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Although cobalt nitride (CoN)-based nanomaterials have been widely designed as advanced oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR) catalysts, the continuous consumption of lithium-ion batteries (LIBs) has led to a high price of cobalt metal. Therefore, in the future, recycling valuable Co elements from spent devices and boosting their service efficiency will inevitably promote the utilization of Co-based materials in water splitting and zinc-air batteries (ZABs). Herein, we realize the Co recycling from spent LIBs by a simple hydrometallurgy method. Under the assistance of hexamethylenetetramine and polystyrene spheres, after the hydrothermal and pyrolysis treatment in the NH 3 atmosphere, the as-reclaimed cobalt oxalates were successfully transformed into novel three-dimensional (3D) CoN nanoflowers (denoted as CoN NFs). Benefiting from the unique 3D flower-like architectures, intrinsic high conductivity, large surface area, uniformly dispersed CoN nanoparticles, and the synergistic effect between Co 3 N and CoO phases, the 3D flower-like CoN NFs exhibited excellent OER catalytic activity. The performance was much better than commercial RuO 2 in the 1.0 M KOH solution. Furthermore, the CoN NFs-based water splitting cell needed a voltage of 1.608 V to achieve the current density of 10 mA cm -2 , which is even 16 mV smaller than that of Pt/C||RuO 2 benchmark (1.624 V). Meanwhile, the CoN NFs-derived ZAB exhibited a high peak power density of 107.3 mW cm -2 (vs. 103.2 mW cm -2 of Pt/C-RuO 2 -based ZAB) and a low charge-discharge voltage gap (0.93 V vs. 1.43 V of Pt/C-RuO 2 -based ZAB). Due to the excellent structural and elemental stabilities, the corresponding water splitting cell and ZAB had outstanding durability. This work successfully explored an advanced industrial chain from recycling Co metal in spent devices to designing the high-efficiency HER/OER/ORR electrocatalysts for advanced water splitting devices and ZABs. This will further promote the value-added utilization of valuable Co metal in various energy storage or conversion devices., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Designing two-dimensional (2D) porous carbon nanosheets is expected to boost the water splitting efficiency of low-cost iron (Fe) and cobalt (Co)-based catalysts. Nevertheless, the aggregations, tedious preparation procedures, and expensive precursors for synthesizing 2D porous carbon nanosheets have hindered their widespread application. Herein, for the first time, we developed a low-cost method for large-scale and rapid synthesis of the three-dimensional (3D) hierarchically porous architectures self-assembled by the ultrafine FeCo nanoparticles embedded and boron/nitrogen-codoped 2D porous carbon nanosheets (denoted as FeCo@BNPCNS). The optimal FeCo@BNPCNS-900 exhibited abundant porous channels, a large surface area, and vast carbon edges/defects. Therefore, 8.10 at% electrochemically active boron (B)/nitrogen (N) centers were doped into the porous carbon nanosheets. In an alkaline solution, the optimal FeCo@BNPCNS-900 nanosheets revealed excellent hydrogen evolution reaction (HER) electrocatalytic activity, surpassing commercial 20 wt% Pt/C. For instance, the HER potential at 10 mA cm -2 [-50.6 mV vs. reversible hydrogen electrode (RHE)] of FeCo@BNPCNS-900 was even 19.3 mV more positive than that of commercial 20 wt% Pt/C (-69.9 mV vs. RHE). Meanwhile, its oxygen evolution reaction (OER) catalytic activity was just a little worse than ruthenium oxide (RuO 2 ). The water electrolysis cell of FeCo@BNPCNS-900 nanosheets just required a small voltage of 1.589 V for full water splitting to achieve 10 mA cm -2 , even 70.3 mV more negative than that of the state-of-the-art 20 wt% Pt/C||RuO 2 benchmark (1.660 V) with outstanding stability. The perfect 3D hierarchically porous and honeycomb-like architecture, abundant porous channels/mesopores, and uniformly dispersed electrocatalytically active sites on FeCo@BNPCNS-900 nanosheets were responsible for the outstanding water splitting performance. Finally, this study provides an efficient strategy for the large-scale, rapid, and low-cost synthesis of 2D porous carbon nanosheets without using any template, surfactant, or expensive precursors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Designing two-dimensional (2D) porous carbon nanosheets is a promising strategy for enhancing the water-splitting activities of non-noble metal catalysts. In this study, we developed a novel method for synthesizing the novel three-dimensional (3D) hierarchically porous iron-nickel (FeNi) nanoparticles encapsulated in boron (B) and nitrogen (N)-codoped porous carbon nanosheets (denoted as FeNi@BNPCNS). Owing to the advantages of morphology and structure of B and N, 10.31 atom % of B/N active centers were successfully doped into the optimal FeNi@BNPCNS-800 nanosheets. FeNi@BNPCNS-800 exhibited better hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalytic activities than control catalysts in an alkaline solution. However, the HER and OER electrocatalytic activities of FeNi@BNPCNS-800 were slightly lower than 20 wt% Pt/C and RuO 2 . The FeNi@BNPCNS-800||FeNi@BNPCNS-800 electrolyzer achieved 10 mA cm -2 at 1.514 V, which was 73 mV lower than that of 20 wt% Pt/C||RuO 2 electrolyzer (1.587 V). The perfect 3D honeycomb-like architectures, abundant mesopores/defects, and abundant electrocatalytic active sites were attributed to the outstanding water-splitting performances of FeNi@BNPCNS-800 nanosheets. This study provides an efficient strategy for the large-scale, rapid, and low-cost fabrication of 2D porous carbon nanosheets without using any template, surfactant, or expensive raw material, thus presenting a simple approach to design advanced non-noble metal electrocatalysts for water splitting., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Transition metal-nitrogen-carbon (MNC) type catalysts have been considered a promising alternative to noble metals for oxygen reduction reaction (ORR) electrocatalysis. Nevertheless, poor stabilities of MNC catalysts in acidic solutions limit their commercialization. In this study, we design and synthesize novel three-dimensional (3D) cobalt (Co) nanoparticles encapsulated in ultrahigh content of boron (B) and nitrogen (N) -doped hierarchically porous carbon nanofibers (denoted as Co@BN-PCNFs) by carbonizing the 3D acetic acid/cobalt nitrate/4-hydroxybenzeneboronic acid/polyvinylpyrrolidone precursor networks woven using electrospinning method under a nitrogen atmosphere. The optimal Co@BN-PCNFs-900 catalyst has abundant micro/mesopores and numerous topological defects and exhibits the largest surface area. Under the synergistic effect of oxygen-containing acetic acid molecules and the electrospinning technology, 5.87 at.% of B and 5.91 at.% of N atoms were doped into carbon nanofibers. Specifically, B/N electrocatalytic active centers (including BC 3 , pyridinic-N/CoNC, pyrrolic-N, and graphitic-N) of approximately 8.70 at.% were successfully introduced into the skeletons of Co@BN-PCNFs-900. In 0.1 M KOH, the ORR onset potential (E onset ) and half-wave potential (E 1/2 ) of Co@BN-PCNFs-900 were ∼ 64 and ∼ 63 mV, respectively, more positive than those of 20 wt% Pt/C. Additionally, in 0.5 M H 2 SO 4 , the ORR E onset and E 1/2 values of Co@BN-PCNFs-900 were only ∼ 11 and ∼ 7 mV, respectively, more negative than those of 20 wt% Pt/C. As the 3D hierarchically porous architectures, topological carbon edges, BC 3 , and partial NC/CoNC are relatively stable, the Co@BN-PCNFs-900 exhibits excellent stability toward ORR catalysis in both acidic and basic media. These favorable properties of Co@BN-PCNFs-900 nanofibers make them the best non-noble metal-based carbonaceous electrocatalysts for ORR in acidic electrolytes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

With high prices of precious metals (such as platinum, iridium, and ruthenium) and transition metals (such as cobalt and nickel), the design of high-efficiency and low-cost non-precious-metal-based catalysts using iron (Fe) and manganese (Mn) metals for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are critical for commercial applications of water splitting devices. In the study, without using any template or surfactant, we successfully designed novel cross-linked manganese borate (Mn 3 (BO 3 ) 2 ) and iron carbide (Fe 3 C) embedded into boron (B) and nitrogen (N) co-doped three-dimensional (3D) hierarchically meso/macroporous carbon nanowires (denoted as Fe x Mn y @BN-PCFs). Electrochemical test results showed that the HER and OER catalytic activities of Fe 1 Mn 1 @BN-PCFs were close to those of 20 wt% Pt/C and RuO 2 . For full water splitting, (-) Fe 1 Mn 1 @BN-PCFs||Fe 1 Mn 1 @BN-PCF (+) cell achieved a current density of 10 mA cm -2 at a cell voltage of 1.622 V, which was 14.2 mV larger than that of (-) 20 wt% Pt/C||RuO 2 (+) benchmark. The synergistic effect of 3D hierarchically meso/macroporous architectures, excellent charge transport capacity, and abundant active centers (cross-linked Mn 3 (BO 3 ) 2 /Fe 3 C@BNC, BC 3 , pyridinic-N, MNC, and graphitic-N) enhanced the water splitting catalytic activity of Fe 1 Mn 1 @BN-PCFs. The (-) Fe 1 Mn 1 @BN-PCFs||Fe 1 Mn 1 @BN-PCF (+) cell exhibited excellent stability owing to the superior structural and chemical stabilities of 3D hierarchically porous Fe 1 Mn 1 @BN-PCFs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

In the development of water splitting, the sluggish electrocatalytic kinetics of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) have restricted their energy conversion efficiencies. Along with the continuous rise in the prices of noble metals and transition metals (such as cobalt and nickel), constructing high-efficiency HER/OER catalysts based on low cost transition metals, such as iron and manganese, is becoming more meaningful in developing industrialized water splitting devices. In this paper, in the absence of a template or active agent, three-dimensional, hierarchically porous Fe x Mn y nanoparticles (NPs) were embedded and nitrogen-doped carbon materials (denoted as Fe x Mn y @NC; x:y, representing the molar ratio of Fe:Mn) were successfully prepared via pyrolysis of corresponding precursors containing different metallic salt components. Various morphological, structural, and chemical characterization analysis demonstrate that at an Fe:Mn molar ratio of 3:1, the optimal Fe 3 Mn 1 @NC material shows high graphitization degree, rich mesoporous structures, a large surface area, and abundant carbon defects/edges, which promote the uniform dispersion of pyridinic-N (pyridinic-N-metal), graphitic-N, carbon oxygen bonds (CO), manganese oxide (MnO) nanocrystals, and Fe 3 C NPs-embedded, N-doped carbon sheet (Fe 3 C@NC) active sites. In alkaline conditions, the HER onset potentials (E onset ) and potentials recorded at 10 mA cm -2 (E 10 ) of the optimal Fe 3 Mn 1 @NC are just 84.8 and 156 mV more negative than those of 20 wt% platinum carbon (Pt/C). Meanwhile, the OER E onset and E 10 values of the optimal Fe 3 Mn 1 @NC are just 8 and 18.7 mV more positive than those of RuO 2 . Furthermore, optimized Fe 3 Mn 1 @NC catalysts were assembled into a water splitting cell, where the catalytic current density achieves 10 mA cm -2 at a low voltage of 1.6287 V (with superior catalytic stability), which is just 24.9 mV higher than that of the (-) 20 wt% Pt/C||RuO 2 (+) benchmark (1.6038 V) under the same conditions. This work describes the regulating efficiency of Mn toward growing mesopores and opens new possibilities for the development of novel carbonaceous catalysts with excellent hydroxide catalytic efficiencies based on low cost Mn/Fe elements., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Herein, a simple and fast laser-assisted coupling method is used for preparation of rod-like carbon-coated Mo/MoO 2 hybrids at room temperature and air environment. Under high energy of laser and reductive atmosphere caused by precursor decomposition, Mo-polydopamine complex-wrapped MoO 3 rods are quickly converted into nitrogen-doped carbon-coated Mo/MoO 2 rods. Carbon-coated Mo/MoO 2 exhibits high surface area, uniform metal dispersion and appealing hydrogen evolution reaction (HER) catalytic performance in a wide pH range. Carbon-coated Mo/MoO 2 shows overpotential of 134, 108 and 164 mV to deliver current density of 10 mA cm -2 under alkaline, acidic and neutral solution, respectively. Theoretical calculation demonstrates that combination of Mo and MoO 2 into Mo/MoO 2 composite favors the dissociation of water and adsorption of hydrogen. This study not only provides a high-efficiency strategy for preparation of electrocatalysts but also give guidance for development of hybrid electrocatalysts for HER., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

It is highly desirable to develop durable and advanced electrocatalysts for pH-universal hydrogen evolution reaction (HER). While it makes much progress so far, the development of an environmental-friendly and cost-effective method to upgrade earth-abundant biomass into high value-added products still remains a major challenge. Thermal pyrolysis method which requires high pyrolysis temperature and long synthesis period is considered as a general method for preparation of carbon-based electrocatalysts. In view of this, ruthenium, nitrogen co-doped porous carbon (Ru@CN) is synthesized by laser conversion method at room temperature using cheap and renewable biomass honey as green carbon source. By controlling the loading of Ru and laser power, the electrocatalytic activities of as-prepared electrocatalysts can be adjusted effectively. Because of the advantage of rich Ru 0 and Ru-N sites, the synthesized 0.04-Ru@CN-6 with Ru loading amount of 2.66 wt% exhibits a preferable electrocatalytic activity toward HER under all-pH conditions. Especially in alkaline solution, the optimal 0.04-Ru@CN-6 exhibits a small overpotential (11 mV) at 10 mA cm -2 current density, which is even much better than commercial 20 wt% Pt/C (37 mV). This strategy reported here may be a feasible and unique approach to synthesis and design of high-performance as well as cost-effective all-pH HER electrocatalyst., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Rational design and synthesis of multifunctional electrocatalysts with high-efficient activity and robust stability toward the oxygen reduction reaction (ORR), hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are highly desirable, but remain a challenging step. Herein, a novel hollow bimetallic carbide/nitrogen-doped carbon nanotube (Co 6 Mo 6 C 2 @NCNT) is successfully synthesized through the simple pyrolysis of polypyrrole (PPy)-supported metal-organic framework (MOF) composite. Remarkable characteristics of the large surface area, hollow and porous structure, rich active sites and synergistic effect between Co 6 Mo 6 C 2 and NCNT arouse high catalytic efficiency. Notably, the Co 6 Mo 6 C 2 @NCNT presents excellent ORR catalytic activity (a high half-wave potential of 0.875 V vs. reversible hydrogen electrode (RHE) and diffusion-limited current density of 6.22 mA cm -2 ) via a four-electron pathway, together with outstanding stability and methanol tolerance over commercial Pt/C in 0.1 M KOH solution. The composite also exhibits superior HER performance, delivering a low overpotential of 122.14 mV at current density of 10 mA cm -2 , as well as good catalytic performance for OER in 1.0 M KOH solution. This work may provide some insight in design multifunctional electrocatalysts derived from MOF with advanced performance for sustainable energy technologies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Ultrafine Co 7 Fe 3 nanoparticles embedded in nitrogen-doped porous carbon nanosheets (denoted as Co 7 Fe 3 /NPCSs) are successfully synthesized by utilizing porous plant tissue as a precursor. The morphological, structural, and chemical contents of the Co 7 Fe 3 /NPCSs and other control samples are analyzed by X-ray (powder) diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption-desorption, Raman spectroscopy, inductively coupled plasma (ICP), and X-ray photoelectron spectroscopy (XPS) techniques. The glucose oxidation and detection performances of each catalyst are evaluated by using cyclic voltammetry and chronoamperometry. The experimental results demonstrate that the electrocatalytic abilities of the resultant catalysts toward glucose oxidation decrease in the order of Co 7 Fe 3 /NPCSs > Co/NPCSs > CoFe/NPCSs > Fe 2 C-Co 3 Fe 7 /NPCSs > Fe 2 C/NPCSs. The experimental results prove that a small number of Fe atoms in Co 7 Fe 3 can increase the number of active Co 4+ sites. Meanwhile, the ultrafine Co 7 Fe 3 nanoparticles uniformly dispersed along the porous carbon nanosheets' surfaces, which further improved the dispersion of the abundant electrochemically available active sites. Due to the synergistic effect of the hierarchical porous structures, high-density active sites and excellent electron conductivity, the optimal Co 7 Fe 3 /NPCSs display the best glucose detection efficiency of all the catalysts examined. For instance, the Co 7 Fe 3 /NPCSs exhibit large sensitivity values (795.28 µA cm -2 mM -1 between 0.001 and 2.20 mM and 401.98 μA cm -2 mM -1 between 2.20 and 14.00 mM), a rapid response time (2.2 s), a low detection limit (1.0 µM), excellent anti-interference toward electroactive molecules, a perfect reproducibility and a superior long-term stability. The Co 7 Fe 3 /NPCSs also exhibit a satisfying efficiency for glucose detection in human serum samples. Finally, our low-cost synthetic strategy can advance research used for designing 3D hierarchical meso/macroporous noble-metal-free catalysts without any tedious steps or templates., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Developing high-efficiency catalysis electrodes towards both HER (hydrogen evolution reaction) and OER (oxygen evolution reaction) is critical to the popularity and practical application of devices for conversion and storage of clean and renewable hydrogen energy by overall water splitting. In this paper, a series of transition metal alloy nanoparticles embedded hierarchically porous carbon nanosheets (denoted as Fe x Co y @PCNSs) have been successfully designed and synthesized. After optimizing the metallic contents in Fe x Co y alloy, Fe 3 Co 7 @PCNSs displays superior water electrolysis performances compared to other control samples and previously reported non-noble metal catalysts. This advance is mainly due to the synergistic effect of increased carbon edges exposure, abundant accessible active sites, and improved electron/mass transport capability of 3D hierarchically porous architecture. More importantly, when Fe 3 Co 7 @PCNSs is applied as both cathode and anode in a two-electrode cell for carrying out the overall water splitting process, it just needs the corresponding cell voltages of 1.667 and 1.707 V to attain the 10 and 20 mA cm -2 current densities respectively. The synthesis of Fe 3 Co 7 @PCNSs confirms the importance of Fe and Co elements in designing catalyst structures. The electrochemical measurements further display the key roles of structural features and metal alloy@C active sites for boosting water splitting performances., (Copyright © 2018. Published by Elsevier Inc.)

Nonprecious-metal electrocatalysts have been intensively investigated, but how to keep a balance between their sustainability and competitive performance for the oxygen reduction reaction (ORR) is still a big challenge for energy applications. In this work, a type of bimetal- and nitrogen-codoped mesoporous carbon electrocatalyst (FeCo-N/C-800) was successfully synthesized via a simple hydrothermal method, followed by a calcination process at 800 °C in nitrogen atmosphere and an acid-etching process. The obtained FeCo-N/C-800 can act as a high-performance ORR catalyst with high onset and half-wave potentials (0.94 and 0.85 V), a large limiting current density (5.94 mA cm -2 ) and a four-electron reaction process in 0.1 M KOH solution, which can be comparable with commercial Pt/C catalyst. Additionally, the FeCo-N/C-800 exhibited superior long-term durability and high methanol tolerance. The excellent electrocatalytic performance of the FeCo-N/C-800 can be ascribed to the mesoporous structure (bimodal pores system), the synergetic interaction of the multiple ORR active sites, suitable N-doping level and the highly conductive carbon matrix. These structural features can promote efficiently the mass and electron transfer, provide abundant active sites for the adsorption and reaction of oxygen molecules, and thus improve the reaction kinetics. The present study not only provides a strategy for the synthesis of carbon-based electrocatalyst with high ORR catalytic activity and stability, but also demonstrates that the bimetal- and nitrogen-codoped carbon materials could be a class of competitive candidate for non-noble metal-based electrocatalysts., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Exploring highly active, inexpensive and robust electrocatalysts for oxygen reduction reaction (ORR) is of great significance as a competitive alternative to noble metal-based catalysts in energy conversion and storage devices. In the present study, we design a novel ORR electrocatalyst of iron-cobalt (FeCo) alloy nanoparticles embedded on N-doped porous carbon nanofibers (FeCo@PCNF-T) by electrospinning of [Polyacrylonitrile (PAN)/Prussian blue analogues/CaCO 3 ] and post-calcination treatment. The obtained catalysts with bimetallic active sites show unique three-dimensional (3D) hierarchical meso/macropores structures. FeCo alloy nanoparticles are encapsulated into graphitic carbon that can increase stability and provide additional catalytic active sites. Under the optimized condition, FeCo@PCNF-800 displays excellent ORR electrocatalytic activity in alkaline solutions, with a more positive half-wave potential (E 1/2 of 0.854 V vs RHE) and larger limited-diffusion current density (j of 6.012 mA cm -2 ) than those of 20 wt% Pt/C (E 1/2 of 0.849 V and j of 5.710 mA cm -2 ). In addition, FeCo@PCNF-800 also exhibits comparable ORR electrocatalytic activity in acidic solutions to those of 20 wt% Pt/C with onset potential and half-wave potential as more positive as 0.843 V vs RHE and 0.739 V vs RHE, respectively. Moreover, FeCo@PCNF-800 exhibits excellent tolerance towards methanol, stability and a four-electron pathway in both basic and acidic solutions. The excellent ORR electrocatalytic activity performance of FeCo@PCNF-800 is attributed to the synergistic effect of the FeCo alloy nanoparticles and N-doped porous carbon nanofibers. The synergistic effect can improve the mass and charge transport capability and increase active sites of FeCo-N-C. Furthermore, this work offers a new insight for the reasonable design and development of efficient non-noble metal electrocatalysts for challenging electrochemical energy-related technologies., (Copyright © 2018 Elsevier Inc. All rights reserved.)

In this paper, polyvinylpyrrolidone (PVP) and 4-hydroxybenzeneboronic acid (o-HPBA) are polarized in alkaline solution and then employed as boron (B) and nitrogen (N) sources. Fe(AC) 2 /o-HPBA/PVP/DMF(N,N-Dimethylformamide) slurries are first electrospunned into three-dimensional (3D) networks. Due to the electrostatic repulsion between negatively charged O - groups surrounding N and B atoms, N and B atoms can be kept far away from each other. Upon optimizing o-HPBA dosages, the maximum amount of isolated B and N atoms are successfully doped into the 3D porous iron carbide (Fe 3 C) embedded B and N co-doped carbon fibers (Fe 3 C@B 1.0 NPCFs) networks with tiny BN clusters. Electrochemical measure results demonstrate that Fe 3 C@B 1.0 NPCFs exhibit much better oxygen reduction reaction (ORR) activity than 20 wt% Pt/C in alkaline electrolyte. In acidic electrolyte, Fe 3 C@B 1.0 NPCFs also displays ORR activity comparable to Pt/C (its onset and half-wave potentials are just 40 and 50 mV more negative than those of Pt/C). Moreover, Fe 3 C@B 1.0 NPCFs show better stability and methanol tolerance ability than Pt/C for ORR in both alkaline and acidic solutions. This work opens new avenues for intentionally preventing the malignant combination of B and N atoms and boosting the electrocatalytic activity of B and N co-doped and Fe 3 C embedded carbon catalysts., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Porphyrinic iron metal-organic framework (pFeMOF) was combined with different kinds of carbon matrices, including porous graphene (PG), ordered mesoporous carbon (OMC) and macroporous carbon (MPC) via a simple one-step hydrothermal method. The introduction of carbon substrates improves the electrical conductivity and stability of pFeMOF. The presence of carbon also reduces the size of pFeMOF crystallites, leading to more active sites. The catalysts were used to electrocatalysis of hydrogen evolution reaction (HER) and the reduction of hydrogen peroxide (H 2 O 2 ). Electrochemical measurements show that pFeMOF/PG has better electrocatalytic efficiency than pFeMOF/OMC, pFeMOF/MPC and pFeMOF. The HER on pFeMOF/PG displays a small onset potential of -34.37 mV vs. reversible hydrogen electrode (RHE), a low Tafel slope of 73.06 mV dec -1 , a small over-potential of 154.71 mV at 10 mA cm -2 . The catalytic effect for H 2 O 2 is also satisfied. The linearity range of H 2 O 2 is as wide as 5-4310 μM, and the sensitivity is as high as 77.38 μA mM -1 . Such splendid performances may be attributed to the crumpled structure of PG leading to evenly and smaller pFeMOF. Furthermore, abundant hierarchical pores of pFeMOF/PG result in larger electrochemically surface areas. Our work may provide a new approach to design efficient non-precious metal catalysts., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Graphene (GR) is one of the most promising candidates for utilization in the electroanalytical field because of its superior electrocatalytic activity, excellent electronic conductivity, and high chemical stability. However, the GR sheets usually tend to stack together with π-π interaction. The spontaneous stacking leads to the aggregation of the GR sheets and imposes a negative feedback in the surface area of the GR, which obviously limits its electrochemical application. In this study, nitrogen-doped porous GR (NPGR) with different pore sizes is prepared by using silica (SiO 2 ) as a template. The NPGR exhibits high surface area and porous structure, fulfilling the requirement for supporting materials. Being a support, the structural uniqueness and N dopants of NPGR facilitate the deposition of Pt nanoparticles (Pt NPs). The Pt NPs/NPGR composites integrate the structural properties of NPGR and catalytic properties of Pt NPs. A selective and sensitive electrochemical sensor was successfully developed for sensitive determination of Tadalafil (TAD), showing a concentration range of 1.30-488.9μM and limit of detection of 0.268μM., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Nitrogen-doped graphene (N/GR) has been considered as active metal-free electrocatalysts for oxygen reduction reaction (ORR). However, the nitrogen (N) doping efficiency is very low and only few N atoms are doped into the framework of GR. To boost the N doping efficiency, in this work, a confined pyrolysis method with high N doping efficiency is used for the preparation of cobalt nanoparticles/nitrogen-doped GR (Co/N/GR). Under the protection of SiO 2 , the inorganic ligand NH 3 in cobalt amine complex ([Co(NH 3 ) 6 ] 3+ ) is trapped in the confined space and then can be effectively doped into the framework of GR without the introduction of any carbon residues. Meanwhile, due to the redox reaction between the cobalt ions and carbon atoms of GR, Co nanoparticles are supported into the framework of N/GR. Due to prevention of GR layer aggregation with SiO 2 , the Co/N/GR with high dispersion provides sufficient surface area and maximum opportunity for the exposure of Co nanoparticles and active sites of N dopant. By combination of enhanced N doping efficiency, Co nanoparticles and high dispersion of GR sheets, the Co/N/GR is remarkably active, cheap and selective noble-metal free catalysts for ORR., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The electrochemical properties of boron-doped ordered mesoporous carbon (BOMC) as an electrode material and Pt catalyst support were investigated. The BOMC was synthesized and its structure was examined by transmission electron microscopy (TEM), scanning electron microscopy, nitrogen adsorption-desorption, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). More defective sites were introduced into OMC by the doping of boron. Six electroactive compounds were employed to investigate their electrochemical responses on BOMC and OMC modified glassy carbon electrodes. The BOMC, with more defective sites, exhibited high activity toward the electroactive compounds. The property of BOMC of supporting platinum nanoparticle catalyst was examined. Pt nanoparticles were loaded onto BOMC and OMC, and this was confirmed by TEM, XPS and thermogravimetric analysis. Pt nanoparticles with an average diameter of 2.62 nm were deposited on BOMC. The doping of boron into OMC facilitates the dispersion of Pt nanoparticles. Pt nanoparticles supported on BOMC (Pt-BOMC) and Pt nanoparticles supported on OMC (Pt-OMC) were electrochemically characterized. The electrocatalytic activity of Pt-BOMC toward methanol oxidation reaction was compared with that of Pt-OMC and commercial Pt-C catalyst. The results show that the electrocatalytic activity of BOMC is significantly higher than that of other used catalysts., (Copyright © 2014 Elsevier Inc. All rights reserved.)