-like carbon microsphere composite electrodes were prepared. • The electrode with core-shell structures exhibited superior capacitive performance. • The assembled supercapacitor can light a LED successfully more than three minutes. Herein, the flower-like carbon microspheres derived from polyimides(PI) are prepared by solvothermal method and carbonization. Then, the MnO 2 loaded carbon microflowers are obtained by hydrothermal process. The influences of mass ratio of carbon microflowers to KMnO 4 , hydrothermal time and temperature on the electrochemical behaviors of the composites are investigated. After optimizing conditions, the MC(1:3)-80–8 exhibits a higher specific capacity of 145.40 mAh g−1 (523.43 F g−1) at 0.5 A g−1. Furthermore, the optimum composite electrodes are fabricated into a symmetric supercapacitor(SC), which attains an energy density of 16.7 Wh kg−1, coupled with a power density of 193 W kg−1. The SC exhibits a long-time cycle stability of 93.5% after 20,000 charge and discharge cycles at 1 A g−1. Besides, only one SC can successfully light a LED more than three minutes. Therefore, the MnO 2 loaded flower-like carbon microsphere composites are one kind of valuable candidates for electrode materials of supercapacitors. [ABSTRACT FROM AUTHOR]

A novel strategy for the development of high energy density supercapacitors (SC) is explored. The new devices contain two electrolytes that are different in nature, an aqueous electrolyte in one half-cell and an ionic liquid in the other. These systems, referred to as biliquid SCs, make it possible to combine the best electrode/electrolyte in terms of individual electrode capacitance and cathodic/anodic stability limits. Furthermore, other asymmetries that combine different electrodes, electrolytes and storage mechanisms can be incorporated. Synchronous cyclic chronopotenciometry was used to monitor the performance of these novel complex systems. It is expected that this approach will help scientists working in this field to develop new devices that overcome the energy density limitations of current SCs, thereby extending the scope of their application. [ABSTRACT FROM AUTHOR]

Manganese oxides are known as active catalysts for the oxygen reduction reaction (ORR) in alkaline media. Being poor electronic conductors, for electrochemical applications, most of Mn oxides are either mixed with or supported on carbon materials, which impart electronic conductivity to the composite electrodes. A number of recent publications reported an immense influence of carbon materials on the electrocatalytic activity of transition metal oxides in the ORR. To better understand the role of carbon, in this work we utilize a wide variety of carbon materials and investigate the ORR on Mn 2 O 3 /carbon composites combining experiment with kinetic modeling. Such an approach allows us to discriminate the contribution of carbon in the ORR activity of composites, underscoring its positive role in improving the oxide utilization, and acting as the ORR co-catalyst, but also its negative role in competing for the adsorption of O 2 . By juxtaposing the electrocatalytic activity with the structural and morphological characteristics carbon materials, we propose some rules of thumb for choosing carbons necessary for creating efficient oxide/carbon ORR electrocatalysts. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO 2 using electricity from renewable sources is emerging as a promising approach for reducing global CO 2 emissions and converting CO 2 into useful chemicals. Here, a nitrogen–doped porous carbon material is proposed to electrocatalytically reduce CO 2 to CO with high activity, selectivity and superior durability. The material is synthesized by a facile one–step pyrolysis approach using biomass, namely wheat flour, and KOH as starting materials. The resulting materials show high surface area with hierarchical porous structures, and the nitrogen content and functional species can be controlled to some extent via the pyrolysis temperature. The catalyst exhibits a maximum faradaic efficiency of 83.7% and a partial current density of CO of 6.6 mA cm −2 at an overpotential of 0.71 V in aqueous bicarbonate medium. Moreover, it also demonstrates superior long–term durability with trivial loss of activity and selectivity. Mechanistic study indicates that the pyridinic nitrogen is responsible for the high catalytic activity. [ABSTRACT FROM AUTHOR]

Carbon materials have been widely applied in the energy storage devices, however, the preparation of suitable carbon materials for sodium-ion batteries (SIBs) is still a challenge. In this paper, N-doped porous carbon material (NDPCs) with rose-like structure has been successfully prapared through pyrolysis of the as-prepared polyimides in-situ. The NDPCs shows rose-like structure derived from 2D nanosheets, an expanded interlayer distance of 0.387 nm, a high specific surface area of 215.7 m 2 g −1 and the electrochemical performances for Na-ion batteries are systematically investigated. A high reversible specific capacity of 240 mAh g −1 at a current density of 100 mA g −1 is attained and a specific capacity of 224 mAh g −1 is remained even after 100 cycles. Remarkably, even at a high current density of 3.2 A g −1 , the reversible specific capacity of 104 mAh g −1 can be observed. This excellent performance of NDPCs electrode may be ascribed to its superior structure, since the micropore/mesopore might efficiently shorten the diffusion distance of Na-ion and the enlarged interlayer spacing of 0.38 nm is significant for Na-ion insertion/extraction. Significantly, the approach to prepare carbon materials from PI may be generalized to other polymers. [ABSTRACT FROM AUTHOR]

High-performance supercapacitors are widely studied, but few works have paid attention to the optimization of conductive bonding networks in the electrode to improve its electrochemical performance. Herein, a rationally designed three-dimensional (3D) conductive bonding network consisting of one-dimensional carboxylated carbon nanotubes (CNT-COOH) and two-dimensional reduced holey graphene oxide (rHGO) is introduced to porous carbon nanofiber/ultra-thin MnO 2 nanosheets (PCNF/U-MnO 2) electrode through vacuum filtration. The CNT-COOH/rHGO network endows the electrode with desired electron transport and ion diffusion properties for its advantages in 3D structures, conductivity and electrolyte wettability, which promote efficient use of PCNF/U-MnO 2 active materials. Thus, PCNF/U-MnO 2 in the electrode with CNT-COOH/rHGO network shows better capacitive performance than that of traditionally fabricated electrode with PTFE and acetylene black. Besides, CNT-COOH/rHGO network is conducive to structural stability of PCNF/U-MnO 2 electrode, and it obtains a capacitance retention of 87% even after 4500 cycles. Then, an asymmetric supercapacitor with PCNF/U-MnO 2 cathode and N, B-doped PCNFs anode has been assembled, which exhibits good flexibility using LiCl/PVA hydrogel as electrolyte and has a high energy density of 45 Wh kg−1 at a power density of 540.8 W kg−1. The strategy of CNT-COOH/rHGO network construction can be an effective and promising way beneficial to high-performance supercapacitor fabrication. [Display omitted] [ABSTRACT FROM AUTHOR]

Coal is an earth-abundant energy resource, however, its direct combustion results in serious environmental pollution. Therefore, it becomes important to design value-added products from coal and to maximize its value chain. Herein, brown coal was used to develop non-precious metal catalysts for the oxygen reduction reaction (ORR) in fuel cells as green energy conversion systems. The brown coal was first pretreated with different acids, followed by N-doping at 800 °C in a stream of NH 3 . A trace amount of Fe was further added to improve the electrocatalytic performance of the prepared catalyst towards ORR. The prepared coal-derived N-doped carbon further modified with 0.5% Fe exhibited onset potential of 0.92 V vs. RHE at a current density of −0.1 mA cm −2 and a predominantly 4-electron transfer pathway of oxygen to water in 0.1 M NaOH, which was evaluated by RDE and RRDE. The prepared electrocatalysts were further characterized by elemental analysis, XRD, Raman and XPS. The results suggest that the coal-derived ORR catalyst have convoluted graphitic and amorphous carbon structures. The N-content increased after acid-pretreatment and subsequent functionalization with nitrogen, while it slightly decreased after Fe incorporation apparently due to coordination of Fe with N. ORR activity enhancement after the incorporation of Fe is expected to mainly arise from a synergetic effect involving the interaction of Fe with N groups distributed in the carbon matrix. [ABSTRACT FROM AUTHOR]

This study investigates the effect of boron/nitrogen (B/N) dual doping on the electrocatalytic activity for oxygen reduction reaction (ORR) of carbon materials that are derived from gaseous carbon dioxide (CO 2 ) at 1 atm. In the presence of NaBH 4 , CO 2 was converted to a B-doped carbon material which was further treated with urea at 850 °C for N-doping. Through RDE and RRDE measurements, the enhanced ORR activity of the B/N dual-doped carbon was confirmed in terms of both early onset potentials and large current densities. This arose from the existence of B-N related bond and pyridinic N in the carbon network. As the amount of N content increased, the carbon material became more crystalline and the B/N dual doping led to an increase in the electron transfer number of the carbon materials, implying that the ORR occurred through a dominant four-electron transfer pathway. By utilizing the abundant greenhouse gas as a carbon source, this study provides a facile means by which to synthesize B/N dual-doped carbon for enhanced electrocatalysis. [ABSTRACT FROM AUTHOR]

Ultra-microporosity and heteroatom-doping have been proved to be desired for carbon electrode materials of advanced supercapacitors. In this paper, dual N, S-doped carbon materials with high-developed ultra-micopores (∼0.70 nm) are prepared by direct carbonization of potassium salts of m-amionphenol-m-mecaptophenol co-resin. The morphology, structure and surface properties of the carbon materials are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption, X-ray photoelectron spectroscopy (XPS), and Energy dispersive spectroscopy (EDS). It was found that the reactant ratio of phenols play an important role on the microscopy morphology, pore texture and heteroatom-doping of carbon materials. The potassium ions mono-dispersed in phenolic resins as a form of O − K + deliver a homogenous “ in-situ self-activation ”, thus created developed ultra-microporosity with high uniformity, connectivity and short pore length. Due to the synergy effect of tailored ultra-microporosity and N, S, O-doping, the SNC-3:1-600 carbon shows a high specific capacitance of 250 F g −1 , good capacitance retention of 61% in the range of 0.2–20 A g −1 , low relaxation time constant of 0.71 s in KOH electrolyte. The present preparation strategy is attractive and inspiring for preparation of tunable N, S-doped carbon materials for advanced supercapacitors. [ABSTRACT FROM AUTHOR]

The electrochemical properties of porous carbons used as supercapacitor electrodes are largely determined by the pore size and its distribution. Here, we report that high–mesopore–volume nanocarbons (HMC) produced by one–step sintering process considerably improve the capacitive behavior by providing the desired highly accessible surfaces. The symmetric supercapacitors based on the HMC materials show high gravimetric capacitances of ∼180 and ∼215 F g −1 and also high volumetric capacitances in organic and ionic liquid electrolytes. High mesoporous volume ratio of HMC sample (∼76%) facilitates fast ionic transport while preserving good electronic conductivity and thus delivers both high energy and power density. This simple, cost–effective and scalable preparation technique and excellent capacitive behavior of HMC samples encourage their practical application. [ABSTRACT FROM AUTHOR]

B-N-, Si-N, and S-N-co-doped carbon quantum dots (CQD) were prepared by hydrothermal synthesis from inexpensive and non-toxic precursors. They were analysed by Raman, FTIR, and XPS spectroscopies and used as oxygen reduction reaction (ORR) electrocatalysts. The electrodes were prepared by drop-casting a slurry containing poly(sulfone trimethylammonium) hydroxide (PSU-TMA) to enhance the hydroxide-ion transport near the catalytically active centers. Furthermore, polyaniline (PANI), reported to be catalytically active for the ORR, was added to some electrodes. A similar trend was observed for the electrode capacitance measured by cyclovoltammetry in the non-Faradaic region and impedance spectroscopy. The ORR kinetics studied by linear sweep voltammetry showed the lowest onset and half-wave potentials and the lowest Tafel slopes for the B-N-co-doped samples, although the B concentration is low (0.5%). Data with and without PANI are quite similar. The S-N- and Si-N co-doped samples are slightly less efficient. The stability test demonstrated a decrease by about 10% of the diffusion-limited current after 500 cycles, indicating a microstructural change impacting the mass transport conditions, but the onset potential is not modified. Altogether, the good electrocatalytic activity of B-N-co-doped CQD with a low boron concentration in presence of PSU-TMA indicated the high potential of these electrodes. The inexpensive synthesis of co-doped CQD from non-toxic precursors is an important advantage of these materials vs other carbon-doped electrocatalysts. [ABSTRACT FROM AUTHOR]

In this study, three-dimensional (3-D) architectures consisting of nanostructured polyaniline (PANI) and carbon nanotubes (CNTs) grown on carbonized cotton cloth (CC) were prepared and used as supercapacitors and electromagnetic interference (EMI) shielding materials. The surface morphology and mass of PANI on CNTs were altered by changing the concentration of aniline (AN) precursor in the polymerization reaction. It is found that when the PANI content on CNTs increased, the electric conductivity of nanocomposites decreased and the charge transfer resistance increased remarkably. The highest PANI-deposited nanocomposite was used to fabricate a proof-of-concept symmetric two-electrode supercapacitor, which exhibited an excellent areal specific capacitance of 3.1 F cm–2 (equivalent to a specific volumetric capacitance of 100.5 F cm–3) at the current density of 2.0 mA cm–2. In addition, the EMI shielding performance of the developed nanocomposites was studied, and the results revealed that 3 layers of nanocomposites with a thickness of less than 1 mm demonstrated an excellent shielding capability with total shielding effectiveness above 40 dB. Based on those findings, it is anticipated that the presented nanocomposite would be a potential candidate for flexible energy storage and EMI shielding applications. [ABSTRACT FROM AUTHOR]

Phenolic resins are usually selected as carbon precursor because it gives high production yield and allow the production of porous carbon with high surface areas and tailored porosity. With the increasing concern on fossil fuel depletion and environmental footprint, there is a strong global interest to explore renewable alternative of phenol–formaldehyde resins. In this work, we prepared alkaline poplar bark extractive-based phenolic resins. Using this bio-base phenolic resin as carbon precursor, we further obtained a hierarchical porous carbon material with mciro/meso/macro porosity. Due to its unique hierarchical pore texture, the prepared carbon shows superior capacitive performance with high specific capacitance, excellent rate capability and good long-term cycle stability in KOH electrolyte. We believe that this bio-based activated carbon is a kind of economical and promising material because of the simple preparation process, low cost, environmentally friendly and high performance. [ABSTRACT FROM AUTHOR]

The peanut shells derived porous hard carbons (PSDHCs) by pyrolysis have been investigated as anodes of lithium/sodium batteries (LIBs/NIBs). Directly from the starting peanut shells, 600°C is found to be the favorable pyrolysis temperature for preparation of the PSDHC sample (PSDHC-600) with the best electrochemical performances for LIB applications. Furthermore, from the activated peanut shells in KOH solution, the produced PSDHC-600A by pyrolysis at 600°C is observed to offer greatly enhanced Li + /Na + ion storages. For LIB applications, PSDHC-600A delivers a retained capacity of 474 mAhg −1 after 400 cycles at 1 Ag −1 , larger than 314 mAhg −1 of PSDHC-600. At a high current rate of 5 Ag −1 , PSDHC-600A sustains over 10000 cycles with no obvious sign of fade in capacity, and a capacity of 310 mAhg −1 is still retained. For NIB applications, a capacity of 193 mAh g −1 is retained after 400 cycles at 0.25 Ag −1 , higher than 130 mAhg −1 of PSDHC-600. Even at 1 Ag −1 , PSDHC-600A can be stably cycled over 3000 cycles, and a capacity of 129 mAhg −1 is still retained. In comparison to PSDHC-600, the enhanced electrochemical properties of PSDHC-600A can be attributed to the finer porous structure with the increased percentage of nanoscale pores of diameter less than 2 nm and the larger specific surface area. [ABSTRACT FROM AUTHOR]

In this work, nitrogen-doped hierarchical porous carbon materials (NHPCs) are prepared by a two-step method combined of a hard template process and KOH-activation treatment. Low cost and large-scale commercial nano-SiO 2 are used as a hard template. The hierarchical porosity, structure and nitrogen-doped surface chemical properties are proved by a varies of means, such as scanning electron microscopy, transition electron microscopy, N 2 sorption, Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. When the prepared NHPCs materials are used as the electrode materials for supercapacitors in KOH electrolyte, they exhibit very high specific capacitance, good power capability and excellent cyclic stability. NHPC-800 carbon shows a high capacitance of 114.0 F g −1 at the current density of 40 A g −1 , responding to a high energy and power densities of 4.0 Wh kg −1 and 10 000 W kg −1 , and a very short drain time of 1.4 s. The excellent capacitive performance may be due to the synergistic effect of the hierarchical porosity, high effective surface area and heteroatom doping, resulting in both electrochemical double layer and Faradaic capacitance contributions. [ABSTRACT FROM AUTHOR]

Due to their abundant resources and adjustable interlayer distance, carbon materials have great potential to be applied in sodium ion batteries (SIBs) anodes. N-doping is a commonly used strategy to increase the sodium storage sites in carbon materials, which largely enhances the extra capacitive capacity for SIBs. However, there is still a room to enlarge the interlayer distance in N-doped carbon materials to enhance the intercalation capacity. Herein, we use a S-doping strategy to expand the interlayer distance, which is conducive for the Na+ intercalation, and simultaneously optimize the doping sites in carbon materials to graft high proportion of edge-N atoms. As a result, the optimized sample (NSCRs) exhibits a high reversibly capacity (479.5 mAh g−1 at 100 mA g−1 over 200 cycles) and achieves an ultra-long cycling stability (181.3 mA h g−1 at 5 A g−1 over 10,000 cycles). Theoretical simulation confirms the superiority of Na+ adsorption in NSCRs. The full-cell performance further confirms the practical application potential of NSCRs in SIBs. This work contributes to further understand the optimization of secondary large doping atom to improve the sodium storage sites in N-doped carbon materials. Graphical abstract for the table of contents (TOC): We have expanded the interlayer distance of graphitic lattice by the S-doping engineering, and it simultaneously introduced much more defects which enabled a high proportion of edge-N doping in the carbon materials, which exhibits excellent sodium storage performance (479.5 mAh g−1 at 0.1 A g−1 after 200 cycles and 181.3 mAh g−1 at 5 A g−1after 10,000 cycles) [Display omitted] [ABSTRACT FROM AUTHOR]

The preparation of biomass derived carbon materials usually suffers from complicated and time-consuming procedures, which severely limits their large-scale application. In this work, a modified molten salt-assisted carbonization strategy is proposed to obtain biomass derived porous carbon materials in a convenient way. In particular, the rice-paper plant (RRP) is used as the carbonaceous precursor, and the role of molten salt in the whole reaction process is comprehensively investigated. Under the action of molten salt, oxide impurities can be easily removed by ultrasonication, and both the pickling and activation process are eliminated. The as-obtained carbonized product (MS-RRP) with robust pore structure is obtained with excellent supercapacitor and lithium-ion battery performance. The universality of this strategy towards porous carbon materials production is then verified by using different biomass as raw materials, which is vital for controlling the cost of potential large-scale manufacturing. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Presented paper describes and critically comments major recent strategies for improving electrochemical capacitor performance. Particularly, carbon based electrodes and aqueous electrolytes have been considered. A novel concept of redox active electrolytes as a source of pseudocapacitance effect as well as profits and cons of such system have been discussed. The electrochemical performance of capacitor operating in such electrolyte solution is reported. Furthermore, some advantageous features of bio-inspired system based on bromine-cerium solution acting as oscillator are also presented. [Copyright &y& Elsevier]

Abstract: Effect of surfactants present in alkaline solutions on the capacitance of carbon electrodes has been studied. Different types of surfactants, i.e., sodium and lithium dodecyl sulphate as anionic surfactants, tetrapropylammonium bromide and iodide as cationic surfactants and polymer of polyethylene glycol and p-t-octylophenol (commercially called Triton® X-100) as non-ionic one have been selected for this target. Concentration of these electrolyte additives was 0.005molL−1. Decreasing the surface tension in the electrode/electrolyte interface allows better penetration of electrolyte into the pores. However, surfactants played a different role depending on the electrode polarity. Detailed analysis of capacitance versus current load, frequency dependence as well as self-discharge, cyclability and behaviour in wider voltage range proved especially a profitable effect of Triton® X-100 on capacitor operating in alkaline solution. Influence of surfactant concentration on capacitance properties was also investigated. [Copyright &y& Elsevier]

Abstract: A gold nanoparticles (Au NPs)-graphene nanocomposite (Au–graphene nanocomposite) was prepared by electrochemically depositing Au NPs on the surface of graphene sheets, and characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray powder diffraction (XRD), and electrochemical methods. The morphology and size of the Au NPs could be easily controlled by adjusting the electrodeposition time and the concentration of precursor (AuCl4 −). The electrocatalytic activities of the nanocomposites toward oxygen reduction and glucose oxidation were investigated by cyclic voltammetry. The results indicated that the nanocomposites had a higher catalytic activity than the Au NPs or graphene alone, indicating the synergistic effect of graphene and Au NPs. Therefore, this study has provided a general route for fabrication of graphene-based noble metal nanomaterials composite, which could be potential utility to fuel cells and bioelectroanalytical chemistry. [Copyright &y& Elsevier]

Abstract: The direct electrochemistry of glucose oxidase (GOx) integrated with graphene was investigated. The voltammetric results indicated that GOx assembled on graphene retained its native structure and bioactivity, exhibited a surface-confined process, and underwent effective direct electron transfer (DET) reaction with an apparent rate constant (k s) of 2.68s−1. This work also developed a novel approach for glucose detection based on the electrocatalytic reduction of oxygen at the GOx–graphene/GC electrode. The assembled GOx could electrocatalyze the reduction of dissolved oxygen. Upon the addition of glucose, the reduction current decreased, which could be used for glucose detection with a high sensitivity (ca. 110±3μAmM−1 cm−2), a wide linear range (0.1–10mM), and a low detection limit (10±2μM). The developed approach can efficiently exclude the interference of commonly coexisting electroactive species due to the use of a low detection potential (−470mV, versus SCE). Therefore, this study has not only successfully achieved DET reaction of GOx assembled on graphene, but also established a novel approach for glucose detection and provided a general route for fabricating graphene-based biosensing platform via assembling enzymes/proteins on graphene surface. [Copyright &y& Elsevier]

Abstract: The electrochemical corrosion behavior of a set of porous carbonaceous materials of interest as catalyst supports for polymer electrolyte membrane fuel cells was examined in 2M H2SO4 at 80°C at constant electrode potential of 1.2V vs. RHE. Correlations have been observed between the specific rates of corrosion of carbon materials and carbon-supported Pt catalysts on the one hand and their substructural characteristics derived from X-ray diffraction analysis on the other hand. Carbon supports of the Sibunit family and catalytic filamentous carbons possess lower specific (i.e., surface area normalized) corrosion currents compared to conventional furnace black Vulcan XC-72 and better stabilize Pt nanoparticles. [Copyright &y& Elsevier]

• Telluride was successfully doped into the highly graphitized porous carbon as the non-noble metal catalyst (ZnCo-Te@NC). • The as-prepared ZnCo-Te@NC catalyst had excellent bifunctions for ORR and OER, exceeding the Pt/Ir based precious metal catalysts. • This is the first report that telluride has been doped into a highly graphitized carbon layer for use in zinc air batteries. The development of high-efficiency, low-cost, and stable bifunctional catalysts towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of great significance to the large-scale application of zinc–air batteries. Here we synthesized a telluride (Te)-doped porous carbon catalyst (ZnCo-Te@NC) through pyrolyzing ZnCo-MOF-coated Te nanotubes. The as-prepared ZnCo-Te@NC exhibited excellent bifunctional electrocatalytic performance with an impressive half-wave potential (E 1/2) of 0.873 V for ORR and a low overpotential of 400 mV at 10 mA cm−2 for OER, outperforming most non-noble metal-based catalysts previously reported. When using ZnCo-Te@NC as the air cathode catalyst in a self-assembled battery, it demonstrated smaller charge-discharge voltage gap (0.932 V at 50 mA cm−2) and higher peak power density (259.7 mW cm−2) with robust long-term (100 h) cycle stability, surpassing the benchmark precious metal catalyst-based batteries. This is the first report that telluride has been doped into a highly graphitized porous carbon for use in zinc-air batteries. This work provides an effective strategy to develop high graphitized carbon materials by telluride modification to enhance the performance of bifunctional electrocatalysts for Zn–air batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Enhancement of electrochemical capacitance and morphological variations of various acetylene blacks caused by electrochemical polarization are presented. Acetylene blacks of different mean particle diameters were modified by air-oxidation and heat treatment to diversify the morphologies of the acetylene blacks before electrochemical polarization. The various acetylene blacks were electrochemically oxidized at 1.6V (vs. Ag/AgCl) for 10s and the polarization step was repeated until the capacitance values did not change any longer. These polarization steps enhanced the capacitances of the acetylene blacks and the specific enhancement factors range from 2 to 5.5. Such an enhancement is strongly related to morphological modification as revealed by transmission electron microscopic observations. The electrochemical polarization resulted in formation of tiny graphene sheets on the wide graphitic carbon surfaces, which were most responsible for the observed capacitive enhancement. Although the pseudo-capacitance increased after polarization by forming oxygenated species on the surfaces, its contribution to the total capacitance was less than 10%. The mechanism of the formation of the tiny graphene sheets during the electrochemical oxidation is described schematically. [Copyright &y& Elsevier]

• Low-current galvanostatic measurement of carbons with different porosity was carried out. • Chronopotentiograms show strong dependence of their linearity on the porosity of carbon materials. • Nonlinearity of the charging curves may appear due to the nonequipotentiality of the surface of porous materials. In the analysis of electrochemical behavior of electrical double layer capacitors (EDLC), it is generally accepted that the linear form of chronopotentiograms testifies to the ideal polarization of the electrode and any deviations from the linearity are interpreted most often as the appearance of Faraday processes on the electrode surface. However, studies on electrochemical behavior of supercapacitors based on carbon materials should take into account the surface nonequipotentiality caused by the porosity of electrode materials, which complicates the formation of electrical double layer (EDL). The influence of this factor is clearly demonstrated by the results obtained in this work with the use of micro- and mesoporous carbon materials of different origin. To accurately estimate the dependence of linearity of chronopotentiograms on porosity of the electrode material, low current densities were used (from 0.008 to 0.08 mA/cm2). A comparison of charge curves at different charge currents showed that the time dependence of voltage changes considerably with an increase in the current load. A formal comparison of chronopotentiograms linearity obtained at different current loads was made using dimensionless coordinates on the time axis, which were expressed as a percentage of the overall polarization time. Only the charging branch of chronopotentiogram was analyzed here because the anodic branch had similar formal characteristics. Low-current galvanostatic studies of EDLC prototypes based on carbon materials with different porosity revealed a strong dependence of the shape of the charge-discharge curves on the pore sizes of the resulting electrodes [Display omitted] [ABSTRACT FROM AUTHOR]

To achieve the two-electron governed oxygen reduction reaction (ORR) is the major challenge for carbonaceous catalyst in the electro-Fenton (EF) degradation on the exhaustive stubborn pollutants from industrial wastewater. Herein, a bifunctional salts strategy utilizing EDTA-2K and NaH 2 PO 2 .H 2 O as heteroatom dopants and porogens is proposed to regulate the doping amounts of N, P heteroatoms as well as the content of active species (pyrrolic-N and P-C bonding motifs) to enhance 2e--ORR selectivity for EF degradation. It is found that the generated gaseous substances could serve as soft template to create micro-/meso-pores for the accommodation of highly oxidizing .OH radicals. In addition, thanks to the high N, P doping amounts (both are 2.9 at. %, respectively), large specific surface area (1388 m2 g-1) and appropriate pore sizes (1.5/3.8 nm), the optimized carbonaceous catalyst enables high EF degradation efficiencies up to 98.4 % (60 min) and 97.1 % (150 min), respectively for methyl yellow and mixed dyes with good stability and reusability. The current work paved a new concept to engineer the carbonaceous catalysts for the promoted catalytic activity and selectivity in the electro-degradation of organic pollution. [ABSTRACT FROM AUTHOR]

• A facile MOF template-guided method was developed to prepare SnS/nitrogen-doped carbon sheets. • SnS nanoparticles were well dispersed and anchored on the MOF-derived carbon sheets. • The composite anode demonstrated an enhanced electrochemcial sodium-storage performance. Tin monosulfide (SnS) has emerged as a promissing host material toward sodium-storage for its low cost and high capacity. Nevertheless, unavoidable capacity fading as well as poor rate capability have severely hindered the extended practical application of SnS. Carbon coating is an effective strategy to address these issues. In this paper, a SnS coupled with nitrogen-doped carbon hybrid (SnS/NCS) has been fabricated through an easy template method with a 2D tin-based metal organic framework (Sn-MOF) as precursor. By an annealing and sulfuration treatment, ultrasmall SnS nanoparticles are well in-situ formed and embedded onto MOF-derived nitrogen-doped carbon sheets. Conductive carbon components can provide electron expressway and robust mechanical support. Furthermore, the confining effect of carbon matrix on SnS nanoparticles effectively alleviates the volume expansion. Having profited from the desirable nanostructures, SnS/NCS anode achieves an extremely improved electrochemical property for sodium-storage. At the end of 150 cycles under a current density of 100 mA g−1, SnS/NCS remains a high capacity of ~522 mAh g−1. Besides, even at a large current density of 1000 mA g−1, SnS/NCS still keeps a capacity of ~321 mAh g−1 after finishing 200 cycles of test and achieves an enhanced rate capability. [Display omitted] [ABSTRACT FROM AUTHOR]

• A zinc acetate-assisted pyrolysis strategy has been developed for the synthesis of porous carbons from glycerol. • The content of zinc acetate has a profound influence on the textural parameters of the resulting samples. • Carbon formation mechanism and the morphology evolution process has been proposed. • The obtained nanocarbons exhibit large surface area and ultra-high mesopore content. • Aqueous zinc ion hybrid supercapacitors with superior rate capability have been realized. Direct transformation of small molecular organic solvents (SMOSs) into functional carbon materials have received paramount interests in recent years, although it remains a huge challenge. Herein, we demonstrate an efficient zinc acetate-assisted pyrolysis strategy to direct transformation of glycerol into mesopore‐enriched hierarchically carbon nanosheets (MEHCs). We found that the initial formed glycerin zinc would be one of the major ways in immobilization of glycerol from volatilization as well as determining the morphology of the resulting carbons. By optimizing the amount of zinc acetate, MEHCs with large specific surface area (1666.8 m2 g−1), ultra-high mesopore content (S meso = 1488.7 m2 g−1) and total pore volume (2.42 cm3 g−1) were obtained. Benefiting from the unique structure features, the as-assembled aqueous zinc ion hybrid supercapacitors with the as-prepared MEHCs as the cathodes can deliver a specific capacity of 132.9 mAh g−1, and rate capability up to 49.1% at 50 Ag−1, which is one of the largest values in comparison with the previously reported values. Such promising results indicate that the newly developed strategy would offer a valuable avenue for the production of functional nanocarbon materials from SMOSs for electrochemical energy storage applications. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper reports on the charging mechanism of an activated carbon electrode in a symmetric electrochemical capacitor operating in an ionic liquid electrolyte (EMIm+TFSI−). With the application of step potential electrochemical spectroscopy (SPECS) and electrochemical dilatometry, it is determined that the electrical double-layer formation mechanism strongly depends on the porous structure of the electrode material. Furthermore, SPECS calculations allow us to separate and quantify the charge component responsible for the ionic movement. [Display omitted] [ABSTRACT FROM AUTHOR]

Solid-phase templates are commonly used for building hollow-structured carbon materials (CMs) but often demand post treatments to remove templates. Herein, we develop an efficient and general method to construct hollow carbonaceous structure via the templating of sacrificial carbon nitride (termed as f-NC) without post treatment. The f-NC template can be decomposed under high-temperature annealing, additionally, it can serve as N source to enrich the N content. Applying f-NC template, we manage the synthesis of hollow-structured highly dispersed binary FeCo-nitrogen-carbon material (termed as f-NC@FeCo-NC). Its hollow feature is confirmed by direct observation using HRTEM. Meanwhile, Fe/Co in oxidation states have been verified uniformly distributing in heavily N-doped CMs (N content ∼ 13.2 at.%). The resulted f-NC@FeCo-NC, as examined by electrochemical measurements, exhibits highly efficient performance toward oxygen reduction reaction (ORR) in alkaline medium. It respectively shows much enhanced onset and half-wave potentials of 1.01 and 0.89 V relative to the FeCo-NC that is obtained without f-NC, in contrast, 20 wt% Pt/C shows 0.95 V onset potential and 0.83 V half-wave potential. The f-NC@FeCo-NC catalyst also shows excellent Al-air battery performance when applied as cathode, which possesses a high open circuit voltage of 1.91 V and a high peak power density of 241 mW cm−2. We believe this sacrificial f-NC can be applied as general template for the fabrication of other hollow-structured carbon-based materials for broad electrochemical applications. [ABSTRACT FROM AUTHOR]

Soft- and salt-templating methods have been combined to obtain highly microporous carbon materials with mesopores in the narrow pore size range. Phenolic resin was used as a carbon source, and rubidium and caesium chloride were used as salt-templates, giving a well-developed microporosity with a high specific surface area, whereas a sacrificial triblock polymer Pluronic F-127 (soft-template) induced the mesopores of essential importance for fast access of the electrode surface area for the electrolytic solution. The combination of a high specific surface area (up to 2556 m2 g−1) with a suitable pore size (0.77–0.88 nm) resulted in an excellent performance of the electrochemical capacitor. High specific energies of 16.7 Wh∙kg−1 at 300 W kg−1 of specific power have been achieved for a CsCl-T-based high-voltage (1.5 V) device with a 0.5 mol⋅L−1 Li 2 SO 4 electrolytic solution. The improved rate handling was allowed to maintain 10 Wh⋅kg−1 of specific energy at 4 kW kg−1 of specific power. In contrast to the other carbons with well-developed porosities, the material density obtained allowed our device to reach competitive, remarkably higher volumetric characteristics. [ABSTRACT FROM AUTHOR]

Nitrogen atoms doping was widely recognized as the promising technique to improve the electrochemical performances of various carbonaceous materials application for energy storage devices. Herein, we reported a facial fabrication of highly N-doped graphene-like carbon (NGC) through the carbonization of a mixture containing polypyrrole and g-C 3 N 4 nanosheets, which was employed as sacrificial template and extra nitrogen source simultaneously. The resultant NGC material integrate a range of excellent features including high nitrogen contents (17.54 at%), large specific surface areas (635.73 m2 g−1) and abundant mesopores with high pore volume (1.9483 cm3 g−1). As anode material in Li-ions batteries, the NGC material exhibits an promising initial discharge capacity of 2749 mAh g−1 at a current density of 50 mA g−1 and encouraging cycling stability (1143 mAh g−1 after 200 cycles) as well as excellent rate performance (440 mAh g−1 at 2 A g−1). This feasible fabrication presents a new guidance to exploit high performance N-doped carbon materials for the applications in energy storage devices. A facial fabrication of highly N-doped graphene-like carbon (NGC) was reported in this paper by employing g-C 3 N 4 nanosheets as the sacrificial template and extra nitrogen source simultaneously. Outstanding electrochemical Li-ions storage performances were demonstrated owing to the integrated features including high nitrogen contents (17.54 at%) and abundant mesoporous with high pore volume (1.9483 cm3 g−1). Image 1004 [ABSTRACT FROM AUTHOR]

Carbon materials are widely applied as conductive additives in studies of the oxygen evolution reaction (OER) in alkaline media catalyzed by transition metal oxides. In this work we investigate the anodic behavior of three representative carbon materials: furnace black (Vulcan XC-72R), acetylene black, and pyrolytic carbon of the Sibunit family (Sibunit-152), in 1 M NaOH at high potentials (ranging from the OER onset and up to ca. 2 V vs. RHE) in the time span from several minutes to several hours. We apply the rotating ring-disk electrode (RRDE) to separate the OER current from the carbon corrosion current. We then use transmission electron microscopy (TEM) to visualize changes in the carbon morphology resulting from corrosion. Finally, we study the OER performance of composite electrodes comprising carbon materials mixed with a La 0.5 Sr 0.5 Mn 0.5 Co 0.5 O 3−δ perovskite OER catalyst, and discuss possible influence of the oxide on the carbon corrosion. [ABSTRACT FROM AUTHOR]

In the field of renewable energy, the core of advanced materials lies in the efficiency for the electrocatalytic and photoelectrochemical overall water splitting. However, in hydrogen evolution reaction (HER), there is a lack of electrocatalysts based transition metals of high-performance and natural-abundance, and thus there is a formidable challenge for large-scale application. Therefore, molybdenum carbide (Mo 2 C) based catalysts and their composites are regarded as a most promising and replacement noble metal electrocatalyst for the HER in different media about all pH. In this work, the preparation of ultra-fine Mo 2 C nanoparticles, which uniformly implant into hollow N-doped carbon polyhedrons (Mo 2 C@HNCPs) by adopting MOF-assisted self-sacrifice template approach, is proposed. Mo 2 C@HNCPs showcases suitable catalytic activity and feasible stability toward HER in both media such as acidic and alkaline solutions. The as-prepared Mo 2 C@HNCPs exhibits effective and fast response from the HER region with nearly 0.0 V onset overpotentials, only requiring 89 mV (0.5 M H 2 SO 4 media) and 87 mV (1.0 M KOH media) overpotential to reach 10 mA cm−2 and cycling stability (<5% performance loss after 10 h). Such distinctive activity of HER is mainly imputed to the poly-dispersion of the ultra-fine Mo 2 C nanoparticles and its synergistic contribution of rich nitrogen doping, unique hollow morphology, and abundant active sites at the heterostructures. The synthesis of ultra-fine Mo 2 C nanoparticles is uniformly embedded into hollow N-doped carbon polyhedrons (Mo 2 C@HNCPs) by a MOF-assisted self-sacrifice template approach. As the HER electrocatalyst, Mo 2 C@HNCPs shows better catalytic activity and feasible stability toward HER in both acidic and alkaline media. Such HER activity is attributed to the ultra-fine Mo 2 C nanoparticles and synergistic contribution of nitrogen doping, unique hollow structure, and abundant active sites at the heterostructures. Image 1 • A new approach of the MOF-assisted self-sacrifice template is successfully obtained and outlined. • Ultra-fine Mo 2 C nanoparticles are uniformly embedded into hollow N-doped carbon polyhedrons by a simple thermal treatment. • The as-obtained catalyst (Mo 2 C@HNCPs) is of better HER performance and long-term stability in the real application. [ABSTRACT FROM AUTHOR]