Nano Research
·
2021
·Vol. 15
·期 1
·519-527
·
IF 8.897
Zhou Dan,Zhang Leilei,Liu Xiaoyan,Qi Haifeng,Liu Qinggang,Yang Ji,Su Yang,Ma Jingyuan,Yin Jianzhong,Wang Aiqin
Fine-tuning of the coordination environment of single-atom catalysts (SACs) is effective to optimize their catalytic performances, yet it remains challenging due to the vulnerability of SACs. Herein, we report a new approach to engineering the coordination environment of M-N-C (M = Fe, Co, and Ni) SACs by using glutamic acid as the N/C source and pyrolysis atmosphere as a regulator. Compared with that in N 2 , NH 3 was able to promote the doping of N at T < 700 °C yet etch the N-species at higher temperatures, by which the M-N coordination number (CN) and the electronic structure were delicately tuned. It was found that the electron density of Ni single atoms increased with the decrease of Ni-N CN. As a consequence, the capability of Ni-N-C to dissociate H 2 was greatly enhanced and a higher catalytic activity in chemoselective hydrogenation of functionalized nitroarenes was achieved. Moreover, this modulation method could be applied to other transition metals including Fe and Co. In particular, the as-synthesized Co-N-C SAC afforded a turnover frequency of 152.3 h −1 with 99% selectivity to 3-vinylaniline in the hydrogenation of 3-nitrostyrene, which was the highest ever reported thus far and was at least one order of magnitude more active than state-of-the-art noble-metal-free M-N-C catalysts, demonstrating the great potential of engineering the coordination environment of SACs.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2023
·
IF 22.1
Rui Sui,Jing Chai,Xuerui Liu,Jiajing Pei,Xuejiang Zhang,Xingdong Wang,Yu Wang,Juncai Dong,Wei Zhu,Wenxing Chen,Liang Zhang,Zhongbin Zhuang
The metal-nitrogen-carbon (M-N-C) type oxygen reduction reaction (ORR) catalysts are promising for hydroxide exchange membrane fuel cells, but catalysts with further improved performance are challenging. Here, we report the efficient improvement of the ORR activity of M-N-C catalysts by employing highly polarizable metal cation Ag + . Ag, Fe single atomic sites embedded in concave nitrogen doped carbon (Ag 1 Fe 1 /CNC) is successfully synthesized and shows high performance towards ORR, indicating by both the ultra-high half-wave potential of 0.917 V and membrane electrolyte assembly performance of peak power density up to 1.26 W cm −2 . The binding energy of the ORR intermediates on the highly polarizable Ag site in Ag 1 Fe 1 /CNC was significantly tuned by the adjacent Fe site by more than 0.2 eV, and thus leading to a low theoretical ORR overpotential of only 0.398 V. The employment of the highly polarizable metal cation brings a novel and efficient approach to construct highly active catalysts.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Mingjun Xu,Zhao Jin,Meiling Xiao,Changpeng Liu,Wei Xing
The single-atom dispersed active sites and the thicker catalytic layer of metal-nitrogen-carbon (M-N-C) electrocatalysts based membrane electrode assembly (MEA) exhibit notable distinctions from Pt-based MEA, necessitating targeted optimization. This study systematically investigates the influence of compression on both structure and performance of the M-N-C electrocatalysts based MEA. Four compression ratios, ranging from 11.5% to 39.3%, were examined across diverse operational conditions. The variations in impedance across different electrochemical regions are observed, resulting from the superposition of distinct impedance components. It is found that the insufficient compression leads to higher porosity and the formation of cracks between catalytic layer and membrane, adversely impacting internal resistance and proton transport. Increasing compression first acts the catalytic layer, and then gradually acts on the interface, membrane and gas diffusion layer, thereby reducing internal resistance, charge transfer resistances, albeit at the expense of heightened mass transfer resistance. Among these factors, the influence of internal resistance affects significance to total performance. Furthermore, compression influenced mass transfer differently in various layers. For the catalyst layer, the effect was uniform and sustained, while for the gas diffusion layer, it initially remained constant and then experienced a sudden deterioration over a certain extent. Optimal MEA performance is achieved when the compression ratio attains 40 %, which 2.1 times higher than the low compression MEA. This finding emphasizes the necessity for higher compression on M-N-C electrocatalysts based MEA compared to Pt-based MEA.
研究领域:
能源科学
·
材料科学
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DOI
高影响因子
ACS Applied Nano Materials
·
2023
·
IF 5.9
Xu Hu,Ling-Yu Dong,Yong-Qi Ren,Wen-Cui Li,Martin Oschatz,Guang-Ping Hao,An-Hui Lu
The efficient utilization of active centers for the emerging class of metal (M) and nitrogen (N) co-doped carbon (M–N–C) catalysts remains a research hotspot for electrochemical synthesis such as the reduction reactions of CO2, O2, N2, or functional groups in organic molecules. However, keeping sufficient accessibility to these active centers upon thermal treatment at high temperatures can be challenging due to possible nanopore blocking issues. To tackle this limitation, this work presents a precise surface modulation approach based on a kind of porous carbon support with an ultrapolar surface, over which the unusual enhancement of nanopore accessibility and metal utilization is achieved. The strategy is well applicable to transition metals, precious metals, and rare earth metals. Experimental evidence revealed that the ultrapolar pore walls can be spontaneously wetted by hydrated metal ions. The unprecedented wettability ensured a unique metal-support interaction, which not only warrants the anchoring metal species in a dispersed manner but also induces the development of transport nanopores by dynamical etching of the polar carbon walls during thermal treatment. By this way, this strategy addresses the trade-off issue between metal utilization efficiency and accessibility to the active centers for the M–N–C type catalysts.
研究领域:
材料科学
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电化学
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催化反应
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry Letters
·
2025
·
IF 4.6
Weidong Liang,Yong Zhang,Dongniu Wang,Jianzhao Peng,Jinshuo Zou,Huiqi Li,Zhongxin Song,Manlin Tan,Jun Yu,Lei Zhang
Optimizing the electronic structures of metal sites is desirable for high intrinsic activity. Incorporated metal atoms in a carbon substrate can establish strong electronic interaction with loaded metal oxides. However, this structure may be unstable in a harsh oxygen evolution reaction (OER) environment. Herein, we take the NiSAFe sample of Ni–N–C supported Fe2O3 nanoparticles (NPs) as an example. Both in situ and ex situ characterizations show that the OER activation process facilitates the transformation of Ni single atoms into atomically dispersed NiOOH active species while retaining Fe2O3 NPs. Accordingly, abundant structural defects are formed in the carbon support, enhancing electron transfer and upshifting the d-band center of the NiFe catalyst. As a result, the catalyst exhibits accelerated OER kinetics and optimized adsorption energies for reaction intermediates, delivering outstanding intrinsic activity. A low overpotential of 230 mV at 10 mA cm–2 and a turnover frequency (TOF) more than 9 times higher than that of commercial RuO2 are achieved.
研究领域:
电催化
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材料科学
·
能量转换
·
纳米材料
·
表面化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2026
·
IF 4.9
Yun-Rui Lv,Jia-Hui Zhang,Kun Fang,Duo-Duo Liu,Nan Li,Li-Ping Si,Hai-Yang Liu
Achieving low-cost and scalable fabrication of oxygen reduction reaction (ORR) catalysts remains one of the central challenges for the commercialization of high-performance energy conversion devices. In this work, Livistona chinensis leaves (LCL) are used as the sustainable bioorganic frame (BOF) precursor for constructing the carbon material LCLC. After doping transition metal (Fe, Co, Mn) 1, 10, 15-tris(pentafluorophenyl)corrole (TPFC) complexes and followed by pyrolysis, the carbon based ORR electrocatalysts MTPFC/LCLC bearing the metal-nitrogen-carbon (M-N-C) active site were prepared. Of all prepared MTPFC/LCLC, the iron corrole doped carbon material FeTPFC/LCLC exhibited the best electrocatalytic ORR activity, featuring a half-wave potential ( E 1/2 ) of 0.877 V (Vs the reversible hydrogen electrode, RHE). The constructed zinc-air battery (ZAB) by using FeTPFC/LCLC cathode achieved an open-circuit voltage of 1.48 V and a specific capacity of 809.9 mAh g -1 (based on consumed Zn), both surpassing the commercial Pt/C catalyst. Our work proved the tremendous potential of Bioorganic frame derived carbon and metal corrolates for practical ORR catalysts.
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DOI
高影响因子
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
·
2023
·Vol. 120
·期 14
·e2219043120
·
IF 11.1
Huan Wang,Youzeng Li,Maoyu Wang,Shan Chen,Meng Yao,Jialei Chen,Xuelong Liao,Yiwen Zhang,Xuan Lu,Edward Matios,Jianmin Luo,Wei Zhang,Zhenxing Feng,Jichen Dong,Yunqi Liu,Weiyang Li
Despite the various strategies for achieving metal–nitrogen–carbon (M–N–C) single-atom catalysts (SACs) with different microenvironments for electrochemical carbon dioxide reduction reaction (CO2RR), the synthesis–structure–performance correlation remains elusive due to the lack of well-controlled synthetic approaches. Here, we employed Ni nanoparticles as starting materials for the direct synthesis of nickel (Ni) SACs in one spot through harvesting the interaction between metallic Ni and N atoms in the precursor during the chemical vapor deposition growth of hierarchical N-doped graphene fibers. By combining with first-principle calculations, we found that the Ni-N configuration is closely correlated to the N contents in the precursor, in which the acetonitrile with a high N/C ratio favors the formation of Ni-N3, while the pyridine with a low N/C ratio is more likely to promote the evolution of Ni-N2. Moreover, we revealed that the presence of N favors the formation of H-terminated edge of sp2 carbon and consequently leads to the formation of graphene fibers consisting of vertically stacked graphene flakes, instead of the traditional growth of carbon nanotubes on Ni nanoparticles. With a high capability in balancing the *COOH formation and *CO desorption, the as-prepared hierarchical N-doped graphene nanofibers with Ni-N3 sites exhibit a superior CO2RR performance compared to that with Ni-N2 and Ni-N4 ones.
研究领域:
材料科学
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电化学
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催化
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）