CARBON
·
2015
·
IF 6.196
Yunfeng Zhan,Jilin Huang,Zhipeng Lin,Xiang Yu,Dongrong Zeng,Xiaoxue Zhang,Fangyan Xie,Weihong Zhang,Jian Chen,Hui Meng
By doping graphene with iodine and ammonia, I and N co-doped graphene (ING) is prepared and used as metal free catalyst for the oxygen reduction reaction (ORR) both in alkaline and acidic media. The as-prepared catalyst exhibits striking activity in alkaline with an onset potential of 0.945 V (vs. RHE) which is the same with commercial Pt/C catalyst. In acidic media the ING shows a competitive activity. In both alkaline and acidic media the ORR is four-electron process catalyzed by ING. The superior ORR performance of the ING can be attributed to the synergetic doping effect of I and N. Based on its outstanding performance the ING can work as a metal free catalyst for fuel cell with much lower cost than currently used Pt/C catalyst.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 23
·11773-11780
·
IF 11.301
Qingyao Wu,Yan Liu,Jingjing Cao,Yue Sun,Fan Liao,Yang Liu,Hui Huang,Mingwang Shao,Zhenhui Kang
Photocatalytic water splitting to produce hydrogen and hydrogen peroxide is the main goal of photocatalysis. However, the reactions of both are water based and thus, it is extremely challenging to conduct both processes on one catalyst. Herein, a function-switchable metal-free catalyst was designed and synthesized through the polycondensation of procyanidin and 4-methoxybenzaldehyde. Impressively, the catalyst developed here not only split water to produce hydrogen via a four-electron reaction process in the absence of air, but also generated hydrogen peroxide by preferentially reducing oxygen via a two-electron pathway in air. The production rates of hydrogen and hydrogen peroxide reached 252.02 and 1385.42 μmol h−1 g−1, respectively. Through in situ transient photovoltage tests and kinetic analysis, a clear and fundamental understanding of the highly efficient and switchable functions was acquired for this photocatalyst. This study highlights the unique behavior and provides an insight into the design of function-switchable catalysts and the regulation of catalytic reactions.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Chang Liu,Shang Li,Yijing Xing,Huan Kang,Jinting Tan,Wei Guo,Mu Pan
Polyaniline (PANI) nanofibers were synthesized on carbon paper by electrochemical method, then heat-treated at temperatures of 800°C, 900°C, 1000°C and 1100°C to obtain a gas diffusion electrode (GDE). Fourier Transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the catalysts. The metal-free C-N catalyst with a reticular structure was coated on carbon paper. The ORR (oxygen reduction reaction) activity of metal-free C-N catalysts was evaluated by cyclic voltammetry (CV) and rotating disk electrode (RDE) in HClO 4 . The results showed that the catalysts heat-treated at 1000°C had the best ORR activity and better stability compared with the commercial Pt-based catalysts in acidic medium. The result of XPS showed that the activity of metal-free C-N catalysts was related to the pyridinic-type nitrogen. Finally, the advantages and disadvantages of these catalysts were discussed for further investigation.
研究领域:
材料科学
·
电化学
·
能源技术
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 31
·13877-13884
·
IF 3.591
Chen Xing,Yan Zhang,Yang Gao,Yijun Kang,Shiguo Zhang
The selective oxidation of alcohols is traditionally catalyzed by precious metals, where high cost, low selectivity, poor stability, and environmental concerns have hindered their wide application. Here we report a nitrogen and phosphorus co-doped microporous carbon (NPMC) as an efficient catalyst towards the selective oxidation of benzyl alcohol. NPMC is fabricated from one-step pyrolysis of an aerogel derived from the polymerization of p-phenylenediamine with phytic acid. The optimized NPMC exhibits high efficiency and universality for the selective oxidation of alcohols in an aqueous environment using air as the oxidant, due to its large surface area (∼676 m2 g−1), good hydrophilicity, and suitable microporous structure (1–2 nm), as well as the concerted effects between N and P doping. 50 mg of the catalyst is sufficient for affording almost quantitative amounts of benzyl alcohol oxidized to benzaldehyde without organic solvents and co-catalysts, and its catalytic performance is the best among the metal-free catalysts reported. The heterogeneous catalyst is also perfectly stable, and can be reused several times without significant loss of activity and selectivity.
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
Catalysts
·
2023
·Vol. 13
·期 5
·904
·
IF 3.9
Peixu Sun,Xiaoxiao Wang,Mingjian Zhu,Naveed Ahmad,Kai Zhang,Xia Xu
In this study, a facile one-step method via pyrolysis was used to prepare nitrogen self-doped metal free catalysts derived from inexpensive biomass-chitin for an electrochemical CO2reduction reaction (CO2RR). The microstructure, surface area, defect and N type in the catalysts were analyzed by BET, Raman, XPS, SEM and TEM. The sustainable chitin-based electrocatalyst prepared under optimized conditions has a surface area of 1972 m2/g and can convert CO2into CO with FECOof ~90% at a potential of −0.59 V (vs. RHE). This good CO2RR performance results from plentiful active sites due to a high surface area, rich ultra-micropores that are beneficial to CO2adsorption, abundant mesopores for CO2transport improvement, a high content of pyridinic and graphitic nitrogen that is favorable for a CO2reduction reaction and a low interfacial charge transfer resistance leading to a rapid electron transfer rate from the catalyst to CO2. This study shows the feasibility of N self-doped biomass-derived catalysts for CO2RR with the potential for large-scale industrial applications.Keywords:biomass;CO2electroreduction;nitrogen self-doped catalyst;metal free catalysts
研究领域:
材料科学
·
环境科学
·
催化
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Yi Wang,Yuxin Wang,Yueting Wang,Jin Zhao,Yang Gao,Jingyi Liang,Tianjun Hu,Baoliang Lv,Ergui Luo,Jianfeng Jia
Carbon-based metal-free materials are emerging as leading candidates to replace noble-metal catalysts in the oxygen reduction reaction (ORR). Herein, we introduce a facile secondary carbonation technique for fabricating Se and N co-doped metal-free catalysts using a zeolite imidazole framework (ZIF-8) as the precursor. The optimal electrocatalyst, designated SeNC-900, exhibited good ORR performance under both alkaline and acidic conditions, with half-wave potentials of 0.864 V and 0.731 V (vs. RHE), respectively. Density functional theory (DFT) calculations reveal that the enhanced activity of SeNC-900 originates from Se doping, which triggers an increase in the intrinsic defects of sp 3 -hybridized C. Concurrently, the sp 3 -hybridized C, in concert with Se dopant, modulates the electronic structure of the active C atoms. This work not only underscores the significance of tuning the electronic structure to boost catalytic performance by enriching intrinsic defects but also presents a fresh insight into the effect of heteroatom doping on carbon-based materials for electrocatalysis.
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
Nature Communications
·
2021
·Vol. 12
·期 1
·1-10
·
IF 14.919
Wu Qingyao,Cao Jingjing,Wang Xiao,Liu Yan,Zhao Yajie,Wang Hui,Liu Yang,Huang Hui,Liao Fan,Shao Mingwang,Kang Zhenghui
Artificial photosynthesis of H 2 O 2 from H 2 O and O 2 , as a spotless method, has aroused widespread interest. Up to date, most photocatalysts still suffer from serious salt-deactivated effects with huge consumption of photogenerated charges, which severely limit their wide application. Herein, by using a phenolic condensation approach, carbon dots, organic dye molecule procyanidins and 4-methoxybenzaldehyde are composed into a metal-free photocatalyst for the photosynthetic production of H 2 O 2 in seawater. This catalyst exhibits high photocatalytic ability to produce H 2 O 2 with the yield of 1776 μmol g −1 h −1 ( λ ≥ 420 nm; 34.8 mW cm −2 ) in real seawater, about 4.8 times higher than the pure polymer. Combining with in-situ photoelectrochemical and transient photovoltage analysis, the active site and the catalytic mechanism of this composite catalyst in seawater are also clearly clarified. This work opens up an avenue for a highly efficient and practical, available catalyst for H 2 O 2 photoproduction in real seawater.
研究领域:
环境科学
·
材料科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS CHEMISTRY
·
2012
·Vol. 22
·期 15
·7456-7460
·
IF 5.968
Chengfei Yuan,Wufeng Chen,Lifeng Yan
Metal-free catalysts are essential for various chemical reactions in industrial chemistry. Amino-functionalized carbon is a cheap and environmentally friendly solid basic catalyst. Here, NEt3-graphene solid basic catalyst has been synthesized through a consecutive deprotonation/carbometalation and electrophilic substituent. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), elemental analyses, thermal analyses, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) studies confirmed the formation of the target structure. Catalytic hydrolysis of ethyl acetate reveals that the amino-grafted graphene has a high catalytic activity.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
ChemSusChem
·
2019
·Vol. 12
·期 22
·5041-5050
·
IF 7.804
Ming Zhao,Tianhao Li,Lichao Jia,Huilin Li,Weiyong Yuan,Chang Ming Li
Graphical Hydrothermal self-assembly : Graphene-supported carbon with an ultrahigh N-doping level is controllably synthesized by facile and economical in situ self-assembly of a glucaminium-based ionic liquid on pristine graphene under hydrothermal conditions. As an electrocatalyst, it exhibits superior catalytic activity and durability in the oxygen evolution reaction. For the first time, graphene-supported N-doped carbon (G@NC) with a high degree of N doping was synthesized by in situ self-assembly of a glucaminium-based ionic liquid on pristine graphene under hydrothermal conditions. This 2D, metal-free nanohybrid exhibited much higher catalytic activity than most reported metal-free catalysts for the oxygen evolution reaction (OER) and even state-of-the-art Ir- and Ru-based catalysts because the high content of graphitic N greatly increased the number of OER-active sites, the pristine graphene significantly promoted the OER activity of the C sites adjacent to the graphitic N atoms, and N-doped graphitic carbon remarkably enhanced the charge-transfer rate. This work not only creates a facile and economical approach to controllably fabricate pristine-graphene-supported carbon with a high N-doping level for the development of highly efficient metal-free OER catalysts but also provides insight into the mechanisms for both the in situ self-assembly and the high OER catalytic activity of G@NC.
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
GREEN CHEMISTRY
·
2022
·Vol. 24
·期 3
·1294-1301
·
IF 11.034
Chumeng Fan,Lei Zhang,Chenxi Zhu,Jingjing Cao,Yunlong Xu,Ping Sun,Guixiang Zeng,Wei Jiang,Quanxing Zhang
Developing efficient metal-free catalyst for the glycolysis of waste poly(ethylene terephthalate) (PET) with ethylene glycol (EG) has attracted increasing attention due to the demanding requirement for high-quality monomer used in regeneration. Herein, a new kind of efficient metal-free catalyst phosphazene base (t-BuP2) was developed through the combination of theoretical prediction and experimental verification approaches, which could achieve 100% conversion of PET and obtain BHET yield (92.7%) comparable to metal-based catalysts. The high efficiency of t-BuP2 comes from the facile generation of EG−, which has a strong ability to break the PET chain through a nucleophilic attack on the carbonyl group. t-BuP2 was selected as the catalyst based on the theoretical evaluation of the proton abstract ability of various bases through natural bond orbital analysis and reaction energy calculations, which could deprotonate EG barrierlessly to produce EG−. Next, the nucleophilic attack of EG− on the carbon atom of the carbonyl group in PET occurs, which greatly weakens the strong C–O bond on the PET chain. Then, the C–O bond was cleaved (rate-determining step) with the Gibbs activation energy and Gibbs reaction energy of 20.2 and −3.8 kcal mol−1, respectively, which was followed by the glycolysis step to produce BHET. Furthermore, t-BuP2 was found to have high regeneration performance, which could be recycled at least seven times without an apparent decrease in activity.
研究领域:
化学工程
·
材料科学
·
催化反应
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2019
·Vol. 9
·期 14
·3753-3762
·
IF 5.726
Xianliang Qiao,Zhiqiang Zhou,Xinyu Liu,Chaoyue Zhao,Qingxin Guan,Wei Li
Graphitic carbon nitride (denoted as “g-C3N4”), as a graphite-like CN material, is widely used in catalysis. In this paper, a fragmentary g-C3N4 framework with a porous structure and rich nitrogen defects was synthesized for acetylene hydrochlorination, using melamine formaldehyde (MF) resin as an oxygen-containing precursor. The fragmentary g-C3N4 shows a highly efficient activity with acetylene conversion reaching 94.5%, which is 30 times higher than that of pure g-C3N4 prepared by direct pyrolysis of melamine. Both experimental and characterization studies by XRD, XPS and TG-MS reveal that the high activity of the catalyst is mainly derived from the porous structure and rich nitrogen defects, which are attributed to the etching of the g-C3N4 framework by oxygen species in the MF resin. Moreover, density functional theory (DFT) calculations demonstrated that the nitrogen defects in the g-C3N4 framework greatly improved the adsorption of HCl and acetylene, and at the same time significantly reduced the energy barrier from 62.0 to 38.1 kcal mol−1 at the rate-determining step.
研究领域:
催化化学
·
材料科学
·
理论计算化学
✓ 已验证
产品关联
DOI
高影响因子
Nano Energy
·
2018
·
IF 13.12
Jianbing Zhu,Meiling Xiao,Ping Song,Jing Fu,Zhao Jin,Liang Ma,Junjie Ge,Changpeng Liu,Zhongwei Chen,Wei Xing
Metal-free electrocatalysts have eluded widespread adoption in polymer electrolyte membrane fuel cells due to their far inferior catalytic activity than most non-precious metal-N-C counterparts (M-N x -C) for oxygen reduction reaction (ORR), despite their distinct advantages over the M-N x -C catalysts, including lower cost and higher durability. Herein, we develop a rational bottom-up engineering strategy to improve the ORR performance of a metal-free catalyst by constructing a three-dimensional ultrathin N, P dual-doped carbon nanosheet . The resultant catalyst represents unprecedented ORR performance with an onset potential of 0.91 V, half-wave potential of 0.79 V. Impressively, a maximum power output at 579 mW cm −2 is generated in the fuel cell test, the best among reported metal-free catalysts and outperforms most of the M-N x -C catalysts. The outstanding catalytic performance results from the highly active polarized carbon sites which are induced by selective graphitic nitrogen and phosphorous dual doping . Our findings provide new directions for the exploration of alternatives to Pt and bring a renew interests in the metal-free catalysts.
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
危险品化学品经营许可证（带存储）