Science Advances
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2025
·Vol. 11
·期 9
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IF 12.5
Mengxue Huang,Xuya Zhu,Wenwen Shi,Qianqian Qin,Jie Yang,Shanshan Liu,Lifang Chen,Ruimin Ding,Lin Gan,Xi Yin
Nitrogen-coordinated metal sites (MNx) in metal- and nitrogen-codoped carbon (M-N-C) catalysts offer promising electrocatalytic activity, but selective synthetic design of MNx sites with specific coordination environments remains challenging. Here, we manipulate the formation statistics of MNx sites by using sacrifice alkali metals (AM = Li, Na, and K) to form metal vacancy-Nx carbon (AM-MVNx-C) templates, which are used to direct the solution-phase formation of CoN4 sites in Co-N-C catalysts. We build a probability weight function based on the embedding energy of M in MNx sites as the descriptor for MNx formation statistics, and we predict that the alkali metals are prone to induce the formation of MVN4 sites. By coordinating Co2+ ions with AM-MVNx-C templates, we synthesize Co-N-C with CoN4 sites, demonstrating remarkable oxygen reduction activity in anion exchange membrane fuel cells. These results highlight the statistical thermodynamics of MNx formation and open up the possibility for the rational design of complex M-N-C electrocatalysts with well-defined MNx sites.
研究领域:
材料科学
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电化学
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产品关联
DOI
PubMed
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2020
·Vol. 129
·期 2
·865-881
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IF 1.52
Liu Minjie,Zhang Hao,Wang Junyan,Zhao Guoming,Liu Di
A Co–N–C catalyst was fabricated via pyrolysis–reduction process. Dehydrogenation/hydrogenation and base catalysis performances of the Co–N–C catalyst were investigated by using the reductive coupling of nitroarenes with alcohols and aldol condensation as probe reactions. Various characterizations were performed to explore effects of reduction and pyrolysis temperature on the structure/composition and basicity of the Co–N–C catalyst, and the relationship between structure-dehydrogenation/hydrogenation and base catalysis performance was discussed accordingly. Two different structures of Co–N–C catalyst (Co–N–C/C 3 N 4 and Co–N–C/CNT) were obtained in different pyrolysis temperature. Co–N–C-600 with C 3 N 4 exhibits very weak catalytic performance owe to its poor pore system and active phase. Dehydrogenation/hydrogenation behaviors of Co–N–C/CNT depend on the amount of Co–N, graphitic N in Co–N–C, while the basicity of Co–N–C is closely related to the content of N species, particularly pyrrolic N and pyridinic N. The appropriate pyrolysis temperature benefits the formation of active species, developed pore organization and strong basicity. And, the H 2 reduction improve dehydrogenation/hydrogenation activity of Co–N–C/CNT because reduction can destroy carbon coating layers to expose more Co–N species and promote the transformation of N species to graphitic N. Meanwhile, H 2 reduction increases the contents of graphitic N and reduces the content of pyrrolic N and pyridinic N, thus weakening catalyst basicity and consequently reducing base catalytic activity of Co–N–C/CNT.
研究领域:
化学
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催化材料科学
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2022
·
IF 6.371
Dege Xili,Qian Zhou,Lijuan Zhang
Non-precious metal nitrogen-carbon composites (M-N-C) derived from ZIFs are an excellent non-precious metal catalyst for use in energy conversion and storage devices such as fuel cells and metal-air batteries. Herein ZIF-67 precursor with good dispersion, perfect crystal structure and size of below 270 nm was synthesized by consuming low amount of 2-methylimidazole ligand using a mixture of ethanol (EA) and methanol (MT) as the reaction medium. Compared with the traditional method of reducing the size of ZIF-67 by increasing the amount of ligands in methanol, this method avoids the waste of raw materials and saves the cost. The Co-N-C-MT/EA catalysts derived from ZIF-67 exhibits good ORR activity in alkaline media (0.1 M KOH) with a half-wave potential of 0.81 V vs RHE. After 5000 cycles, the initial potential and half-wave potential basically remain no change, showing excellent long-term stability. And remarkable methanol resistance is also displayed comparing with commercial Pt/C. The present experimental result shows that the improved synthesis method of ZIF-67 precursors has far-reaching implications for the field of catalyst research.
研究领域:
材料科学
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催化化学
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能源转换与存储
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DOI
高影响因子
FUEL
·
2025
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IF 7.5
Wei Wen,Chunying Wang,Xudong Chen,Jingyi Wang,Yaobin Li,Fei Wang,Wenpo Shan,Ping Ning,Kai Li
Two-dimensional materials have garnered significant attention in the field of catalysis due to their high electron transfer efficiency. In this study, a quasi-two-dimensional carbon–nitrogen doped cobalt-based catalyst (Co-N-C (F)) was synthesized for the investigation of formaldehyde (HCHO) oxidation at room temperature. The electronic coordination structure of the catalyst was modified by varying the calcination temperature, resulting in the formation of Co-N 4 sites that enhance the degradation of the intermediate formate. Additionally, the quasi-2D structure formed during high-temperature pyrolysis retains characteristics of the ZIF 3D material, with a high specific surface area and a porous aggregation structure, which further enhances the exposure of active centers and diffusion of the feed gas. Characterization results showed that the number of Co-N 4 sites on the catalysts increases with the rise in pyrolysis temperature, with the Co-N-C (F)-1000 catalyst exhibiting the highest concentration of Co-N 4 sites. Activity test results indicated that the Co-N-C (F)-1000 catalyst achieved a 100 % HCHO removal rate at 25 °C, with WHSV 200,000 mL/(g·h). In contrast, the activity of the Co-N-C (F)-1100 catalyst decreased, which could be attributed to the aggregation of Co particles at excessively high temperatures. The HCHO oxidation mechanism of the Co-N-C (F) catalysts was investigated using in situ diffuse reflectance infrared spectroscopy ( in situ DRIFTS), and the reaction was found to follow the sequence HCHO → HCOO − → CO 2 + H 2 O, with formate degradation as a rate-limiting step.
研究领域:
催化材料
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环境科学
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化学工程
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DOI
高影响因子
CATALYSIS TODAY
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2019
·
IF 4.888
Mantang Chen,Nan Wang,Lihua Zhu
Single-atom catalysts with a maximum atomic utilization are promising in wastewater treatment. Herein, a single-atom dispersed Co-N-C catalyst was prepared by a calcination-acid treatment method. The obtained Co-N-C was confirmed to possess excellent performances of both adsorption and catalytic ability of activating peroxymonosulfate (PMS). It was found that the adsorption performance was related to the surface area and pore volume and the removal of bisphenol A (BPA) was determined by the defect density of the catalyst. It was observed that a calcination temperature of 900 °C yielded the best Co-N-C catalyst named Co-N-C-900. All the added BPA (80 mg L −1 ) was completely degraded in 3 min by using 0.5 g L −1 Co-N-C-900 and 0.3 g L −1 PMS with a degradation rate constant ( k ) of as high as 2.81 min −1 . In this single-atom catalytic system, the main reactive species were confirmed to be singlet oxygen. A mechanism study suggested that the fast and efficient degradation of BPA was attributed to the synergistic effect between fast adsorption of mesoporous carbon and efficient catalysis of single-atom Co-N x complex.
研究领域:
环境科学
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材料科学
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化学工程
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产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2021
·Vol. 33
·期 10
·105601
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IF 3.874
Li Lin,Xing Du,Junjie Wang,Hui Chen,Xuan He,Wei Fang,Yang Li,Zhen Chen,Lei Zhao
Two-dimensional (2D) cobalt zeolitic imidazolate frameworks (ZIF-67) have attracted significant research interests to synthesize cobalt and nitrogen co-doped carbon-based (Co–N–C) catalyst for oxygen reduction reaction (ORR). However, most of the current synthetic approaches of 2D ZIF-67 are energy-intensive, environmentally hazardous and low-yield. Herein, a feasible and efficient 'morphology-retaining method via a high-pressure vapor-solid reaction' are reported to synthesize 2D ZIF-67 nanosheets by using 2D cobalt carbonate hydroxide template. In the strategy, the high-pressure vapor caused by sublimation of 2-Melm and the pores formed from effusion of CO2 during transformation ensure the complete transformation from 2D template to 2D ZIF-67. The corresponding 2D Co–N–C catalyst exhibits comparable ORR electrocatalytic activity and better stability than Pt/C in alkaline media. The present method is expected to offer a feasible and universal way to efficiently synthesize 2D M–N–C catalysts.
研究领域:
材料科学
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电化学
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催化
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产品关联
DOI
PubMed
高影响因子
Environmental Science-Nano
·
2024
·Vol. 11
·期 5
·2010-2020
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IF 5.8
Yanqing Cong,Lingjie Ye,Qiuang Zheng,Yudi Wang,Yifan Shao,Xuhua Ren,Shi-Wen Lv
Water pollution has always been an issue of significant human concern, and the development of effective wastewater treatment processes is important. Herein, three Co–N/C-based catalysts with different types of nitrogen were fabricated and employed to activate peroxymonosulfate (PMS) for tetracycline (TC) degradation. Due to the existence of a spatial confinement effect, all the Co–N/C-based catalysts showed excellent catalytic activities, and the removal efficiencies of TC were over 90% within 10 min. Notably, current results indicate that the Co–N/C-based catalyst rich in pyridinic N provides electrons to break the peroxy bonds of PMS for generating SO4˙−, while the Co–N/C-based catalyst containing more pyrrolic N acquires electrons from PMS to produce SO5˙−, which is further converted into 1O2. Moreover, the Co–N/C-based catalyst rich in graphitic N displayed good performance in electron transfer and can mediate the direct electron transfer process between TC and PMS. More interestingly, radical-induced oxidation exhibited a high TOC removal efficiency, but the corresponding anti-interference ability was weak. 1O2-induced oxidation and direct electron transfer process had a high removal efficiency for TC and good anti-interference ability, but the mineralization efficiency was relatively low. In short, the current work will provide a valuable reference for future research.
研究领域:
环境科学
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催化化学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Rui Wang,Hongcen Yang,Niandi Lu,Shulai Lei,Dali Jia,Zhixia Wang,Zhenhua Liu,Xiaogang Wu,Hanzhen Zheng,Salamat Ali,Fei Ma,Shanglong Peng
Developing highly active and robust non-noble metal bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of dominant significance for global applications in rechargeable Metal-air Batteries. Fine-tuning the exposed active sites is a competent way to improve their performance. Herein, the NaCl template-assisted strategy for rationally designing a three-dimensional cellular structured nitrogen-doped carbon matrix integrated with nano-scaled Co species has been developed. The resulting electrocatalyst (3D Co/N-C) exhibits a positive half-wave potential of 0.84 V (vs RHE) in ORR, and a low potential of 1.56 V (vs RHE) at 10 mA cm −2 during OER process. Moreover, 3D Co/N-C based Zn-air Batteries (ZABs) exhibit excellent battery performance, especially remarkable power density. The poisoning experiments and DFT calculations identify active sites as pyridinic N and Co during ORR and OER processes, respectively. This work provides a general and easy-to-perform tactic to design bifunctional catalysts, thus helps precisely modulate effective components for ZABs.
研究领域:
电化学
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材料科学
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能源存储
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产品关联
DOI
高影响因子
Nature Communications
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2020
·Vol. 11
·期 1
·1-10
·
IF 12.121
Wang Xiuyun,Peng Xuanbei,Chen Wei,Liu Guangyong,Zheng Anmin,Zheng Lirong,Ni Jun,Au Chak-tong,Jiang Lilong
The industrial synthesis of ammonia (NH 3 ) using iron-based Haber-Bosch catalyst requires harsh reaction conditions. Developing advanced catalysts that perform well at mild conditions (<400 °C, <2 MPa) for industrial application is a long-term goal. Here we report a Co-N-C catalyst with high NH 3 synthesis rate that simultaneously exhibits dynamic and steady-state active sites. Our studies demonstrate that the atomically dispersed cobalt weakly coordinated with pyridine N reacts with surface H 2 to produce NH 3 via a chemical looping pathway. Pyrrolic N serves as an anchor to stabilize the single cobalt atom in the form of Co 1 -N 3.5 that facilitates N 2 adsorption and step-by-step hydrogenation of N 2 to *HNNH, *NH-NH 3 and *NH 2 -NH 4 . Finally, NH 3 is facilely generated via the breaking of the *NH 2 -NH 4 bond. With the co-existence of dynamic and steady-state single atom active sites, the Co-N-C catalyst circumvents the bottleneck of N 2 dissociation, making the synthesis of NH 3 at mild conditions possible.
研究领域:
催化
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化学工程
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材料科学
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产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2020
·
IF 3.687
Wei Wu,Wei Zhang,Yu Long,Jiaheng Qin,Jiantai Ma
In this work, by the simple pyrolysis of Fe 2+ , Co 2+ or Ni 2+ and 1,10-phenanthroline (Phen) complexes under the presence of activated carbon and dicyandiamide in nitrogen atmosphere, different nonprecious transition metal-based species that well confined in nitrogen doped carbon (M-N-C, M = Fe, Co or Ni) were prepared. The Fe-N-C showed the best catalytic performance for the transfer hydrogenation of halogenated nitrobenzenes. More importantly, through the catalytic results comparison of the three catalysts estimated by gas chromatography-mass spectrometer, two speculations might be presented for the reaction pathway depending on the catalyst used. The transfer hydrogenation reaction route over Fe-N-C might follow the indirect way like the Co-N-C and Ni-N-C. Another assumption was the Fe-N-C might go through the direct pathway in contrast to the Co-N-C and Ni-N-C which resulted in formation of azoxybenzene and azobenzene intermediates before complete conversion to aniline. Those differences were found to be correlated with the different valence states and active metal components in different catalysts. In addition, the optimal Fe-N-C could be efficiently recovered by using an applied magnetic field and reused without significant decrease of activity. Therefor the catalyst may possess important potential for the industrial application in the selective hydrogenation of halogenated nitrobenzenes.
研究领域:
催化化学
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材料科学
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环境化学
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产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2021
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IF 10.588
Huiwang Dai,Wenjun Zhou,Wei Wang,Zhiqi Liu
In this study, three Co/N-C catalysts were prepared by pyrolysis of bimetallic zeolitic imidazole frameworks with different Co/Zn ratio, and the critical active Co species in peroxymonosulfate (PMS) activation was investigated. The three catalysts had distinct cobalt species but similar N configuration and graphitization degree. The Co species were distributed as single atoms (Co SAs) at a Co/Zn molar ratio of 1:8, while Co nanoclusters (Co NCs) and Co nanoparticles (NPs) would be formed with further increase in Co content. The degradation efficiency of BPA did not show correlation with the increasing of Co content in catalyst. Based on the catalytic performance comparison and reactive species detection, Co SAs was identified as active sites, which could interact with PMS to generate 1 O 2 via path of PMS→HOO*→O*→ 1 O 2 . However, the role of NCs and NPs in directly activating PMS was negligible. In addition, the increase of Co content in Co/N-C catalyst would result in mass cobalt leaching, which enhanced the BPA degradation via homogeneous catalytic reactions with Co IV as reactive species. It is an effective way to design the Co/N-C catalyst with high catalytic activity and stability via regulating the formation of Co SAs.
研究领域:
环境化学
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催化
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材料科学
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产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2018
·
IF 0
Shanshan Jie,Congqiang Yang,Yuan Chen,Zhigang Liu
The highly dispersed active sites are desirable to optimize the atom efficiency. In this study, a series of novel cobalt grafted in N-doped carbon (Co-N-C) catalysts for selective oxidation of ethylbenzene are synthesized by heating a solution of cobalt porphyrin and peptides in ionic liquids, which are also characterized by techniques such as FT-IR, XRD, SEM-EDX, HR-TEM, and XPS. The results show that the as-prepared catalysts have an attractive catalytic performance, namely, 40% of ethylbenzene conversion and 75% of selectivity to acetophenone. Especially, the activity and selectivity of the as-prepared catalysts remain almost similar even after the 10th run. Moreover, the modified-complexometry method is verified to improve the dispersion of metal active sites. The remarkable catalytic performance of the as-prepared catalysts is attributed to the highly dispersed active sites and strong interactions between Co and N species in Co-N x moieties.
研究领域:
催化
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材料科学
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化学工程
·
分析化学
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产品关联
DOI
危险品化学品经营许可证（带存储）