Mesoporous Carbon Framework Research Articles

Mild Ammonia Synthesis over Ba-Promoted Ru/MPC Catalysts: Effects of the Ba/Ru Ratio and the Mesoporous Structure

A series of novel mesoporous carbon-supported, Ba-promoted, Ru catalysts with Ba/Ru ratios of 0.1–1.6 and a Ru loading of 10 wt% (denoted as 0.1–1.6Ba-10Ru/MPC) were prepared via stepwise impregnation of Ru and Ba precursors on the mesoporous carbon materials. The catalysts were applied to mild ammonia synthesis and compared to reference materials, including an analog of the prepared catalyst with a Ba/Ru ratio of 1.6 and a Ru loading of 10 wt% (denoted as 1.6Ba-10Ru/AC). Characterization by X-ray diffraction (XRD), nitrogen physisorption, and electronic microscopy revealed that the 0.1–1.6Ba-10Ru/MPC catalysts contained Ru particles (approximately 2 nm) that were well-dispersed on the mesoporous structure and nanostructured Ba(NO3)2 species. These species decomposed into amorphous BaOx species, acting as a promoter on the metallic Ru particles forming catalytically active sites for ammonia synthesis. All the 0.1–1.6Ba-10Ru/MPC catalysts showed a synergistic effect of the active Ba and Ru species, which were stabilized in the mesoporous carbon framework with fast molecular diffusion and could effectively catalyze mild ammonia synthesis (280–450 °C and 0.99 MPa) even under intermittently variable conditions, particularly for those with Ba/Ru ratios of >0.5. In contrast, the 1.6Ba-10Ru/AC analog showed poor activity and stability for ammonia synthesis due to the sintering of Ba and Ru particles on the outer surface of the microporous carbon framework, resulting in low molecular diffusion and weak synergistic effect of the catalytically active sites.

Co3O4 nanoparticles supported mesoporous carbon framework interface for glucose biosensing

The present work reports the preparation of advanced functional nanostructures based on cobalt oxide supported mesoporous carbon framework (Co3O4@MCF) for electrochemical biosensing. Co3O4@MCF was synthesized by simple hythrothermal & pyrolysis method and further characterized by various microscopic and spectroscopic techniques. The transmission electron microscopic (TEM) images show the lattice fringes of crystalline Co3O4 with interlayer spacing of 0.24 nm. The characteristic 311 plane in X-ray diffraction (XRD) studies further confirmed the presence of crystalline Co3O4 on carbon frameworks. Reflection of prominent A1g peak along with D and G band in raman spectra confirmed the successful fabrication of Co3O4@MCF nanocomposite. Prepared Co3O4@MCF manifested great porosity, good biocompatibility and large surface area which allowed effective immobilization of glucose oxidase (GOx) onto its surface using chitosan (Chi) as a binder. Thus, a nanocomposite (Co3O4@MCF-Chi-GOx) modified glassy carbon electrode (GCE) was fabricated for highly selective detection of glucose using amperometry and cyclic voltammetry. The Co3O4@MCF-Chi-GOx/GCE electrode exhibited excellent biosensing performance for glucose monitoring with detection limit of (LOD) of 107.70 μM and reproducibility of 4.7% RSD. Moreover, the biosensor holds great promise for its effective implications in point-of-care diagnostics of small biomolecules.

Energy Efficient and Intermittently Variable Ammonia Synthesis over Mesoporous Carbon-Supported Cs-Ru Nanocatalysts

The Cs-promoted Ru nanocatalysts supported on mesoporous carbon materials (denoted as Cs-Ru/MPC) and microporous activated carbon materials (denoted as Cs-Ru/AC) were prepared for the sustainable synthesis of ammonia under mild reaction conditions (<500 °C, 1 MPa). Both Ru and Cs species were homogeneously impregnated into the mesostructures of three commercial available mesoporous carbon materials annealed at 1500, 1800 and 2100 °C (termed MPC-15, MPC-18 and MPC-21, respectively), resulting in a series of Cs-Ru/MPC catalysts with Ru loadings of 2.5–10 wt % and a fixed Cs loading of 33 wt %, corresponding to Cs/Ru molar ratios of 2.5–10. However, the Ru and Cs species are larger than the pore mouths of microporous activated carbon (shortly termed AC) and, as a consequence, were mostly aggregated on the outer surface of the Cs-Ru/AC catalysts. The Cs-Ru/MPC catalysts are superior to the Cs-Ru/AC catalyst in catalysing mild ammonia synthesis, especially for the 2.5Cs-10Ru/MPC-18 catalyst with a Ru loading of 10 wt % and a Cs/Ru ratio of 2.5, which exhibited the highest activity across a wide SV range. It also showed an excellent response and stability during cycling tests over a severe temperature jump in a short time, presumably due to the open mesoporous carbon framework and suitable surface concentrations of CsOH and metallic Ru species at the catalytically active sites. This 2.5Cs-10Ru/MPC-18 catalyst with high activity, fast responsibility and good stability has potential application in intermittently variable ammonia synthesis using CO2-free hydrogen derived from electrolysis of water using renewable energy with fast variability.

Enhanced N-doping in mesoporous carbon for efficient electrocatalytic CO2 conversion

The capability of electrocatalytic reduction of carbon dioxide (CO2) using nitrogen (N)-doped carbon strongly depends on the N-doping level and their types. In this work, we developed a strategy to generate mesoporous N-doped carbon frameworks with tunable configurations and contents of N dopants, by using a secondary doping process via the treatment of N,N-dimethylformamide (DMF) solvent. The obtained mesoporous N-doped carbon (denoted as MNC-D) served as an efficient electrocatalyst for electroreduction of CO2 to CO. A high Faradaic efficiency of ∼ 92% and a partial current density for CO of −6.8 mA·cm−2 were achieved at a potential of −0.58 V vs. RHE. Electrochemical analyses further revealed that the active sites within the N-doped carbon catalysts were the pyridinic N and defects generated by the DMF treatment, which enhanced the activation and adsorption CO2 molecules. Our study suggests a new approach to develop efficient carbon-based catalysts for potential scalable CO2RR to fuels and chemicals.

Intertwined Nitrogen‐Doped Carbon Nanotube Microsphere as Polysulfide Grappler for High‐Performance Lithium‐Sulfur Batteries

AbstractA kind of yarn‐like nitrogen‐doped carbon nanotubes microsphere (NSCNT) is synthesized in one‐step synthesis, and sulfur is added by melting immersion to form carbon nanotube microspheres/sulfur composites (NSCNT/S). The morphology, structure and electrochemical property of the obtained NSCNT/S are explored by field‐emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD) and electrochemical tests. The results show that NSCNT possesses a high N content and unique mesoporous carbon framework with large specific surface area of 1029 m2 g−1, which can not only favor rapid electron and Li‐ion transfer but also effectively mitigate dissolved polysulfides via strong chemical and physical adsorption. Due to the synergetic interaction of NSCNT, the NSCNT/S delivers a high initial discharge capacity of 1241.3 mAh g−1 at 0.1 C and large rate capacity of 1175.5 mAh g−1 at 1 C with ultralow capacity decay of 0.1 % per cycle and high areal mass loading of 3.1 mg cm−2. This eco‐friendly NSCNT/S can offer an appealing improvement for the applications of high‐performance lithium‐sulfur batteries.

Bimetal/Metal Oxide Encapsulated in Graphitic Nitrogen Doped Mesoporous Carbon Networks for Enhanced Oxygen Electrocatalysis

AbstractIn this study, Fe doped, Co and CoO encapsulated N doped carbon frameworks were prepared from simple hybrid zeolite imidazole frameworks (ZIF) with extra N enrichment. The facile strategy included preparation of ZIF‐8 core and ZIF‐67 shell and later replacing the metal centers of ZIF with Fe ions and increasing the N content with N rich melamine. The metal and metal oxide components got captured and encapsulated in the N doped mesoporous carbon frameworks through a pyrolysis process at different temperatures. Fe, Co and CoO were trapped in the N doped mesoporous carbon networks through annealing and denoted as FCNCx. The activity and electrochemical stability of such prepared materials towards ORR and OER were tested in basic media. After analyzing rotating disk electrode studies, FCNC900 was seen to perform superior bifunctional electrocatalytic performance for both ORR and OER which was higher than Pt/C catalyst. Promising ORR performance of FCNC900 can be simply be judged from E1/2=0.868 V (vs. RHE) and Eonset=1.01 V (vs. RHE) while OER overpotential for same catalyst was 360 mV much smaller than others. Longer stability and high methanol tolerance of this catalyst was also investigated.

Ultrafine NiMoOx nanoparticles confined in mesoporous carbon for the reduction of nitroarenes: effect of the composition and accessibility of the active sites

The design of ultrafine NiMoOx nanoparticles (NPs) confined in hierarchically porous carbon remains a great challenge due to its high calcination temperature. In addition, the composition of active sites of NiMoOx NPs for the hydrogenation reaction is still ambiguous. Herein, we report a general approach for the synthesis of ultrafine NiMoOx NPs confined in mesoporous carbon with different morphologies and compositions using the replication method with SBA-15 as a hard template. The pore structure of mesoporous carbon and the Ni/Mo composition valence-state were discovered to be the main factors in the reduction of nitroarenes. The NiMoOx/mesoporous carbon-platelet (NiMoOx/MC-PL) with short mesochannels (∼350 nm) and high surface area (∼995 m2 g−1) possessed excellent catalytic activity towards the reduction of 4-nitrophenol, whereas NiMoOx/mesoporous carbon-hexagonal-prism (NiMoOx/MC-HP), NiMoOx/mesoporous carbon-long-rod (NiMoOx/MC-LR), and NiMoOx/mesoporous carbon-spherical (NiMoOx/MC-SP) with long mesochannels and relatively less surface area exhibited poor catalytic performance. The bifunctional mechanism or electronic synergistic effects of Ni and Mo species enhanced their catalytic performance. A good balance between MoOx and metallic Ni (NiMoOx/MC-PL-450) was found to be suitable for the reduction of 4-NP.

Capacitive deionization of saline water using graphene nanosphere decorated N-doped layered mesoporous carbon frameworks

Capacitive deionization (CDI) is an alternative water purification technology.

Coordination‐Self‐Assembly Approach toward Aggregation‐Free Metal Nanoparticles in Ordered Mesoporous Carbons

AbstractMultifunctional ordered mesoporous carbon materials that feature high surface area, uniform pores, good conductivity of the carbon skeletons, and specific host‐gust interactions, which are of interest for a wide variety of applications, for instance, catalysis, photonics, bioscience, and energy storage, are presented. Here, we establish a facile and generalizable “coordination‐assisted self‐assembly” for encapsulation of aggregation‐free and highly dispersed metal nanoparticles inside the mesoporous carbon frameworks. The choice of pyrogallol as phenolic resin precursor is essential for the in situ encapsulation, because the strong coordination between the three hydroxide groups of pyrogallol and metal ions favors the immobilization of transition metal into the mesopores, and then suppress the sintering of metal nanoparticles at high carbonization temperatures. The metal supported mesoporous composites possess the very high loading content of 1.25 %–7.27 %, tiny particle sizes of 4.3–15.6 nm and high surface area of 475–589 m2/g. The unique structure in deed endows high sulfur loading content in the conductive mesoporous carbon channels, and meanwhile metal nanoparticles as catalyst effectively promotes the electrochemical conversion of polysulfides, resulting in a high reversible capacity, excellent rate capability and good cycling stability for Li−S batteries.

A molecular-based approach for the direct synthesis of highly-ordered, homogeneously-doped mesoporous carbon frameworks

Heteroatom doping of carbonaceous materials can effectively modulate their physiochemical properties, providing great potentials to design innovative architectures with enhanced performance for energy-related applications. Herein, we report a versatile molecular-based strategy for the in-situ synthesis of highly-ordered, heteroatom-doped mesoporous carbon frameworks (MCFs). Our approach is based on the transformation of self-assembled superlattices consisting of Fe3O4 nanocrystals (NCs) with desired surface-coating molecular species, which are realized by exploiting versatile surface chemistry of colloidal NCs. By this strategy, various heteroatoms, such as N, B, and S, can be directly incorporated into the simultaneously formed MCFs with a homogeneous distribution. Taking advantage of their highly ordered and interconnected mesoporosity, tunable doping level, and high surface area, such heteroatom-doped MCFs show great promise for energy-related applications. We show that the N-doped MCFs (N-MCFs) exhibit significantly enhanced catalytic activity relative to their undoped counterparts when evaluated as electrocatalyst for oxygen reduction reaction. Likewise, the N-MCFs can also be used as electrode material for constructing supercapacitors with outstanding cycling stability and rate performance. This work offers a surface chemistry approach for the direct synthesis of highly-ordered MCFs containing homogeneously distributed heteroatoms, which are suitable for applications in various energy conversion and storage devices.

Using Multifunctional Polymeric Soft Template for Synthesizing Nitrogen and Phosphorus Co–Doped Mesoporous Carbon Frameworks Electrocatalysts for Oxygen Reduction Reaction

AbstractTo replace high‐cost and non‐resistant platinum‐based electrocatalysts for oxygen reduction reaction (ORR), the development of low‐cost, durable and high‐efficiency nonprecious metal catalysts is urgently needed. Thereinto, metal‐free heteroatom‐doped carbon materials as one of the promising candidates are quite satisfying for its designability of material properties, remarkable electrocatalytic activity and unexceptionable durability. In this work, a novel and rational method by using multifunctional polymeric soft template: poly [cyclotriphosphazene‐co‐(4, 4’‐(hexafluoroisopropylidene) diphenol)] (PZAF) particles for synthesis PZAF@PANI composite which is further treated under high temperature for generating N, P co‐doped mesoporous carbons (NPMPCs) is utilized. The resultant NPMPCs exhibit a mesoporous structure with ultra large specific surface area (1465.091 m2 g−1) and total pore volume (1.068 cm3 g−1), which can optimize the ORR active sites derived from the N, P co‐doping. Based on these structural features, NPMPCs possess outstanding ORR activity, admirable durability and brilliant methanol tolerance, comparable or even better than that of commercial 20% Pt/C. The correlationship between the particular porous structure derived from the decomposition of PZAF particles and the nitrogen and phosphorus species in the carbon frameworks of the electrocatalysts with considerable catalytic activity are thoroughly investigated.

Ultrafine SnO2 nanoparticles encapsulated in ordered mesoporous carbon framework for Li-ion battery anodes

Ultrafine SnO2 particles are encapsulated in the hollow nanochannels of ordered mesoporous carbon (OMC) framework by simple infiltration of tin precursor and heat treatment. The SnO2@OMC anode delivers excellent cyclic stability with a reversible specific capacity of ∼1000 mAh g−1 after 100 cycles at 100 mA g−1 for Li-ion batteries (LIBs). It also presents an excellent rate performance with a specific capacity of 680 mA g−1 at a high current density of 500 mA g−1. Several functional features and ameliorating geometries play positive roles in Li-storage performance and stability of the electrode. They include (i) the intimate electrical contacts between the SnO2 nanoparticles and the walls of OMC channels to facilitate fast ion/electron transfer, (ii) the large surface area originating from the unique architecture of the composite, and (iii) the encapsulation of SnO2 particles within the channels to suppress their volume expansion during charge/discharge cycles. The reversibility of the conversion reaction is also supported by the high Li-ion diffusion coefficient with enhanced electrochemical reaction kinetics. Based on the above findings, this work may offer new insights into the rational nanostructural design of electrode materials for high performance rechargeable batteries.

Ultrathin Sheets of MoS2/g-C3N4 composite As a Hosting Material of Sulphur for Lithium-Sulphur Batteries with Long Cycle Life and High Rate Capability

High energy density rechargeable batteries are the future of energy storage systems. Lithium ion batteries have brought revolutionary changes in the portable electronic devices for more than thirty years. However, the presently available lithium-ion batteries (LIBs) that follow intercalation-deintercalation mechanism cannot fulfil the energy demand of emerging electric vehicles (EVs), hybrid EVs, and next generation portable electronic devices. Therefore, alternative chemistry of lithium-ion batteries has drawn tremendous attention to overcome this bottleneck of high energy demand. Lithium-sulphur batteries holds enormous potential to meet the future energy demands because of its high theoretical specific capacity (1675mAh/g) and cost effectiveness [1]. The specific energy density of lithium-sulphur battery has a theoretical value of 2567Wh/kg, which is significantly higher than the commercially available lithium-ion batteries (387Wh/kg for LiCoO2 with graphite anode) [1]. In spite of the tremendous potential, lithium-sulphur battery systems have some challenging issues hindering its practical usage. The major challenge is the “shuttle effect” of higher order lithium polysulphides (Li2Sn, 4<n<8) between cathode and anode. This is derived from the dissolution of polysulphides in the organic electrolyte. The shuttle effect results in severe capacity loss, poor rate performance and low coulombic efficiency. Another challenge is the high electrical resistivity of elemental sulphur (1015 Ω-m) that prevents the direct utilization of sulphur as an electrode material. In the present study, MoS2/g-C3N4 nanosheets are utilized to chemically confine the lithium polysulphides. Both MoS2 and graphitic carbon nitride (g-C3N4) will provide anchoring sites for lithium polysulphides leading to superior cycling and rate performance. X-Ray photon spectroscopy (XPS) measurements are performed to investigate the chemical composition and nitrogen content of MoS2/g-C3N4 nanosheets. The N1s spectrum shows three nitrogen components, with the most prominent one being pyridinic-N (398.9 eV) and the other two pyrrolic-N (400.1 eV) and graphitic-N (401.3 eV), respectively [2-4]. The pyridinic-N is the major one accounting for more than half of the overall nitrogen content (42%). The C1s spectra show three deconvoluted peaks that could be assigned to graphite like sp2 carbon (284.8 eV), C-N (285.1 eV) and O-C=O (290.2 eV), respectively [3-4]. The Mo3d spectrum shows the expected Mo3d5/2 (229.8 eV), Mo3d3/2 (232.9 eV) and Mo+6 species (236.1 eV) as commonly observed in partially oxidized MoS2 complexes [5-6]. The S2p spectrum splits into four peaks located at 162.3, 163.4, 163.9, 169.0 eV, which are assigned to S2p3/2, S2p1/2, S-2, and S+4, respectively [5-6]. To our knowledge, this is the first example of utilizing MoS2/g-C3N4 composite as a sulphur host for high performance lithium sulphur batteries. Previously, Ghazi and co-workers[7] had utilized MoS2/Celgard separator as a polysulphide barrier which delivered a reversible capacity of 401mAh/g at 0.5C after 600 cycles with 0.083% capacity decay/cycle and an initial discharge capacity of 550mAh/g at 1C rate. Recently Yu and co-workers [8] reported the utilization of ultrathin mesoporous graphitic carbon frameworks as a sulphur host which showed improved cycling performance with 0.044% capacity decay/ cycle after 400 cycles at 2C and good rate capability by delivering initial discharge capacity of 430mAh/g at 6C. Electrochemical testing of MoS2/g-C3N4 composite showed remarkable cycling and rate performance by delivering specific discharge capacity of around 674, 612 and 510mAh/g at 2, 4 and 8C rate with capacity retention of 80% (0.049% decay/cycle), 77%(0.057% decay/cycle) and 88%(0.03% decay/cycle)respectively, after 400 cycles as shown in the figure. This work demonstrates the development of flexible 2D cathode materials beyond graphene for superior performance of lithium-sulphur batteries.

Highly anisotropic, multichannel wood carbon with optimized heteroatom doping for supercapacitor and oxygen reduction reaction

Rational architectural design of highly active and stable electrochemical materials is desirable for sustainable energy technologies but remains great challenges. Herein, inspired by inherent anisotropic structure for high-efficient ions transport in natural wood, we use basswood as precursor and present a low-tortuosity, multichannel, mesoporous carbon framework for both supercapacitor and oxygen reduction reaction (ORR) applications. With initial heteroatom embedment, followed by ammonia activation, surface functionalities, porous structures and specific surface areas of the wood carbons are simultaneously optimized. Accordingly, the as-prepared materials deliver much enhanced electrochemical performances as self-supported supercapacitor electrodes with remarkable specific capacitances and high energy/power density. Simultaneously, the resultant wood carbons also exhibit superior ORR performances with a half-wave potential of 0.86 V (vs. reversible hydrogen electrode) in alkaline media, in conjunction with superb methanol cross-over tolerance and long-term stability, which then served as suitable and durable air-cathode catalysts for Zn-air battery. The results of this work open up new avenues for facile and rational design of structure-featured carbon materials from earth-abundant biomass for practical energy storage and conversion utilizations.

Ultrathin WS2 nanosheets vertically embedded in a hollow mesoporous carbon framework – a triple-shell structure with enhanced lithium storage and electrocatalytic properties

HTSHNs WS2/C with ultrathin WS2 nanosheets vertically embedded in HMCSs provide abundant active sites, high conductivity and superior structural stability.

Mesoporous 3D carbon framework encapsulated manganese oxide nanoparticles as biocompatible T1 MR imaging probe

Magnetic resonance imaging (MRI) is one of the widely used medical diagnostic techniques due to its non-invasive nature, higher resolution and efficiency in soft tissue imaging. MRI contrast agents with high relaxivity and biocompatibility are of great importance for successful clinical diagnosis. Manganese based substances have emerged as new class of MR imaging agents due to their impressive contrast ability. In this study, we have reported development of manganese oxide (Mn3O4) nanoparticles encapsulated in mesoporous 3D carbon framework (CF) functionalized by polyethylene glycol (PEG) as T1 based MRI contrast agent. PEG functionalization endowed solubility and stability of the contrast agent in water which are highly essential traits of MRI contrast agents. The carbon framework provided excellent biocompatibility by ruling out possibility of metal ion exposure (offering suitability for in vivo application) and simultaneously enabled water exchange through its pores which led to T1 contrast improvement. The as-prepared PEG modified manganese oxide@CF nanosystem exhibited paramagnetic behaviour at room temperature, enhanced water proton relaxation and facilitated contrast of T1-weighted MR images.

Architecting a Mesoporous N-Doped Graphitic Carbon Framework Encapsulating CoTe2 as an Efficient Oxygen Evolution Electrocatalyst.

To improve the efficiency of cobalt-based catalysts for water electrolysis, tremendous efforts have been dedicated to tuning the composition, morphology, size, and structure of the materials. We report here a facile preparation of orthorhombic CoTe2 nanocrystals embedded in an N-doped graphitic carbon matrix to form a 3D architecture with a size of ∼500 nm and abundant mesopores of ∼4 nm for the oxygen evolution reaction (OER). The hybrid electrocatalyst delivers a small overpotential of 300 mV at 10 mA cm-2, which is much lower than that for pristine CoTe2 powder. After cycling for 2000 cycles or driving continual OER for 20 h, only a slight loss is observed. The mesoporous 3D architecture and the strong interaction between N-doped graphitic carbon and CoTe2 are responsible for the enhancement of the electrocatalytic performance.

Improved Lithium-Ion and Sodium-Ion Storage Properties from Few-Layered WS2 Nanosheets Embedded in a Mesoporous CMK-3 Matrix.

An integrated WS2 @CMK-3 nanocomposite has been prepared by a one-step hydrothermal method and then used as the anode material for lithium-ion and sodium-ion batteries. Ultrathin WS2 nanosheets have been successfully embedded into the ordered mesoporous carbon (CMK-3) framework. Owing to the few-layered nanostructure of WS2 , as well as the high electronic conductivity and the volume confinement effect of CMK-3, the material shows larger discharge capacity, better rate capability, and improved cycle stability than pristine WS2 . When tested in lithium-ion batteries, the material delivers a reversible capacity of 720 mA h g-1 after 100 cycles at a current density of 100 mA g-1 . A large discharge capacity of 307 mA h g-1 is obtained at a current density of 2 A g-1 . When used in sodium-ion batteries, the material exhibits a capacity of 333 mA h g-1 at 100 mA g-1 without capacity fading after 70 cycles. A discharge capacity of 230 mA h g-1 is obtained at 2 A g-1 . This excellent performance demonstrates that the WS2 @CMK-3 nanocomposite has great potential as a high-performance anode material for next-generation rechargeable batteries.

Cu, Co‐Embedded N‐Enriched Mesoporous Carbon for Efficient Oxygen Reduction and Hydrogen Evolution Reactions

Rational synthesis of hybrid, earth‐abundant materials with efficient electrocatalytic functionalities are critical for sustainable energy applications. Copper is theoretically proposed to exhibit high reduction capability close to Pt, but its high diffusion behavior at elevated fabrication temperatures limits its homogeneous incorporation with carbon. Here, a Cu, Co‐embedded nitrogen‐enriched mesoporous carbon framework (CuCo@NC) is developed using, a facile Cu‐confined thermal conversion strategy of zeolitic imidazolate frameworks (ZIF‐67) pre‐grown on Cu(OH)2 nanowires. Cu ions formed below 450 °C are homogeneously confined within the pores of ZIF‐67 to avoid self‐aggregation, while the existence of CuN bonds further increases the nitrogen content in carbon frameworks derived from ZIF‐67 at higher pyrolysis temperatures. This CuCo@NC electrocatalyst provides abundant active sites, high nitrogen doping, strong synergetic coupling, and improved mass transfer, thus significantly boosting electrocatalytic performances in oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). A high half‐wave potential (0.884 V vs reversible hydrogen potential, RHE) and a large diffusion‐limited current density are achieved for ORR, comparable to or exceeding the best reported earth‐abundant ORR electrocatalysts. In addition, a low overpotential (145 mV vs RHE) at 10 mA cm−2 is demonstrated for HER, further suggesting its great potential as an efficient electrocatalyst for sustainable energy applications.

An Improved Li–SeS2 Battery with High Energy Density and Long Cycle Life

Selenium–sulfur solid solutions are a class of potential cathode materials for high energy batteries, since they have higher theoretical capacities than selenium and improved conductivity over sulfur. Here, a high‐performance cathode material by confining 70 wt% of SeS2 in a highly ordered mesoporous carbon (CMK‐3) framework with a polydopamine (PDA) protection sheath for novel Li–Se/S batteries is reported. With a relatively high SeS2 mass loading of 2.6–3 mg cm−2, the CMK‐3/SeS2@PDA cathode exhibits a high capacity of &gt;1200 mA h g−1 at 0.2 A g−1, excellent C‐rate capability of 535 mA h g−1 at 5 A g−1, and prolonged life over 500 cycles. Benefitting from the unique advantages of SeS2 and the rationally designed host framework, this new cathode material demonstrates a feasible strategy to overcome the bottlenecks of current Li–S systems for high energy density rechargeable batteries.