JOURNAL OF POWER SOURCES
·
2014
·
IF 5.211
Dong Liu,Xueping Zhang,Tianyan You
Nitrogen-doped carbon nanofibers (NCNFs) are prepared by the thermal treatment of carbon nanofibers (CNFs) using urea as nitrogen source. Scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy have been employed to characterize the morphology and composition of CNFs and NCNFs. Compared with CNFs, NCNFs display thinner diameter, rougher surface and higher content of pyrrolic-N. As a metal-free catalyst for ORR , NCNFs exhibit comparable catalytic activity , significantly enhanced long-time stability and selectivity in comparison with commercial available Pt/C catalyst. Importantly, the self-supported NCNFs films could be conveniently utilized for electrode modification which is attractive in fuel cells. This work offers a promising metal-free catalyst as an alternative for Pt/C catalyst.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Bao Men,Yanzhi Sun,Mujie Li,Chaoqun Hu,Man Zhang,Linan Wang,Yang Tang,Yongmei Chen,Pingyu Wan,Junqing Pan
Hierarchical nitrogen-doped porous graphene/carbon (NPGC) composites were fabricated by a simple and nontemplate method. The morphology characterizations demonstrate that reduced graphene oxide was successfully coated by the carbon derived from glucose, and a well-organized and interpenetrated hierarchical porous structure of NPGC was formed after pyrolysis at 950 °C. Notably, the prepared material, denoted as NPGC-950, has superlarge specific surface area (1510.83 m2 g–1) and relatively high content percentage of pyridinic and graphitic nitrogen. As an efficient metal-free electrocatalyst, NPGC-950 exhibits a high onset potential (0.91 V vs RHE) and a nearly four-electron pathway for oxygen reduction reaction in alkaline solution as well as stronger methanol tolerance and better long-term durability than commercial Pt/C. In view of these excellent features, the obtained hierarchical N-doped metal-free porous carbon material is a promising catalyst for oxygen reduction reaction and could be widely applied in industry.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2021
·Vol. 38
·期 1
·167-172
·
IF 1.307
Yu Xiaoming,Ma Yunchao,Li Cuiyan,Guan Xinyu,Fang Qianrong,Qiu Shilun
O xygen reduction reaction(ORR) is a significant reaction for energy conversion systems(such as fuel cells, metal-air batteries, etc.). It is an urgent need to develop cheap, durable and highly-active catalysts for efficient ORR. Hence, we report a metal-free nitrogen and sulfur co-doped porphyrin-based covalent organic framework(COF) as a high-efficiency ORR catalyst[the onset potential( E o ) is 0.79 V and the half-wave potential( E 1/2 ) is 0.70 V]. The double doping of N and S atoms causes uneven charge distribution around carbon atoms, which can act as catalytic active centers, improving ORR activity. Compared with single-atom doping, double atoms doping exhibits a higher activity due to the synergistic effect between different elements. These results demonstrate that reasonable design of stable metal-free COFs with a high electrochemical activity can promote their wide applications.
研究领域:
材料科学
·
能源化学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Qian Peng,Ying Dai,Kun Liu,Xuekun Tang,Muyang Zhou,Yingjie Zhang,Jiajie Xing
A metal-free peroxymonosulfate catalyst based on chrysotile and graphite carbon nitride (g-C 3 N 4 ) was synthesized for the first time. The abundant hydroxyl groups of chrysotile can react with amine groups of urea-derived intermediates and accelerate formation of double nitrogen defects (N-vacancy and cyano group) in g-C 3 N 4 , which can drastically improve the activation efficiency of PMS. The introdution of chrysotile can greatly increase the reaction time of hydroxyl and amine groups, and promote the generation of double nitrogen defects. This catalyst displayed superior catalytic performance for rhodamine B (RhB) degradation than bare chrysotile and g-C 3 N 4 . Moverover, this catalyst also has good cycle performance, structural stability and universal applicability, which provides an idea for the comprehensive utilization of asbestos tailings and environmental remediation.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2025
·
IF 17.7
Shuhao Wei,Ye Chen,Yiyang Qiu,Wei Kong,Di Lin,Jiarong Li,Guojun Lan,Yi Jia,Xiucheng Sun,Zaizhe Cheng,Jian Liu,P. Hu,Ying Li
Metal-free carbon catalysts have garnered significant attention since their inception. Despite substantial advancements, including widely adopted strategies such as heteroatom doping and defect engineering, their catalytic performance remains inferior to that of metal-based catalysts. In this study, we have predicted and demonstrated that the curvature of carbon plays a pivotal role in the adsorption of acetylene and the overall catalytic performance. First-principles calculations suggest that a tip-enhanced local electric field at the defect site on the curved carbon catalyst enhances the reaction kinetics for acetylene hydrochlorination. The experimental results highlight the structural advantages of the curved defect site, revealing that high-curvature defective carbon (HCDC) demonstrates an adsorption capacity for acetylene that is almost two orders of magnitude higher than that of defective carbon. Notably, HCDC achieves an acetylene conversion of up to 90% at 220 °C under a gas hourly space velocity of 300 h –1 , significantly surpassing the performance of the benchmark 0.25% Au/AC catalyst. This proof-of-concept study reveals the fundamental mechanisms driving the superior performance of carbon catalysts with curved nanostructures and presents a straightforward, environmentally friendly method for large-scale production of carbon materials with precisely controlled nanostructures. It highlights the potential for commercializing metal-free carbon catalysts in acetylene hydrochlorination and related heterogenous catalytic reactions.
研究领域:
材料科学
·
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Science
·
2022
·Vol. 9
·期 17
·2200518
·
IF 17.521
Juan Meng,Zhihan Tong,Haixin Sun,Yongzhuang Liu,Suqing Zeng,Jianing Xu,Qinqin Xia,Qingjiang Pan,Shuo Dou,Haipeng Yu
An in-depth understanding of the electronic structures of catalytically active centers and their surrounding vicinity is key to clarifying the structure–activity relationship, and thus enabling the design and development of novel metal-free carbon-based materials with desired catalytic performance. In this study, boron atoms are introduced into phosphorus-doped nanoporous carbon via an efficient strategy, so that the resulting material delivers better catalytic performance. The doped B atoms alter the electronic structures of active sites and cause the adjacent C atoms to act as additional active sites that catalyze the reaction. The B/P co-doped nanoporous carbon shows remarkable catalytic performance for benzyl alcohol oxidation, achieving high yield (over 91% within 2 h) and selectivity (95%), as well as low activation energy (32.2 kJ mol −1 ). Moreover, both the conversion and selectivity remain above 90% after five reaction cycles. Density functional theory calculations indicate that the introduction of B to P-doped nanoporous carbon significantly increases the electron density at the Fermi level and that the oxidation of benzyl alcohol occurs via a different reaction pathway with a very low energy barrier. These findings provide important insights into the relationship between catalytic performance and electronic structure for the design of dual-doped metal-free carbon catalysts.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
GREEN CHEMISTRY
·
2016
·Vol. 18
·期 15
·4254-4262
·
IF 8.506
Fan Yang,Cheng Chi,Chunxia Wang,Ying Wang,Yongfeng Li
Four kinds of nitrogen-doped graphene (NG) as metal-free catalysts are synthesized by a one-step hydrothermal reaction and thermal treatment using graphene oxide and urea as precursors. It is found that the reduction of nitroarenes can be catalyzed by using a low NG loading and a small amount of NaBH4 in water with high yield. The type of nitrogen species in NG has an important effect on the reduction reaction. The NG catalyst containing the most graphite N shows the highest catalytic activity during reduction of nitroarenes, which demonstrates that the graphite N of NG plays a key role in impelling this reaction. The reaction mechanism is proven by GC-MS experiments, and DFT calculations reveal the reasons for the graphite N showing better catalytic activity. It is worth noting that no dehalogenation phenomenon occurs during the reduction process for halogen-substituted nitroarenes in contrast to conventional metal catalysts. In addition, the NG catalyst can be simply recycled and efficiently used for eight consecutive runs with no significant decrease in activity.
研究领域:
材料科学
·
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Bin Chang,Lili Li,Dong Shi,Hehe Jiang,Zizheng Ai,Shouzhi Wang,Yongliang Shao,Jianxing Shen,Yongzhong Wu,Yanlu Li,Xiaopeng Hao
From a thermodynamic point of view, electrocatalytic nitrogen reduction reaction (NRR) is possible for the carbon-based metal-free catalysts, which are gradually becoming a class of potential alternatives to metal-based catalysts. However, the clarification of true active sites and corresponding exact catalytic mechanism of metal-free catalysts is urgently required. Taking full advantage of boron “Lewis acid”, a series of boron carbonitride (BCN) materials were designed and synthesized and the “Lewis acid catalysis” sites were tuned easily by adjusting the relative contents of boron and nitrogen atoms. Boron-enriched BCN exhibited outstanding NRR performance with an ammonia yield of −8.39 μg h −1. cm −2 cat. (−41.9 μg h −1. mg −1 cat. ) and Faradaic efficiency of −9.87 %, together with excellent stability. Density functional theory calculations indicate that the boron sites of BCN enable the low energy barrier of the NRR rate-determining steps and the spontaneity of nitrogen adsorption. Our philosophy opens a new possible avenue to explore high-performance metal-free materials for nitrogen activation.
研究领域:
材料科学
·
电化学
·
理论计算
✓ 已验证
DOI
高影响因子
ENERGY
·
2018
·
IF 4.968
Wenjing Yuan,Anjian Xie,Ping Chen,Fangzhi Huang,Shikuo Li,Yuhua Shen
Finding an effective approach to prepare low-cost metal-free catalysts with excellent catalytic performance for the oxygen reduction reaction (ORR) is a crucial challenge for the commercialization of fuel cells. Herein, a novel and effective combustion approach was designed in order to construct the three-dimensional porous carbon foam and followed by heat treatment in an NH 3 atmosphere. In the combustion process , sucrose was used as the carbon source to produce the carbon framework, sodium bicarbonate as the pore-foaming agent to form the porous structure . This synthetic route is novel, cost-effective and without using any templates, expensive equipment as well as highly toxic chemical reagents. Compared with the control samples, the typical product exhibits the excellent catalytic activity in terms of not only a positive onset potential and high current density , but also low H 2 O 2 yield and approximate four-electron reaction pathway in alkaline media . The reason may be attributed to the synergistic effect of the three-dimensional porous structure, high BET surface area (up to 1216 m 2 g −1 ) and effective nitrogen-doping of the product. In addition, the novel method is of great importance, which may guide future efforts for the development of other porous carbon-based materials for applications in multi-fields.
研究领域:
材料科学
·
电化学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Xiaoyu Tian,Minghua Zhou,Chaolin Tan,Ming Li,Liang Liang,Kerui Li,Pei Su
N-doped carbon aerogel (CA) was prepared by one-pot template-free synthesis and chemically activated with potassium hydroxide (KOH). KOH activation highlighted the structural superiority with increased BET surface area and hierarchically porous structure (especially micropores), and also significantly influenced active nitrogen species and oxygen functional groups (C O C and COOH) content. With KOH increasing, pyridinic N content increased, while pyrrolic N content decreased. Oxygen reduction reaction (ORR) activity showed a positive linear correlation with pyridinic N content but decreased with pyrrolic N content increasing. C O C and COOH content increased after activation, and then decreased with KOH increasing. The reduced C O C and COOH content of CA-KOH guaranteed a lower H 2 O 2 yield for higher microbial fuel cell (MFC) efficiency. CA-10KOH (mass ratio of KOH to CA was 10) exhibited outstanding performance with the highest maximum power density (967 ± 34 mW m −2 ), which was 37.4%, 55.2% and 283.7% higher than platinum (Pt/C), activated carbon (BET surface area of 2276 m 2 g −1 ) and CA. The outstanding performance of CA-10KOH was attributed to the conjunct effect of superior BET surface area (1827 m 2 g −1 ), increased micropores, the highest pyridinic N (0.26 at.%), the lowest pyrrolic N content and reduced C O C and COOH content. Overall, KOH activated CA is a promising metal-free cathode catalyst for high performance in MFCs.
研究领域:
环境科学
·
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2015
·Vol. 7
·期 28
·11956-11961
·
IF 7.394
Wenxiu Yang,Xiaoyu Yue,Xiangjian Liu,Junfeng Zhai,Jianbo Jia
A highly efficient N, S co-doped porous carbon ORR catalyst was simply designed in our report from ordered mesoporous carbon (OMC) and trace ionic liquids (ILs). The microstructure OMC was chosen as the template for improving the specific area, confining the ILs in the mesopores, and promoting the formation of the planar N and S doping. The resulting IL/OMC (IOMC) nanostructure exhibits comparable ORR activity and better stability than the commercial Pt/C catalyst in 0.10 M KOH solution, which makes it one of the best-performing metal-free carbon ORR catalysts. We deduced that the excellent ORR activity is attributed to the synergistic effect of N, S, and the ordered mesoporous structure. Interestingly, the ORR activity can be further boosted in both basic and acidic solutions after Fe doping into the IOMC nanostructures which clearly emphasizes that transition metal Fe is important for the construction of ORR active functional sites especially in acidic solution.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanoscale Research Letters
·
2019
·Vol. 14
·期 1
·1-11
·
IF 3.159
Guo Chaozhong,Li Yanrong,Xu Ya,Xiang Qin,Sun Lingtao,Zhang Weizhong,Li Wensheng,Si Yujun,Luo Zhongli
Synthesis of metal-free carbon-based electrocatalysts for oxygen reduction reaction (ORR) to replace the conventional platinum-based catalysts has currently become a hot topic of research. This work proposes an activation-assisted carbonization strategy for the fabrication of nitrogen-doped nanoporous carbon microfibers (Me-CFZ-900) with a high BET surface area (~ 929.4 m 2 g −1 ) via using melamine as a promoter/nitrogen source and bamboo-carbon biowastes as the carbon source with the help of a zinc chloride activator. Electrochemical tests showed that the Me-CFZ-900 material has exhibited excellent ORR electrocatalytic activity and long-term stability, and also displayed a quasi-four-electron ORR pathway in alkaline electrolyte. We also find that the graphitic-N may be the catalytically active site for the ORR, but the formation of planar-N can further help to promote the ORR activity for our catalysts. The results open a new space and provide a new idea to prepare valuable porous nanocarbon materials on the basis of carbonaceous solid wastes for catalysis of a wide range of electrochemical reactions in the future.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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