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This paper introduces a facile method to develop core-shell nanocomposite Cu/(Cu 2 O/CuO) through gradually oxidation on Cu nanocomposite precursors. As-prepared catalyst exhibited excellent catalytic activity in the reaction of water oxidation reaction (WOR). Comparing with the reported catalyst, Cu/(Cu 2 O/CuO) posed one of the highest O 2 evolution around 7700 μmol g-1·h-1. By analyzing the composition of catalysts in each reaction stages, the evolution pathway of Cu towards Cu 2 O/CuO and the different roles of each component in catalytic water oxidation reactions were deeply studied. In presence of high conductive Cu element and excellent light absorption Cu 2 O, the photo generated electron and holes can be effectively separated and greatly improve the efficiency of the catalyst. The evolution process and synergistic effects of the three components play a crucial role in improving photocatalytic efficiency, which promoting the nanocomposite to be a highly efficient core-shell catalyst for WOR. This paper presents the evolution of a highly active photocatalytic water oxidation catalyst with no photosensitizers. [Display omitted] • Cu/(Cu 2 O/CuO) core-shell nanocomposite exhibits a a high oxygen production rate of 7700 μmol·g-1·h-1. • The relationship between the evolution of Cu to Cu 2 O/CuO and the photocatalytic efficiency was explored. • Cu/Cu 2 O core-shell plays a crucial role in charge separation and dramatically increasing the catalytic efficiency. [ABSTRACT FROM AUTHOR]

In this paper, Ni x Cd y S composite photocatalysts were synthesized by using Ni-doped Cd–Co PBA as the precursor, which retains the advantages of PBA such as porous structure, large specific surface and highly dispersed metal active sites. The photocatalytic hydrogen production performance over Ni x Cd y S is three times higher than that of pure CdS with H 2 yield of 8.45 mmol g−1 h−1. The catalyst was analyzed by the UV/Vis absorption spectra, photoluminescence spectra, time-resolved photoluminescence spectra, transient photocurrent responses, electrochemical impedance spectra, Mott-Schottky test, etc. A series of characterization results prove that the electron-hole recombination rate, electrochemical resistance and band gap of nickel-doped CdS composites are obviously smaller than CdS, which are important factors to improve the photocatalytic hydrogen production performance. This work may provide some reference value for the fabrication of other functional materials using PBA as precursors. [Display omitted] • A synthesis strategy of excellent photocatalyst was developed by using PBA as precursor. • Hydrogen generation increase up to 5 times because interaction between NiS and CdS. • PBA based photocatalyst had large specific surface area. • NiS and CdS are uniformly compounded by a simple method. [ABSTRACT FROM AUTHOR]

The development of efficient non-noble-metal based catalysts for oxygen evolution reaction is the crucial issue to promote electrolytic water technology. Herein, an effective phosphorus-modified hollow porous Nickel-Cobalt oxides nanocube was prepared by thermal oxidation and partial phosphorization processes. The optimal P-NiO/NiCo 2 O 4 nanocube disclosed remarkable electrochemical activity for OER in 1.0 M KOH with a low overpotential of 290 mV at 10 mA cm−2, a low Tafel slope of 49.6 mV dec−1, and good long-life stability for 20 h. Based on the experimental and theoretical calculation results, the introduction of P was proved to be the key to the excellent electrochemical activity for OER. P doping could optimize the adsorption of the intermediates, decrease the energy barrier and change the rate-determining step. Meanwhile, the P-dopant could modulate the electronic structure and enhance the conductivity of NiO/NiCo 2 O 4. In addition, hollow, porous hybrid structure and oxygen vacancies could increase the number of active sites exposed, and facilitate the ion transport. The present work provides a valuable strategy to design transition-metal oxide based electrocatalysts with enhanced electrocatalytic performances by controlling partial P doping. Combine calcinations and controlled phosphorization to synthesize P-NiO/NiCo 2 O 4 nanocubes with remarkable electrochemical activity for OER. The experiment investigations and DFT calculations confirm in-situ partial phase transition not only can modify the electronic structure to improve the adsorption of the intermediates, but also enhance the conductivity of the electrocatalyst. [Display omitted] • Combine calcinations and controlled phosphorization to synthesize P-NiO/NiCo 2 O 4 nanocubes with remarkable electrochemical activity. • The introduction of P optimizes the adsorption of the intermediates, decrease the energy barrier and change the rate-determining step. • P doping modulates the electronic structure and enhances the conductivity of NiO/NiCo 2 O 4. • Hollow, porous hybrid structure and oxygen vacancies increase the number of active sites exposed, facilitate the ion transport. [ABSTRACT FROM AUTHOR]

ZIF-67 has been widely used in the field of photocatalytic, however, its insensitivity to visible light responsiveness has become a major difficulty in its further development. Studies have shown that the combination of cadmium sulfide (CdS) with ZIF-67 has enough potential to address this concern, but different morphologies and sizes of CdS have a great influence on the properties of composite materials. Therefore, this study focused on the physicochemical properties, photoelectric properties, and photocatalytic water-splitting properties of the CdS@ZIF-67 composites obtained by the combination of four different CdS morphologies and ZIF-67. It was found that the CdS@ZIF-67 composites had the performance of visible light region response without the use of photosensitizer, and the specific surface area of the composite was significantly improved. Among them, the nanoparticles CdS@ZIF-67 showed the most significant improvement in photocatalytic water splitting performance, and the optimal value reached 2.21 mmol•g−1•h−1. Based on the results of this study, it can be concluded that the zero-dimensional structure of CdS is more conducive to the performance improvement of composite materials, which provides favorable evidence for the later combination of semiconductor materials and metal-organic framework materials (MOFs). • By combining with CdS, ZIF-67 can get rid of the dependence on photosensitizer. • The effects of four morphologies of cadmium sulfide on the composites were studied. • The hydrogen production performance of CdS nanoparticle composite is 25.7 times that of CdS. • CdS nanoparticles is more conducive to the performance improvement of composite materials. [ABSTRACT FROM AUTHOR]

The electrolytic water-based hydrogen production demonstrates exceptional selectivity, minimal environmental impact, and superior purity of the generated hydrogen, thereby presenting promising prospects for a wide range of applications. The scarcity and high cost of Pt-based catalysts for industrial applications necessitate the development of low-cost, stable, and efficient transition metal electrocatalysts for hydrogen electrochemical precipitation (HER). In this paper, Mo 2 WS 6 nanorod array with honeycomb structure was successfully synthesized via one-step hydrothermal vulcanisation of transition metals W and Mo on nickel foam (NF) substrate. The honeycomb nanorod array structure exhibits enhanced specific surface area and abundant active sites, and the well-defined pore structure facilitates the transport of electrolyte and reactive substances. The intrinsic activity of the active sites is significantly enhanced by the synergistic effect of MoS 2 and WS 2 , facilitated by the formation of solid solution alloys. Excellent HER performance (η 10 =63 mV, η 100 =183 mV) was demonstrated in alkaline electrolyte (1.0 M KOH) with a corresponding Tafel slope of 93 mV dec−1. Furthermore, Mo 2 WS 6 exhibited excellent stability after undergoing 5000 cycles of charge/discharge and a constant voltage test lasting for 96 hours. This study provides a novel approach for facile synthesis of high-efficiency HER catalysts by a one-step hydrothermal method. • Mo 2 WS 6 solid solution alloy on nickel foam was synthesized via one-step hydrothermal method. • The 3D nanorod array structures were composed of stable and highly porous 2D nanosheets. • MoS 2 and WS 2 undergo electron transfer and synergistic interactions. • The catalyst exhibited low overpotential, rapid reaction kinetics, and excellent catalytic stability. [ABSTRACT FROM AUTHOR]

• A novel sheet-assembled flower-like Cd-MOF was synthesized. • The photocatalyst synthesized with MOF as precursor. • MOF based photocatalyst had large specific surface area. • The participation of MoS 2 reduced conduct band position and resistance. MOF based CdS-MoS 2 composite had strong photoresponse and rich catalytic sites because of the adjustable morphology and large specific surface area. The CdS-MoS 2 composite was synthesized by using the first synthesized Cd-MOF as the precursor. The hydrogen evolution activity was evaluated under simulated light source. The rate of photocatalytic hydrogen production can improve by 47 times for doping 2.5% (w/w) MoS 2 compare to pure CdS. The catalyst was analyzed by the UV/vis absorption spectra, photoluminescence spectra, time-resolved photoluminescence spectra, transient photocurrent responses, electrochemical impedance spectra, Mott-Schottky test, etc. The results revealed that the CdS-MoS 2 can greatly enhance the separation and transport efficiency of photogenerated carriers, and shift the position of conduction band for the catalyst, resulting significantly improve the production of hydrogen. This work provides a new strategy for manufacturing of photocatalyst by MOFs. [ABSTRACT FROM AUTHOR]

[Display omitted] • The gas/liquid products of C1-3 alcohols under photocatalysis were analyzed and summarized. • The relationship between the type of gas-liquid product and the structure of alcohol was analyzed. • Combined with the experimental results and DFT calculation, the possible gas/liquid product formation path under the present experimental conditions was predicted. Photocatalytic alcohols decomposition is of great significance for the preparation of hydrogen and alcohol derivatives. Among which, the improvement of the hydrogen purity is very important for the later utilization. In this study, the photocatalytic gas-liquid products and formation rules/paths with C1-3 alcohols as substrates were summarized, and the reaction mechanisms were inferred based on the cycle experimental data and DFT calculation. For gaseous products, CH 4 , CO, C 2 H 4 or C 2 H 6 were also detected during the photocatalyzed alcohols decomposition in addition to hydrogen. The hydrogen yield from photocatalytic decomposition of isopropyl alcohol reached 65.98 mmol/g within 6 h, and it was proved to be the best substrate for hydrogen production due to the lowest CO content. For liquid products, the selectivity of acetal produced from ethanol can up to 99%. This work could facilitate the development of photocatalytic alcohol decomposition to produce higher purity hydrogen coupled with higher value-added liquid products. [ABSTRACT FROM AUTHOR]

Ag 2 O modified CuO nanosheets (Ag 2 O/CuO) serve as both visible-light-driven water oxidation catalysts and visible light absorption centers. [Display omitted] • Ag 2 O/CuO nanosheets provides light-absorption centers in persulfate/NaOH system. • Ag 2 O/CuO catalyst has excellent water oxidation performance in a photosensitizer free system. • Ag 2 O/CuO nanosheets reduced the recombination of electron-hole pairs. • Mechanism of Ag 2 O/CuO nanosheets for water oxidation reaction was proposed. Semiconductors have been given immense attention for years regarding the use of photocatalytic water oxidation reaction (WOR) to reduce the potential barrier. However, some known semiconductors, such as TiO 2 and CuO, exhibit outstanding water oxidation activity in the UV light region. Therefore, it is important to explore the methods to expand the usage of these catalysts in the visible as well as IR regions. This study introduces a simple and facile chemical co-precipitation method to fabricate a sort of Ag 2 O-modified CuO nanosheets with excellent catalytic properties. The as-prepared Ag 2 O/CuO nanosheets exhibit a robust catalytic efficiency towards the visible-light-driven WOR. Due to the addition of Ag 2 O, the Ag 2 O/CuO nanosheets display photocatalytic activity. The total turnover number (TON) was 8.20 and when the effect of chemocatalytic activities was deducted, the TON, quantum yield (QY), and corresponding photonic efficiency (ζp) are 2.92, 0.65 %, and 0.33 %, respectively, which shows that Ag 2 O/CuO nanosheets possess water oxidation sites as well as light-absorption centers. With the synergy effect between the Ag 2 O and CuO, the catalyst efficiently reduced the recombination probability of photoexcited electrons and holes. Intriguingly, Ag 2 O/CuO nanosheets expanded the utility in the visible region as long as 765 nm, which evolved 95.89 % oxygen compared to that of the light cutting off at 420 nm. The insight into the WOR pathway is that surficial –OH groups of Ag 2 O/CuO nanosheets play a key role in this catalytic reaction. The mechanism of Ag 2 O/CuO nanosheets in the persulfate/NaOH system for water oxidation was consequently proposed according to electron spin resonance measurements and two radical scavengers (methanol and tert-butanol alcohol). This study offers useful guidance for developing difunctional water oxidation catalysts without photosensitizers. [ABSTRACT FROM AUTHOR]

Photocatalytic efficient hydrogen evolution from pure water with non-noble metal system has more practical application value. In this study, the ZnCdS/Co@CoO composite photocatalyst was prepared by a simple hydrothermal reduction method. The hydrogen evolution rate from water can reach to 793 μmol·g−1·h−1 in sacrificial agent-free system, and 5445 μmol·g−1·h−1 with Na 2 S and Na 2 SO 3 as sacrificial agent. The S-scheme heterojunction formed between ZnCdS and Co@CoO, as well as the abundant S vacancy were proved to be the key factors to effectively improve the photocatalytic performance. The study on the high hydrogen production efficiency and catalytic mechanism of ZnCdS/Co@CoO in sacrificial agent-free can provide ideas for the design and preparation of more efficient non-noble metal photocatalysts. [Display omitted] • The tiny ZnCdS/Co@CoO nanoparticles effectively shorten the electron transport distance. • The hydrogen yield can reach 793 μmol g−1 h−1 in sacrificial agent-free system. • The S vacancy acts as electron trap and avoids the recombination of electrons and holes. • The S-scheme heterojunction can be constructed between ZnCdS and Co@CoO. • The S-scheme heterojunction is favorable for the separation and transfer of electron-hole pair. [ABSTRACT FROM AUTHOR]

It is of great significance to explore a bifunctional catalyst that can produce both hydrogen and oxygen to accelerate the development of water-splitting technology. In this work, Co@CoO/NG was obtained via calcinating ZIF-67 and in-situ preparation process, which exhibited excellent performance (water oxidation AQE 10.22% at λ = 450 nm and oxygen production rate 543198 μmol g−1 h−1 and hydrogen production rate 330 μmol−1 g−1 h−1). A comprehensive analysis of SEM, XRD, TEM, UV–vis, EIS, and PL showed that Co@CoO/NG-7 prepared has a perfect skeleton and more crystal defects, which can provide more reactive sites. The core-shell structure Co@CoO has a synergistic effect with graphene, which is beneficial to the light absorption, separation of photo-generated charges. Meanwhile, cyclic experiments of water oxidation and water reduction showed that the catalyst exhibited high stability during the reaction process. This study has provided a universal strategy to design efficient bifunctional catalyst for water-splitting. Image 1 • Co@CoO/NG was synthesized by pyrolysis of ZIF-67 and in situ preparation. • Co@CoO/NG has both water reduction/oxidation catalytic activities. • The synergy of Co@CoO and carbon reduce the recombination of electrons and holes. • Co@CoO/NG exhibits excellent photocatalytic activity and stability. [ABSTRACT FROM AUTHOR]

This paper reports the novel design of shell-in-shell Ni3S4@Co9S8 double-shelled tube (DST) hierarchical structures with different shell compositions, and the subsequent attempt to fabricate these structures. We fabricated such unique shell-in-shell hierarchical structures through transition from isomorphic metal–organic framework core–shell structures of Ni-MOF-74@Co-MOF-74 in the presence of Na2S under solvothermal conditions. The as-prepared Ni3S4@Co9S8 DSTs demonstrated high specific capacity (up to 1257.4 F g−1 at a current density of 4 A g−1) with excellent charge–discharge reversibility (with 81.5% capacity retention after 1000 cycles), which is superior to that of the single-shelled Co9S8 tubes (337.8 F g−1 at 1 A g−1). The specific capacity of the prepared DST electrode also showed exceptional performance at a current density of 20 A g−1. Approximately 74.0% of the obtained value of the specific capacity was retained at 1 A g−1. This approach is a facile method to produce novel electrode materials for energy storage devices and a useful self-templated strategy for the preparation of multi-shelled hollow materials with different shell compositions for different functions. [ABSTRACT FROM AUTHOR]

This communication introduces a general approach toward the size/morphology-controlled synthesis of classical MOFs with 2-methylimidazole (2-MI) as a competitive ligand and a base to accelerate the nucleation of crystallization. A higher concentration of 2-MI and a suitable polarity and solubility of the solvent will accelerate the nucleation of the crystal, resulting in nanometer size particles. However, larger crystals can be obtained via the further growth of nanoparticles with prolonging the reaction time. Such a serendipitous discovery may inspire future researchers to design new MOF materials with desired structures. [ABSTRACT FROM AUTHOR]

Metal-organic framework materials (MOFs) have proven to be an excellent catalyst, but how to further improve their photocatalytic performance has become a challenge for researchers. In this study, we focus on the effect of two modulation strategies on the photocatalytic performance of MOFs, and 2-mercaptobenzimidazole (MBI) was introduced into the ZIF-67 structure by the solvent-assisted ligand exchange (SALE) method and the mixed ligand method, respectively, to modulate their photocatalytic performance. It was found that both strategies can successfully introduce MBI into the ZIF-67 structure, but the mixed ligand method tends to destroy the crystal morphology and structure of ZIF-67 and constructs a good deal of mesopores in the structure, which is detrimental to the improvement of catalytic performance. On the contrary, the SALE strategy can maintain the special crystal morphology and structure of ZIF-67 while introducing MBI, and can construct a suitable number of defects to enhance the photogenerated carrier transfer and separation efficiency of ZIF-67. Under the action of visible light, the ZIF-67- MBI catalysts obtained by the SALE method have the optimal photocatalytic activity, and their photocatalytic hydrogen and oxygen evolution rates can reach 6.14 mmol g−1 h−1 and 210 mmol g−1 h−1, respectively. This study demonstrates that the SALE method is a viable strategy to modulate the photocatalytic performance of MOFs and provides a reference for the construction of composites with excellent photocatalytic properties. • 2-mercaptobenzimidazole was introduced to modulate the performance of ZIF-67. • The effect of two modulation strategies was studied comparatively. • The mixed ligand method tends to destroy the crystal morphology and structure of ZIF-67. • The solvent-assisted ligand exchange method was proved to be a viable strategy. • The photocatalytic hydrogen evolution rates can reach 6.14 mmol g−1 h−1. [ABSTRACT FROM AUTHOR]

Transition-metal complexes, especially cobalt complexes, are used as precatalysts in homogeneous water oxidation catalysis. However, a practical method of identifying the effective active species in cobalt-complex homogeneous catalysts under highly oxidizing conditions have not yet been established. In this work, (H 3 O) 6 ·[Co 4 (H 2 O) 4 (HPMIDA) 2 (PMIDA) 2 ]·2H 2 O ( 1 ) was introduced, and its photocatalytic performance was evaluated. The compound exhibited effective water oxidation catalysis, with a turnover number of 661.5 at pH 9.0 using [Ru(bpy) 3 ](ClO 4 ) 2 as photosensitizers and sodium persulfate as sacrificial electron acceptor. Accordingly, 1 was used as target catalysts, and the active species was thoroughly investigated under catalytic conditions. The stability of 1 was further tested and confirmed by a series of experiments (cyclic voltammetry (CV), ultraviolet–visible (UV–vis) spectrometry, dynamic light-scattering (DLS), aging experiments, and extraction techniques). Results showed that 1 maintained its structural integrity under the given photocatalytic conditions. Furthermore, cathodic adsorptive stripping voltammetry and inductively coupled plasma-mass spectrometry were used to quantify the amount of Co 2+ ions released from 1 into borate buffer after oxidation. The pH dependence of the oxygen-evolution performance of 1 and other cobalt species were then compared. Data collectively revealed that 1 was stable during water oxidation; it did not release free Co 2+ ions and was not hydrolyzed to cobalt oxide or hydroxide, thereby confirming that 1 was the effective active species in water-oxidation catalysis. [ABSTRACT FROM AUTHOR]

Transition metal-based nitrogen-doped carbon materials have been proved to be a promising low-cost electrocatalyst for oxygen reduction reaction (ORR), which is a critical step in systems such as fuel batteries and zinc-air batteries. In this paper, transition metal (cobalt) N-doped carbon nanomaterials derived from metal-organic framework (MOFs) were synthesized by calcination of ZIF-67 precursors at high temperature (Co@NCNTs). Nitrogen atoms were introduced into the carbon matrix by capturing volatile CNx from dicyandiamide, and porous carbon nanotube structures with N-doped and uniformly dispersed active sites were obtained. The effects of different carbonization temperatures and molar ratio of Co/2-MI on the catalytic activity of materials for ORR reaction were studied. It was found that the Co@NCNTs prepared at 700 ℃ with the ratio of cobalt metal to dimethylimidazole of 1: 8 shows excellent ORR activity in both acidic and alkaline electrolytes. In alkaline conditions, the half-wave potential E 1/2 = 0.81 V, initial potential E onset = 0.89 V, and limiting current density even reaching 7.4 mA cm−2. And in acidic electrolytes, E 1/2 = 0.66 V, while the limiting current density is 6.4 mA cm−2, which is still better than that of Pt/C. Its excellent ORR performance is due to the synergistic effect of the porous carbon nanotube structure, N-doped carbon and Co-Nx active sites. Meanwhile, the optimum catalyst also shows better stability and methanol resistance than Pt/C in both acidic and alkaline electrolytes. [Display omitted] • N-doped porous carbon nanotubes coated Co material was used to enhance ORR activity in alkaline and acidic conditions. • Nanotube structure provides sufficient effective contact area and active sites. • Porous structure is conducive to mass diffusion and reduces electron transmission resistance. • N-doped carbon tube, Co-Nx and pyridine nitrogen jointly promote ORR activity. [ABSTRACT FROM AUTHOR]

• Magnetic material with mesoporous structure was successfully synthesized by direct carbonization of MIL-88B modified with l -alanine. • Magnetic mesoporous material as QuEChERS adsorbent can effectively remove the interfering substances in vegetables. • A rapid QuEChERS sample treatment method for the simultaneous determination of carbamate and neonicotinoid pesticides was established. • The recovery was 73.9–107.7%, RSD was ≤ 16.9%, show that the method is reliable. More and more attention has been paid to the improved QuEChERS (quick, easy, cheap, effective, rugged and safe) method in dealing complex sample matrices, especially for the study of QuEChERS adsorbents. In this study, a magnetic mesoporous material, which was derived from MIL-88B modified by l -alanine, was synthesized as modified QuEChERS adsorbents for the simultaneous determination of multiple pesticides (Methomyl, Isoprocarb, Carbofuran, 3-Hydroxycarbofuran, Acetamiprid, Imidacloprid) in Chinese cabbage, celery, long bean and leek. The prepared magnetic adsorbents can effectively remove interfering substances from the sample, and the proposed modified QuEChERS method can reduce sample pretreatment time via an external magnetic field. To achieve the best performance of QuEChERS method, the clean-up time and amount of QuEChERS adsorbents were investigated. Under the optimized conditions, a simple, rapid and sensitive method for the determination of 6 pesticide residues in vegetables was established by coupling the modified QuEChERS to ultrahigh-performance liquid chromatography-tandem mass spectrometry. Excellent sensitivity (The limit of detection for the 6 pesticides ranged from 0.001 to 0.020 µg kg−1), satisfactory linearity (r2 ≥ 0.9952), good recovery (73.9–107.7%) and good precision (3.6–16.9% for intraday relative standard deviation, 0.5–15.0% for interday relative standard deviation) were obtained. Compared with traditional QuEChERS method, the proposed method is simple, cost-effective, and efficient, which indicates that the method can be used to detect carbamate and neonicotinoid pesticides in real samples and provide an excellent pretreatment technique for the detection of trace multi-analytes from complex substrates. [ABSTRACT FROM AUTHOR]

A novel complex Fe/FeN@N-C nano-electrocatalyst was constructed by adopting a strategy of competitive coordination of nitrogen sources (2-methylimidazole). The competitive coordination of 2-methylimidazole promoted the generation of FeN active sites and greatly improved its ORR electrocatalytic performance. • The electrocatalyst synthesized with MOF as precursor, even distribution of active sites of the electrocatalysts. • Adopt a strategy of competitive coordination to synthesize a novel complex Fe/FeN@N-C electrocatalyst. • 2-methylimidazole promoted the generation of FeN active sites. • 2-methylimidazole acts as both a competitive ligand and a nitrogen source. • Excellent electrocatalytic properties and long-term stability. The development of controllable doping strategies is essential to obtain highly active electrocatalytic materials. Transition metal atoms with corresponding nitrogen coordination have been widely proposed as active centers for electrocatalytic oxygen reduction (ORR) in metal@nitrogen-carbon (M@N-C) electrocatalysts. In this paper, an effective competitive coordination strategy and high-temperature calcination were used to construct a novel complex Fe/FeN@N-C electrocatalyst. The synthesized catalyst, Fe-MIL-101-2-MI, was using 2-methylimidazole as a nitrogen source and a competitive ligand, which affects the nucleation and growth of the crystal. The morphology of the Fe-MIL-101-2-MI is nanorod, which is conducive to electron transport. Moreover, the competitive coordination of 2-methylimidazole promoted the generation of FeN active sites and greatly improved its ORR electrocatalytic performance. A series of Fe/FeN@N-C-X-Ts electrocatalytic samples was synthesized by controlling the doping amount of 2-methylimidazole and different calcining temperatures. Fe/FeN@N-C-2-800 composites exhibit high levels of doped N, even-distribution of Fe nanoparticles, and abundant FeN active sites. It is noteworthy that the half-wave potential of Fe/FeN@N-C-2-800 in the electrocatalytic ORR reaction is 0.813 V (vs. RHE), the initial potential is 0.873 V (vs. RHE), and the limit current density impressively reached 6.04 mA/cm2. In comparison to commercial Pt/C, the synthesized catalyst showed superior electrocatalytic performance. [ABSTRACT FROM AUTHOR]