POLYMER
·
2021
·
IF 4.43
Zhen Li,Yunfei Zhi,Yonghao Ni,Hongying Su,Yingju Miao,Shaoyun Shan
Copolymerization of SO 2 with epoxide into the poly(cyclohexene sulfite) (PCS) is crucial due to the severe harm of SO 2 to the environment and the wide application need of the PCS product. However, the copolymerization tends to exhibit low conversion rate even under harsh conditions. The introduction of high-efficiency catalysts is an efficient way to solve the problem of limitation of SO 2 copolymerization. Herein, the novel and metal-free Schiff-base network (SNW) material, SNW-KUST1, was successfully designed and structurally characterized, which exhibits an excellent catalytic performance for the copolymerization of SO 2 and cyclohexene oxide with a record PCS selectivity of 93%. In comparison with the SNW-1, the catalytic activity of SNW-KUST1 is greatly improved, which can be attributed to the introduction of hydroxyl and increasing specific surface area. Moreover, the SNW-KUST1 can be reused more than 6 times without obvious decrease of the catalytic activity, and presents a wide applicability to various epoxides. A possible mechanism for the SO 2 copolymerization over SNW catalysts is proposed which includes the epoxide adsorption, ring-opening of epoxide, SO 2 insertion and the formation of PCS. It is an optimistic hope that this investigation can give a valuable guideline to design SNW materials with π-π conjugated and nitrogen-rich building blocks for the SO 2 copolymerization.
研究领域:
化学工程
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Xiudan Liu,Longjun Rao,Yuyuan Yao,Haixiang Chen
Developing an efficient and metal-free bifunctional catalyst for the simultaneous degradation of antibiotic and reduction of Cr (VI) has been regarded as increasingly attractive yet challenging objectives in the environmental catalysis field. Herein, phosphorus-doped carbon fibers (P-CFs) was innovatively prepared by doping and calcination methods, characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy . Sulfamethoxazole (SMX) as the target contaminant was selected to evaluate the catalytic activity of P-CFs in PMS activation , over 90% SMX removal and 82.75% mineralization were high-efficiently achieved in the P-CFs/peroxymonosulfate (PMS) system. Particularly, P-CFs/PMS system exhibited a superior catalytic oxidation performance over a wide pH range (3.5–9.5) and even in the complicated water matrix. Surprisingly, the presence of humic acid (HA) in the P-CFs/PMS system could achieve about 2 times enhancement on SMX removal, different from most reports about the inhibition of HA in PMS activation. More importantly, Brunauer−Emmett−Teller (BET) method and XPS analysis revealed that the highly toxic Cr (VI) could be reduced to Cr (III) by P-CFs. Furthermore, electron spin resonance (ESR) combined with various trapping agents demonstrated that SO 4 • − , •OH and 1 O 2 . were generated and participated in the SMX degradation , while the free electron in P-CFs played a main role in Cr (VI) reduction. This finding not only provided a high-efficiency strategy in the treatment of wastewaters containing organic contaminants and heavy metals Cr (VI), but might open new insights into an innovative metal-free catalyst in environment remediation.
研究领域:
环境科学
·
催化材料
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Zichen Zhang,Donglin Yang,Jiaqiang Wang,Chaoting Deng,Hengjun Gai,Meng Xiao,Tingting Huang,Quanhong Zhu,Hongbing Song
Ionic liquids (ILs) are unique substances with unique ionic sites. They are regarded as one of the most promising green solvents and catalysts in the 21st century. In this work, the synthesis of imidazolium-based ILs as metal-free catalysts by molecular design is reported for the first time. By using the ILs as precursors, hyper-crosslinked poly(ionic liquid) (HCPIL) was synthesized by Friedel–Crafts alkylation reaction. These metal-free catalysts can effectively activate ethanolamine for the hydrogenation of nitrobenzene, and they have definite active sites. As the synthesized HCPIL-Cl has a rich porous structure and IL structural units, it could maintain the catalytic activity of ILs and recover them via efficient facile filtration and washing. Density functional theory (DFT) calculation suggested that the imidazolium structure is essential to ethanolamine activation. The calculated results of DFT agree well with the experimental results. The hydrogenation of nitrobenzene has many intermediates whose selectivity can be regulated by different gas atmosphere or alkaline environments. This work provides a promising method for the design of metal-free catalysts.
研究领域:
催化化学
·
绿色化学
·
计算化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2022
·
IF 12.92
Wenjuan Zhang,Pei Jing,Juan Du,Shujie Wu,Wenfu Yan,Gang Liu
Carbon catalysis is an attractive metal-free catalytic transformation, and its performance is significantly dependent on the number of accessible active sites. However, owing to the inherent stability of the C–C linkage, only limited active sites at the edge defects of the basal plane can be obtained even after a harsh oxidation treatment . In this study, the concept of interfacial interactions was adopted to propose an efficient strategy to develop highly active carbon catalysts. The alumina/carbon interface formed in situ acted as a cradle for the generation of oxygen-containing functional groups. In the absence of oxidation treatment, the concentration of oxygen-containing functional groups and the specific surface area can reach 1.27 mmol·g −1 and 2340 m 2 ·g −1 , respectively, which are significantly higher than those of carbon prepared by traditional hard template methods. This active carbon shows a significant enhancement in catalytic performance in the oxidative coupling of amine to imine, about 22-fold higher than that of a well-known graphite oxide catalyst. Such interfacial interaction strategies are based on sustainable carbon sources and can effectively tune the porous structure of carbon in the micro- and meso-ranges. This conceptual finding offers new opportunities for the development of high-performance carbon-based metal-free catalysts.
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
Journal of Materials Chemistry A
·
2018
·Vol. 6
·期 31
·15310-15319
·
IF 9.931
Zhou Chen,Ting-Ting Fan,Xiang Yu,Qiu-Ling Wu,Qiu-Hui Zhu,Li-Zhong Zhang,Jian-Hui Li,Wei-Ping Fang,Xiao-Dong Yi
Efficient and economical photocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are required to replace expensive metal-based catalysts used in water splitting devices. Herein, we have developed an inexpensive route to synthesize a carbon-rich graphitic carbon nitride (C-rich g-C3N4) with both nitrogen vacancies and a porous structure, which, as a highly efficient photo-induced water splitting catalyst, can meet current demands. The effects of the porous structure, nitrogen vacancies and rich amount of carbon on the electronic band structure and charge transport of g-C3N4 are systematically elucidated. The C-rich g-C3N4 can not only effectively enhance the absorption of visible light, but can also improve the majority carrier mobility and promote photoelectron transport through the defect-induced mid-gap and multiple conductive carbon rings, thus synergistically elongating the diffusion length and lifetime of the photocarriers. Importantly, the metal-free C-rich g-C3N4 photocatalyst not only demonstrates a higher solar-driven hydrogen production performance, which is over 20.5 times that of pristine g-C3N4, but also exhibits an outstanding stability with minimal loss of catalytic activity.
研究领域:
材料科学
·
光催化
·
能源化学
·
纳米材料
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半导体物理
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环境功能材料
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Wei Fan,Linpiao Cheng,Chunyang Dan,Shengjun Wang,Shenbin Zheng,Huimin Sui,Yun Zhang,Guangming Jiang,Wenyang Fu,Liang Ao,Xiaoshu Lv
Electrocatalytic hydrodechlorination (ECHD) represents a sustainable strategy for deactivating chlorinated antibiotics through hydrogenolysis of C Cl bonds. However, its widespread application is hindered by the scarcity of cost-effective catalyst, as well as their insufficient efficiency in treating trace antibiotics. Herein, a porous superhydrophobic biochar was fabricated from rice straw via a stepwise process of thermal pyrolysis, acidic etching and chemical reduction, which demonstrates an exceptional adsorption capacity of 575.0 mg g −1 for florfenicol (FLO) and a remarkable mass activity of 1.1 mg min −1 g −1 in ECHD of 20.0 mg L −1 FLO at −0.6 V. This performance not only exceeds reported biochars produced with fewer processing steps, but also surpasses several metal-based catalysts. Our biochar was further confirmed competent in degrading more dilute FLO (2 mg L −1 ) in contaminated lake water. Mechanistic investigations reveal that the outstanding ECHD performance of the biochar stems from its superhydrophobic and porous property, promoting adsorptive enrichment of trace antibiotics. In contrast, the carbon defects and oxygen-containing groups introduced during thermal pyrolysis impede electron transfer between the biochars and pollutants, due to unfavorable orbital occupancy, elevated work function and increased surface polarity within biochar. These findings emphasize the necessity of chemical reduction to remove these interfering moieties, while confirming the promise of porous and superhydrophobic biochars as sustainable catalysts for antibiotic-contaminated water remediation.
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2021
·
IF 6.901
Bingnan Wang,Di Chen,Hongzhou Dong,Yan Huang,Lina Sui,Beili Pang,Shuai Ma,Lifeng Dong,Liyan Yu
Metal-free and metal-based electrocatalysts are designed according to different principles, but there should be an intimate connection between them. In this work, a simple yet cost-effective strategy is proposed to etch and disperse graphene oxide (GO) and porous hollow carbon shell loaded with CoS 2 (PHCS-CoS 2 ) into a porous skeleton similar to "highway" to effectively "trap" graphene oxide quantum dots (GOQDs) via a one-step process. Due to interconnected networks and size effects, N-S codoped porous graphene carbon sheets along with GOQDs (N,S-PGCS(QDs)) have eminent properties for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Furthermore, the metal-free system can be transformed to a metal-based electrocatalyst (N,S-PGCS(QDs)-Co 1-x S/Co 9 S 8 ) loaded with Co 1-x S/Co 9 S 8 nanohybrids , which demonstrates superior electrocatalytic characteristics than Pt/C+RuO 2 in terms of half-wave potential (0.85 V), current density, methanol tolerance, the potential difference between E ORR1/2 and E OER10 (0.68 V), and long-term stability. The Zn-air battery assembled with N,S-PGCS(QDs)-Co 1-x S/Co 9 S 8 shows a large peak power density of 168.2 mW cm −2 , a capacity performance up to 817.9 mAh g −1 , an ultra-high specific energy density of 973.3 Wh kg Zn −1 and considerable durability. The findings above may provide a scalable synthetic guidance and a novel direction for the design of metal-free and metal-based electrocatalysts.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CARBON
·
2019
·
IF 7.466
Jian Yang,Fei Xiang,Heng Guo,Liping Wang,Xiaobin Niu
It has been a major challenge to dispose the unrenewable high-performance polymers (HPPs) after their large-scale application in our society. Here we report an approach to reuse one kind of HPP as carbon and sulfur sources in synthesizing nitrogen and sulfur dual-doped honeycomb-like porous carbon catalysts for oxygen reduction reaction. Briefly, poly(phenylene sulfide sulfone) with S atoms in polymer chain as sulfur source, dicyandiamide as nitrogen source and SiO 2 nanoparticles as hard-template are pyrolyzed in designed temperatures under argon atmosphere. Then N, S dual-doped carbon catalysts (N, S@C) are obtained after subjected etching treatment. By adjusting moderate amount of SiO 2 , the optimized catalyst (denoted as N, S@C M -1000) pyrolyzed at 1000 °C, shows best ORR electrocatalytic activity in alkaline environment. Impressively, when N, S@C M -1000 is used as a cathode catalyst, the corresponding assembled zinc-air batteries exhibit a maximum power density of 90 mW cm −2 with long-term durability and high rate capacity. Therefore, this work provides a feasible way to resolve and reuse the unrenewable HPP for synthesizing heteroatom doped carbon-based catalysts.
研究领域:
材料科学
·
环境科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Shizong Wang,Lejin Xu,Jianlong Wang
Metal-free carbonaceous persulfate activator has received increasing attention recently. Graphitic carbon nitride (g-C 3 N 4 ) is one of the promising carbon materials due to excellent stability and low cost, but its activity for peroxymonosulfate (PMS) activation is low. In this study, g-C 3 N 4 was modified with oxygen atoms in the first step (O-g-C 3 N 4 ), then exfoliated via sequential thermal and ultrasound treatment to produce O-g-C 3 N 4 nanoflakes to increase its catalytic activity to activate PMS. In the presence of O-g-C 3 N 4 nanoflakes, SMX degradation rate achieved 0.079 min −1 , which was much faster than that in the presence of pristine g-C 3 N 4 (0.0083 min −1 ) and untreated O-g-C 3 N 4 (0.012 min −1 ). The surface-bound radicals and direct electron transfer between SMX and PMS contributed to the SMX degradation. Density functional theory (DFT) simulation revealed that oxygen-doping changed the charge distribution. Furthermore, O-g-C 3 N 4 nanoflakes had higher adsorption energy for PMS and SMX (0.518 kcal/mol) than pristine g-C 3 N 4 (0.304 kcal/mol), which contributed to the enhanced PMS activation and SMX degradation. Cycling experiments and comparison of characterization results before and after experiments proved that O-g-C 3 N 4 nanoflakes had superior catalytic and structural stability. This study could provide a high efficient metal-free carbonaceous activator of PMS for the degradation of antibiotics in the wastewater.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Nature Chemistry
·
2024
·Vol. 16
·期 6
·893-900
·
IF 19.2
Zhang Lei,Bai Rui,Lin Jin,Bu Jun,Liu Zhenpeng,An Siying,Wei Zhihong,Zhang Jian
Metal-free catalysts offer a desirable alternative to traditional metal-based electrocatalysts. However, metal-free catalysts, featuring defined active sites, rarely show activities as promising as metal-based materials. Here we report 2-thiolimidazole as an efficient metal-free catalyst for selective electrocatalytic hydrogenation of acetylene into ethylene. Under alkaline conditions, the sulfhydryl and imino groups of 2-thiolimidazole are spontaneously deprotonated into dianions. Deprotonation thus enriches the negative charges of pyridinic N sites in 2-thiolimidazole to enhance the adsorption of electrophilic acetylene through the σ -configuration. Ethylene partial current densities show a volcano relationship with the negative charges of the pyridinic N sites in various imidazole derivatives. Consequently, the deprotonated 2-thiolimidazole exhibits an ethylene partial current density and faradaic efficiency competitive with metal-based catalysts like Cu and Pd. This work highlights the tunability and promising potential of metal-free molecules in electrocatalysis.
研究领域:
电化学
·
催化
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yaoping Guo,Qixing Peng,Yaxiong Huang,Shuai Yan,Yan Luo,Keng Xuan,Huimin Hu,Hao Jiang,Guanghui Wang,Sufen Zhao,Yadan Guo
In-situ S-doped mesoporous carbons (ACS) were fabricated through template method by using sucrose as carbon source and basic magnesium sulfate whisker (513 MOS) as both sulfur source and template. ACS were highly efficient for the activation of peroxydisulfate (PDS) towards aqueous oxytetracycline (OTC) removal. Investigation on the effects of 513 MOS/ sucrose mass ratio on the physicochemical properties and catalytic performance indicated that higher specific surface area, pore volume, thiophene-S (C-S-C) group content as well as carbon skeleton defects contributed to the excellent activity of ACS. 100 % of OTC removal was achieved by ACS-2 within 30 min under the optimal reaction condition, which outperformed most reported transition-metal based and carbon-based heterogeneous catalysts. ACS-2 also showed excellent adaptability with wide pH range as well as various pollutants. Mechanism studies showed that PDS were activated through radical and non-radical pathways, and four plausible degradation pathways of OTC were proposed according to the intermediates identification. This work provides a straightforward method for the construction of metal-free sulfur-doped activated carbons with highly activity for the removal of refractory organic pollutants.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
GREEN CHEMISTRY
·
2017
·Vol. 19
·期 4
·1175-1181
·
IF 9.125
Qingqing Gu,Guodong Wen,Yuxiao Ding,Kuang-Hsu Wu,Chengmeng Chen,Dangsheng Su
Nanocarbons have been extensively used as metal-free alternatives to metal catalysts in many oxidative processes owing to their functional groups or defects, which have the activation ability toward oxygen molecules. Herein, reduced graphene oxide (rGO) could be used as catalysts in oxidative desulfurization reactions for the first time to remove sulfur-containing compounds from fuels. Superior catalytic activity and stability are obtained in the aerobic oxidative desulfurization process catalyzed by rGO. A broad range of sulfur-containing aromatic substrates could be removed effectively in this catalytic system. Carbonyl groups have proved to play crucial roles during the oxidation process based on an XPS analysis, a chemical titration method and a series of comparative experiments. The chemically active defects are also beneficial to the catalytic performance because carbonyl groups could be generated in situ on these defects under the reaction conditions. Based on the EPR results, a radical pathway is proposed. Oxygen molecules could interact with the carbon atoms adjacent to carbonyl groups to form adsorbed super oxygen anion radicals (rGO-OO˙−), which then attack the adjacent sulfur-centered cation radicals and generate the final product sulfone.
研究领域:
纳米碳材料
·
催化化学
·
燃料净化
·
环境催化
·
表面化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）