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
NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 42
·19775-19781
·
IF 3.3
Xueyan Wu,Yang Yang,Yan Lv,Xiuli Zhang,Jiaxin Li,Jixi Guo
The development of efficient and stable catalysts for the oxygen reduction reaction (ORR) is crucial to enable practical large-scale application of Zn–air batteries (ZABs). This study investigates the utilization of N, S co-doped coal-based activated carbon materials, synthesized through facile reactions, which exhibit high specific surface area and abundant active sites. The results of material characterization and experiments indicate that co-doping with N and S can effectively modify the charge distribution of coal-based activated carbon materials, increase the active sites, and ultimately enhance their performance in the oxygen reduction reaction (ORR). The N, S-AC catalyst exhibits remarkable catalytic activity for the ORR in alkaline electrolytes, demonstrating a high half-wave potential (E1/2 = 0.79 V), ultimate current density (jL = 6.35 mA cm−2) and stability, as well as considerable tolerance to methanol. The N, S-AC-based ZAB also demonstrates exceptional performance, achieving a maximum power density of 142 mW cm−2 and a specific capacity of 804 mA h gZn−1. This study not only simplifies the preparation process for heteroatom-doped coal-based activated carbon catalysts but also explores practical applications for ZABs.
研究领域:
材料科学
·
电化学
·
能源存储与转换
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Yuxian Wang,Jiaxin Xi,Xiaoguang Duan,Weiguang Lv,Hongbin Cao,Chunmao Chen,Zhuang Guo,Yongbing Xie,Shaobin Wang
Metal-free mesoporous graphitic frameworks with built-in nanotubes (CPGs) were synthesized via facile co-pyrolysis of cyclodextrin and a cobalt salt with subsequent acid pickling to remove the embedded metal species. Due to the high graphitic degree and built-in few-layer nanotubes, the as-synthesized carbonaceous materials possess a higher catalytic ozonation activity than that of the state-of-the-art carbon nanotubes (CNTs) and LaMnO 3 perovskite catalysts for the destruction of different aqueous contaminants. For recalcitrant oxalic acid removal, 50 mg L −1 oxalic acid was completely degraded in 20 min. Compared with other nanocarbons, the as-synthesized materials also demonstrated robust structural stability and reusability. The electron paramagnetic resonance (EPR) and selective radical quenching tests revealed that the destruction of the aqueous organics predominantly relied on surface-adsorbed complexes (O* ad and O 2 *) from activated ozone molecules. Owing to the occurrence of this surface oxidation pathway, the compatibility of the CPGs/O 3 system was significantly enhanced for treatment of real wastewater, where the inorganic anions and organic natural organic matter would inhibit radical oxidation as radical scavengers. Furthermore, by employing organics with different ionization potentials (IPs) as the target pollutants, the CPGs/O 3 system was discovered to obtain a high oxidation potential.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
Environmental Science-Advances
·
2023
·
IF 0
Min Li,Xudong Liu,Zhinan Xie,Chunfang Du,Yiguo Su
A one-step thermal polymerization approach was adopted to combine C3N5 with montmorillonite nanosheets (MMT Ns) to form xCN-MMT for the degradation of pollutants in water. Benefitting from the abundant hydroxyl groups on the MMT surfaces, double defects (–CN and N defects) were introduced in xCN-MMT catalysts to promote the adsorption of tetracycline (TC), peroxymonosulfate (PMS), and oxygen. 10CN-MMT exhibited superior adsorption performance toward TC, with the adsorption capacity being 5.65-fold that of MMT Ns and 2.64-fold that of C3N5. Further, 10CN-MMT exhibited better PMS activation performance than MMT Ns and C3N5, which could degrade 95% of TC within 120 min. Moreover, the total organic carbon (TOC) removal efficiency of the present system reached 81.1%, and the chemical oxygen demand (COD) decreased from 50.7 to 12.2 mg L−1. The degradation process of TC was characterized using liquid chromatography-tandem mass spectrometry (LC-MS), and a reasonable degradation pathway and catalytic mechanism were given by combining with active species analysis. The toxicological analysis of the degradation products also showed a significant decrease in toxicity. The degradation experiments in different water environments were also simulated, and it was found that 10CN-MMT showed good adsorption effects. This study provides a green metal-free clay-based catalyst and shows good applicability in removing antibiotics.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
DOI
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2025
·
IF 5.4
Yunchao Ma,Yuxin Yao,Shengnan Qi,Chuanxue You,Yue Zhou,Keyu Cui,Guangbo Che,Xiaotian Yang,Chunbo Liu
In the context of the global energy transition, the key challenge of electrocatalytic hydrogen production technology is to develop high-performance and low-cost catalysts to achieve efficient HER. In this study, we created a metal-free, in situ carboxylic acid COF named JLNU-314, using 4,4''-diformyl-[1,1′:4′,1''-terphenyl]-2′,5′-dicarboxylic acid (TP-COOH) as the building block through a solvothermal process. JLNU-314 exhibits high crystallinity, robust chemical stability, and superior hydrophilicity. JLNU-314 exhibits a low overpotential of 166 mV at a current density of 10 mA cm −2 in alkaline electrolytes, outperforming the performance of JLNU-315, which does not possess carboxyl groups. Theoretical calculations reveal that the carboxyl group (─COOH) maintains COF's planar structure, enhances hydrophilicity, and offers hydrogen bonding sites. As a polar functional group, it creates a directional electric field, accelerating charge separation and migration, optimizing alkaline HER performance. This represents the first in situ carboxylic acid-based COF electrocatalytic system for HER. It provides a new idea for the development of electrocatalysts in the future.
研究领域:
能源材料
·
电化学
·
纳米技术
·
催化
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2024
·
IF 15.7
Jingya Guo,Wei Liu,Wenzhe Shang,Duanhui Si,Chao Zhu,Jinwen Hu,Cuncun Xin,Xusheng Cheng,Songlin Zhang,Suchan Song,Xiuyun Wang,Yantao Shi
Endowing metal-free graphitic carbon electrodes with high electrocatalytic reactivity is a field of intense research, but remains elusive. Here, we introduce a prototypical edge-plane-site-specific engineering strategy on “herringbone” multi-walled carbon nanotubes by performing an intercalation-exfoliation and truncation process in molten inorganic salts. Controllable synthesis of the target H-MWCNTs-MS with fully exposed edge-plane sites on both the outer surface and inner channels was demonstrated. in-situ infrared spectroscopic study supports the theoretically energetic “edge-state” and identifies the reconstructed ketone/carboxyl-terminated edge sites under oxygen evolution reaction (OER) conditions. These oxygenated edge-plane sites boost charge redistribution and interlayer coupling, which essentially govern the synergistic catalysis, as evidenced by combined theoretical, electrokinetic, and H/D isotopic studies. Benefiting from the dense reactive sites and efficient electron tunneling, the H-MWCNTs-MS demonstrated impressive OER activity with an overpotential of 236 mV at a current density of 10 mA cm −2 in alkaline media, outperforming most state-of-the-art metal-free electrocatalysts reported to date. Furthermore, the catalyst displayed no noticeable degradation during 100 h of operation, indicating its potential for practical applications.
研究领域:
材料科学
·
电化学
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2024
·
IF 2.3
Sun Min,Chu Siyu,Guo Dongfang,Jiao Xinyu,Wang Haiyan,Wang Lingli,Li Zijiong,Jiang Liying
Rising energy demand has forced to look for new ways to convert energy. Graphene quantum dots (GQD) has received extensive attention in many fields due to their low toxicity, abundant active sites, sound water solubility and photoluminescence stability. Here, a fluorine-nitrogen co-doped GQD (C-GQD) is synthesized for efficient oxygen reduction reaction (ORR) catalysts. The incorporation of fluorine and nitrogen atoms changed the electronic structure of the carbon atom, resulting into synergistic enhancement of catalytic performance toward ORR. Electrochemical studies of the ORR showed that the initial potentials of C-GQD were positively shifted by 200 mV and 170 mV compared with those of GQD and N-GQD, respectively, and the half-wave potentials were positively shifted by 200 mV and 180 mV, which were comparable to that of 20% Pt/C. The CV curves underwent only slight fluctuations after 10,000 cycle tests. The obtained results provide important insights into the use of metal-free catalysts with GQDs as carriers as promising electrocatalysts for proton exchange membrane fuel cells with low cost and easy preparation procedures. Graphical Abstract
研究领域:
材料科学
·
电化学
·
能源转换
✓ 已验证
产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2020
·Vol. 31
·期 44
·445402
·
IF 3.551
Ranran Cui,Yukun Xiao,Chengxing Li,Yuyang Han,Guiqin Lv,Zhipan Zhang
Lithium–oxygen batteries (LOBs) are considered as next-generation energy storage devices owing to their high-energy densities, yet they generally suffer from low actual specific capacity and poor cycle performance. To solve these issues, a range of electrocatalysts have been introduced in the cathode to reduce the overpotential during charge/discharge cycles and minimize unwanted side reactions. Due to relative high costs and limited reserves of noble metals and their compounds, it is important to develop low-cost and efficient metal-free electrocatalysts. Here, we report a simple method to prepare three-dimensional porous polyaniline (PANI)/reduced graphene oxide foams (PPGFs) with different PANI contents via a two-step self-assembly process. When these foams are tested as the cathode in LOBs, the device using the PPGF with 50% PANI content exhibits a discharge capacity up to 36 010 mAh g−1 and an excellent cycling stability (260 cycles at 1000 mAh g−1 and 500 cycles at 500 mAh g−1), provid ing new insights into the design of next-generation metal-free cathodes for LOBs.
研究领域:
材料科学
·
能源存储技术
·
电化学
✓ 已验证
DOI
高影响因子
ChemCatChem
·
2019
·Vol. 11
·期 22
·5495-5504
·
IF 4.495
Chuang Zhang,Ben Ma,Yingke Zhou
Graphical 3D N-doped CNT aerogel is facilely synthesized by pyrolysis of the template polymerized PPy, and displays superior ORR activity and stability due to the dominant role of the graphitic-N and the graphitization degree of the carbon materials. A novel N-doped carbon nanotube aerogel has been synthesized by pyrolysis of the three-dimensional tubular polypyrrole networks and evaluated as a metal-free electrocatalyst for the oxygen reduction reaction. The carbon aerogel catalysts are pyrolyzed at 500 °C (PPy/C-500), 700 °C (PPy/C-700), 900 °C (PPy/C-900) and 1050 °C (PPy/C-1050), and display the pyrolyzed temperature-dependent activity and stability. The catalytic activity is increased with the increase of pyrolysis temperature from 500 °C to 1050 °C, ascribed to the high electronically conductive graphitic phases, the thin wall of the three-dimensional tubular carbon aerogel framework and the increased effective active sites. The nitrogen content is reduced with the increase of pyrolysis temperature, and which plays an important role in the stability of the pyrolyzed catalyst. After 1500 cycles, the PPy/C-1050 catalyst shows more positive half-wave potential than the commercial Pt/C catalyst, and displays a quasi-four-electron pathway toward the oxygen reduction reaction in the acid solution. This work provides an effective strategy for preparing the low cost and metal-free N-doped carbon aerogel catalyst from the conjugated conducting polymer, to achieve high activity and stability.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2017
·
IF 0
Yepeng Xiao,Jincheng Liu,Kaihong Xie,Weibin Wang,Yanxiong Fang
Despite extensive development efforts on new catalysts for cyclohexane oxidation, current commercial processes are still desirable to further decrease the economic and environmental costs in the oxidation procedures. In this study, the catalyst properties of metal-free functionalized graphene oxide (GO) in the selective oxidation of cyclohexane is investigated to understand the effects of structure, functional groups and oxygen-containing groups. Both GO sheets and nano graphene oxide (NGO) sheets possess high cyclohexane conversions of 16.7% and 17.7% comparable to that of metal catalysts in the aerobic oxidation of cyclohexane. The higher catalytic activity of NGO sheets is caused by the smaller size and the higher content of −COOH. Within the oxygen-containing groups, the carboxylic acid groups on the surfaces of GO are supposed as the active site for the generation of O 2 − radical, which is the active oxygen species in this catalytic oxidation process.
研究领域:
催化化学
·
材料科学
·
环境化学
✓ 已验证
产品关联
DOI
DALTON TRANSACTIONS
·
2016
·Vol. 45
·期 23
·9582-9589
·
IF 4.177
Junchuan Zhang,Junshuang Zhou,Li Hou,Faming Gao
Nitrogen and sulfur co-doped monodisperse carbon microspheres (NS-CMSs) have been successfully synthesized as a new kind of outstanding metal-free ORR catalyst through a one-pot solvothermal reaction. The as-synthesized heteroatom-doped CMSs have been systematically characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) and by using Raman spectra and nitrogen adsorption and desorption isotherms. Compared with the commercially available 20 wt% Pt/C catalyst, the as-prepared NS-CMSs showed a much better tolerance toward methanol crossover and long-term operation stability for ORR in an alkaline medium.
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
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Chuan Hu,Qinrui Liang,Yuting Yang,Qiming Peng,Zuyang Luo,Jiaxin Dong,Tayirjan Taylor Isimjan,Xiulin Yang
Heteroatom-doped metal-free carbon catalysts for oxygen reduction reactions have gained significant attention because of their unusual activity and economic cost. Here, a novel N/P co-doped porous carbon catalyst (NPPC) with a high surface area for oxygen reduction reaction (ORR) is constructed by a facile high-temperature calcination method employing ZIF-8 as the precursor and red phosphorus as the phosphorus source. In particular, ZIF-8 is firstly calcined to obtain N-doped carbon (NC) followed by further calcination with red phosphorus to obtain NPPC. Ultraviolet photoelectron spectroscopy (UPS) analysis shows that the ultra-low amount of P doping could significantly decrease the work function from 4.32 to 3.86 eV. The resultant catalyst exhibits a promising electrocatalytic activity with a half-wave potential ( E 1/2 ) of 0.87 V and a limiting current density ( J L ) of 5.15 mA cm −2 . Besides, it also shows improved catalytic efficiency and excellent durability with a negligible decay of J L after 2000 CV cycles. Moreover, aqueous and solid-state flexible zinc-air batteries (ZAB) using the catalyst show a promising application potential. This work provides new insight into developing P/N-doped metal-free carbon ORR catalysts.
研究领域:
材料科学
·
能源化学
✓ 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）