MACROMOLECULES
·
2019
·
IF 5.997
Ningwei Sun,Kaixin Su,Ziwei Zhou,Xuzhou Tian,Zhao Jianhua,Danming Chao,Daming Wang,Franziska Lissel,Xiaogang Zhao,Chunhai Chen
Electrofluorochromic (EFC) materials have aroused great interest owing to their interesting ability of tuning fluorescence in response to the applied potential. However, some crucial characteristics, such as response speed, fluorescence contrast, and switching stability, are still not well realized to meet the requirements of practical applications. Herein, we designed and synthesized a novel polyamide-bearing aggregation-induced emission (AIE)-active tetraphenylethylene (TPE) and a highly conjugated triphenylamine (TPA) pendant group. The rational combination of the highly conjugated TPA and TPE caused the resultant polymer to exhibit highly integrated electrochromic (EC) and EFC performances including multiple color-changing (colorless to green to blue), fast response speed (1.8/1.1 s for EC and 0.4/2.9 s for EFC process), high fluorescence contrast (82 at the duration time of 20 s), and excellent long-term stability over 300 cycles. The strategy of AIE functionality by combing a highly conjugated redox unit demonstrates a synergistic effect to prepare high-performance emission/color dual-switchable materials, greatly promoting their applications in sensors, smart windows, and displays.
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2020
·Vol. 12
·期 5
·3469-3481
·
IF 6.895
Longfei Guo,Fuyi Chen,Tao Jin,Huazhen Liu,Nan Zhang,Yachao Jin,Qiao Wang,Quan Tang,Bowei Pan
Formate is a kind of carbon-neutral fuel that can be synthesized by electrochemical conversion of CO2, however, the generated aqueous formate electrolyte is still short of potential application. Here, formate solution is proposed to be utilized as anode fuels of direct formate fuel cells through the formate oxidation reaction (FOR), and graphene supported AgPd nanoalloys (AgPd/rGO) are prepared to catalyze the FOR. Specifically, the mass activity of the as-prepared Ag49Pd51/rGO catalyst is 4.21 A mg−1Pd and the retention activity of Ag49Pd51/rGO is 49.1% of initial activity after successive 500 cycles, which is 2.48 and 3.03 times higher than that of unsupported Ag51Pd49 nanoalloys. When increasing the positive scan limit from 0.0 to 0.8 V, the mass activity of the Ag49Pd51/rGO catalyst increases from 2.32 to 6.03 A mg−1Pd and Pd surface coverage increases from 51.87% to 62.42%, indicating the occurrence of surface reconstruction where Pd atoms migrate to the surface of AgPd nanoalloys, and less intensive reconstruction is observed in unsupported Ag51Pd49 nanoalloys, whose mass activity increases from 1.35 to 2.49 A mg−1Pd. The driving force and kinetic path are calculated for the surface reconstruction induced by the adsorption of H, O and C atoms, in the case of C atoms on graphene, the segregation energy of surface Pd atoms in the AgPd nanoalloy is −1.16 eV, and the activation energy for the migration of subsurface Pd atoms to the surface is 0.54 eV, which are lower than the segregation (0.03 eV) and activation (2.06 eV) energy on a clean alloy surface.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
GREEN CHEMISTRY
·
2019
·Vol. 21
·期 23
·6326-6334
·
IF 9.405
Shengxiang Qin,Teng Li,Man Zhang,Hongyu Liu,Xin Yang,Nianxin Rong,Jun Jiang,Yalin Wang,Hua Zhang,Weiran Yang
Production of biodiesel from biomass resources usually requires elongation of carbon numbers from typical C5 and C6 platform molecules through C–C coupling reactions, which were catalyzed by acid, base or metal catalysts traditionally. Herein, a catalyst-free method was developed to produce bis(furan-2-yl)methane derivatives (BFMs) from furfuryl alcohol derivatives (FAs) in the presence of H2O and air without any other additional catalysts. An 81% yield of bis(5-methylfuran-2-yl)methane (BMFM) can be obtained from 5-methylfurfuryl alcohol (5-MFA) and a 59% total yield of C11 biodiesel was obtained from 5-methylfurfural (5-MF). In addition, a H2O and air mediated free radical decarboxylation mechanism was proposed based on the detailed mechanistic studies. This strategy offers a green, low-cost and environmentally friendly approach to synthesize biodiesel precursors from biomass based platform molecules.
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2019
·Vol. 12
·期 3
·2126-2132
·
IF 6.97
Hui Xu,Hongyuan Shang,Cheng Wang,Liujun Jin,Chunyan Chen,Yukou Du
Although great successes have been accomplished on the controlled synthesis of 2D and 3D Pd-containing nanomaterials, tapping into the novel Pd-containing electrocatalysts that combined the advantages of both 2D and 3D structures remains a significant challenge. Here, an approach to systematically produce porous Fe-doped Pd nanosheet assemblies (NSAs) with a geometry tuning from PdFe hollow nanospheres (HNSs), PdFe nanocages (NCs), to PdFe nanoplates (NPs) is reported. The inherent ultrathin and porous features endow these PdFe catalysts with excellent electrocatalytic performance. As a result, the optimized 3D PdFe NCs show a much-improved methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR) activities in comparison with PdFe HNSs, Pd NPs, and commercial Pd/C catalysts. Moreover, these PdFe nanocatalysts also display greatly enhanced electrocatalytic stability, which can endure 500 cycles with negligible activity loss and structural changes. The mechanism investigations reveal that the introduced Fe atom efficiently modulates the electronic structure of Pd, leading to the downshift of the d-band center of Pd, which is beneficial for the adsorption of reactants. Moreover, the porous nanosheet assembly structure can provide rich mass and electron transfer channels, further boosting the improvement of electrocatalytic performance.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CATALYSIS
·
2019
·
IF 7.723
Zhaolin He,Jin Liu,Qijun Wang,Meng Zhao,Zhipan Wen,Jun Chen,Devaraj Manoj,Chuyi Xie,Jiangbo Xi,Junxia Yu,Chunyan Tang,Zhengwu Bai,Shuai Wang
Eco-friendly carbocatalyst is extremely desirable in organic catalysis and wastewater treatment. Herein, we reported a one-pot synchronous hydrothermal process to synthesize a highly efficient N doped holey graphene (NHG) carbocatalyst, in which graphene oxide nanosheets are self-assembled, reduced, chemically etched, and simultaneously doped with nitrogen to form a graphene hydrogel in the presence of H 2 O 2 and NH 4 OH. Benefiting from the good hydrophilicity, unique hierarchical porous structure, large specific surface area (322.1 m 2 g −1 ), and high N content (9.77 at. %), the resultant NHG carbocatalyst exhibits an excellent catalytic performance for the hydrogenation of N-containing unsaturated compounds. In 4-nitrophenol reduction reaction, the NHG carbocatalyst delivers a turnover frequency of 3.32 × 10 −2 min −1 . This catalytic activity is superior to that of the commercial Pd/C (5.0 wt%), other previously reported carbocatalysts, and many noble-metal-based catalysts. Furthermore, the molecular structure analysis combined with density functional theory calculations elucidate metal-free catalytic mechanism of hydrogenation reaction for unsaturated chromophore groups in N-containing organic dyes.
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2019
·
IF 3.021
Bingxing Jiang,Jun Hu,Yiheng Qiao,Xiaoxiang Jiang,Ping Lu
Performance of Ni–Pd bimetallic catalysts on depolymerization of lignin into monomeric phenols was investigated using isoproponal as an in situ hydrogen source. The performance of catalysts and the effects of temperature and starting lignins were extensively examined. Ni50Pd50/SBA-15 exhibited the best performance in the depolymerization of cellulolytic enzyme corn stalk lignin, affording the highest total monophenols yield of 8.14 wt % which was 1.96 times that of Ni/SBA-15 and 1.44 times that of Pd/SBA-15. For the depolymerization of acid-extracted birch lignin, 18.52 wt % monophenols were obtained over Ni50Pd50/SBA-15 at 245 °C for 8 h, and 4-propylsyringol had 8.89 wt % yield with 47.97% selectivity. The physicochemical characteristics of the catalysts were elucidated with ascanning electron microscopy, high-resolution transmission electron microscopy, nitrogen adsorption/desorption, X-ray diffraction, and X-ray photoelectron spectroscopy. The bimetallic catalyst had the characteristics of narrow distribution of metal particles with a small size, well-retained hexagonal pore structure of SBA-15, higher dispersion of Pd, and more Pd0 and Ni0 as compared with monometallic catalysts. The properties of the bimetallic catalyst provide more contact opportunities between the abundant active centers and lignin fragments, and therefore significantly promote the hydrogenolysis process to produce monomeric phenols.
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2018
·
IF 3.024
Da Wang,Yuyang Wang,Xiaoyu Li,Lei Chen,Guangci Li,Xuebing Li
In situ catalytic hydrogenolysis of lignin is an efficient method for lignin valorization. Herein, a novel in situ lignin catalytic hydrogenolysis technique in alkaline aqueous solution over a NiAl alloy catalyst under mild conditions was systematically suited. Ni served as the active phase and could be exposed by etching Al atoms with alkaline aqueous solution. Meanwhile, H2 resources could be in situ generated and easily arrived at the adjacent exposed Ni sites to be activated. The in situ lignin hydrogenolysis system exhibits attractive depolymerization results under mild conditions, with an 86.8% conversion degree and 18.9 wt % yield of aromatic monomers at 220 °C, much higher than the traditional hydrogenolysis method using a commercial Raney Ni catalyst under high pressure external H2. The mechanism studies with lignin model compounds suggest that alkaline aqueous solution could promote the cleavage of C–O–C bonds and hinder the hydrogenation of the benzene ring. In addition, a moderate amount of exposed Ni sites as well as rich active hydrogen species are determinant for efficient lignin depolymerization.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2018
·Vol. 93
·期 10
·3028-3034
·
IF 2.587
Wei Chen,Yong Sun,Juan Du,Zhihao Si,Xing Tang,Xianhai Zeng,Lu Lin,Shijie Liu,Tingzhou Lei
BACKGROUND 5-(Aminomethyl)-2-furanmethanol (AMF), used widely in medicinal chemistry, is usually synthesized by the reductive amination of furfural or 5-hydroxymethylfurfural (HMF) with ammonia. However, a challenging task when synthesizing this furyl primary amine is to enhance the selectivity of the product due to its high nucleophilicity. Conventional measures have used excessive liquid ammonia and precious metal catalysts. Usually, the molar ratio of ammonia to substrate is up to 30:1. This study employed aqueous ammonia to synthesize AMF by the direct reductive amination of HMF using the non-noble metal Ni/SBA-15 catalyst. RESULTS The Ni/SBA-15 catalyst displayed higher catalytic selectivity in the reductive amination of HMF to AMF compared to other precious metal catalysts, such as Ru/C, Pd/C and Pt/C. The AMF yield of 89.8% was obtained at the relatively mild reaction temperature of 100 °C for 4 h. After the fifth cycle, an acceptable decrease in catalytic activity with 74.2% yield of AMF was observed. CONCLUSION An improved process was developed for preparing AMF by the reductive amination of HMF with aqueous ammonia using the non-noble Ni/SBA-15 catalyst. The high selectivity of nickel catalyst is attributed mainly to the moderate catalytic activity. Moreover, a small amount of water enhanced the yield of AMF by promoting the formation of ammonium ions to prevent the further side reaction of AMF with HMF. Results of recycling experiments and analyses showed that agglomeration, loss and oxidization of nickel species together with carbon deposition were responsible for the slight deactivation of the catalyst. © 2018 Society of Chemical Industry
✓ 已验证
产品关联
DOI
高影响因子
HIGH PERFORMANCE POLYMERS
·
2019
·
IF 1.584
Xianfeng Que,Zhiming Qiu,Yurong Yan
Benzocyclobutene (BCB) resins have aroused much interest because of their excellent physical and chemical properties. Unfortunately the temperature required to induce cross-linking in typical BCBs is higher than 250°C, which restricts their applications. In this study, a novel cyano-containing BCB-terminated imide monomer was synthesized through the reaction of 1-cyano-5-amino-benzocyclobutene with 4,4′-oxydiphthalic anhydride. This monomer allows a 50–100°C lower curing temperature in comparison with typical BCBs, and it is highly soluble in various solvents and can easily convert to cured film at 150–200°C. Because of the presence of rigid imide group and strong polar cyano group, the cured film exhibits excellent mechanical strength with tensile strength up to 87.8 MPa, high glass transition temperature up to 350°C, low coefficient of thermal expansion (36.9 ppm K−1), and outstanding planarity with the average surface roughness as low as 0.26 nm.
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2018
·
IF 3.956
Lele Jin,Wenzhi Li,Qiying Liu,Jindong Wang,Yuanshuai Zhu,Zhenhang Xu,Xiangqian Wei,Qi Zhang
A catalytic routine was developed for kraft lignin depolymerization in dioxane-water systems, in which the catalyst HTaMoO 6 with strong Bronsted acidity and a hydrogenation catalyst (Rh/C) were employed simultaneously. The performance of the composite catalysts was tested in a series of experiments with various reaction temperatures, reaction time and catalyst ratios. Under the optimized conditions, a higher petroleum ether soluble fraction yield of 58.7% was obtained at 320 °C for 24 h. Besides, a higher liquid product yield of 95.6% was achieved at 290 °C for 2 h. Specially, the main compositions of the petroleum ether soluble fraction are monomers and dimers, which can be used as liquid fuel. These results demonstrated that the composite catalyst HTaMoO 6 -Rh/C can effectively catalyze the depolymerization of the kraft lignin into small molecule liquid fuel components.
✓ 已验证
产品关联
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2018
·
IF 2.975
Rui Zhang,Tianyun Li,Houbo Zhou,Huahua Huang,Yongming Chen
Here, we develope a kind of biobased transparent polyimides (PIs) with excellent solubility and mechanical properties by using myo-inositol derived diamines. Two biobased diamines M1 and M2 were synthesized through a protection reaction of –OH units of myo-inositol followed by the substitution and subsequent reduction reactions. Myo-inositol based PIs were prepared via the microwave-assisted polymerization of biobased diamines and commercial dianhydrides. These PIs were soluble in various common solvents even in CH 2 Cl 2 and acetone at room temperature . The biobased PIs also showed good optical transparency with T 450nm values of over 82%. Moreover, all the PI films possessed outstanding mechanical properties with tensile modulus of over 3.5 GPa, which was higher than that of most of petroleum-based PIs. In addition, the PI films containing –OH units were obtained via a simple deprotection reaction of myo-inositol based PIs.
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2018
·
IF 3.849
Lisha Zhao,Xinping Ouyang,Guanfeng Ma,Yong Qian,Xueqing Qiu,Tao Ruan
Alkali lignin (AL) was depolymerized by hydrogenation using Pd/C as the catalyst and formic acid as the hydrogen donor, and the antioxidant activity of hydrogenolysis products of alkali lignin (HPAL) was investigated. It was found that when the degree of depolymerization (DD) was 85.0%, the IC 50 of HPAL reached 25.2 ± 0.9 mg L −1 in terms of the DPPH radical scavenging activity, which was better than both AL (63.5 ± 0.6 mg L −1 ) and commercial antioxidant BHT (38.7 ± 1.0 mg L −1 ). There was a tight relationship between DD and antioxidant activity, indicating that a lower molecular weight of HPAL was beneficial for improving the antioxidant activity. The hydrogenolysis of lignin contributed to an obvious increase of phenolic hydroxyl content which was the essential for antioxidant activity, and hence hydrogenolysis improved the antioxidant activity of HPAL although the methoxyl content decreased slightly. In addition, phenolic structures with para -alkyl had higher antioxidant activity than those without alkyl substituent. However, the antioxidant activity of the phenolic compounds gradually decreased with an increase of the alkyl chain in para -position due to its lower solubility in a polar solvent. The significant improvement of antioxidant activity of lignin after hydrogenolysis may provide a promising approach to high valued utilization of lignin.
✓ 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）