ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
Aili Liu,Wei Li,Huile Jin,Xiaochun Yu,Yongfeng Bu,Yuhua He,Huihui Huang,Shun Wang,Jichang Wang
Graphene co-doped with fluorine and chlorine heteroatoms was prepared through a one-step synthesis and was investigated as the oxygen reduction electrocatalysts. Voltammetric measurements show that fluorine and chlorine co-doped graphene has remarkable catalytic activity toward the electrochemical reduction of oxygen in alkaline solution. Besides having a high tolerance to methanol crossover effect, the co-doped graphene also showed a better stability than that of commercial Pt/C electrocatalysts and of the chlorine-doped graphene that was prepared by the same approach. The charge transfer resistance of the co-doped graphene was substantially lower than that of the chlorine-doped graphene, suggesting that there may exist a synergistic interaction between fluorine and chlorine dopants. The rapid synthetic method reported here provides an effective approach for future investigation of halogen (co-) doped graphene.
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高影响因子
DESIGNED MONOMERS AND POLYMERS
·
2015
·
IF 2.78
Nian Deng,Xufeng Ni,Zhiquan Shen
Poly (diethyl vinylphosphonate-co-2-chloroethyl methacrylate) (P(DEVP-co-CEMA)) copolymers are synthesized by free radical copolymerization initiated by benzoyl peroxide. The reactivity ratios for the free radical copolymerization of CEMA (M1) and DEVP (M2) are r1 = 19.45 and r2 = 0.11, respectively. The desired amphiphilic copolymers with relatively low polydispersity index (PDI) and different DEVP contents are isolated and purified from the reaction mixtures through precipitation fractionation. The structures and molecular characteristics of the obtained products are characterized by 1H NMR, FTIR, and SEC analysis. All of these fractionated copolymers have a unimodal distribution and moderate PDI. The thermal properties of the P(DEVP-co-CEMA) copolymers are investigated by TGA and differential scanning calorimetry (DSC) measurements. Single glass transition temperature (Tg) appears in the DSC profiles differing from the existence of two Tgs in the blend of poly (diethyl vinylphosphonate) and poly (2-chloroethyl methacrylate), which indicates the random structure of the copolymers. The MALDI–ToF mass analysis further reveals that DEVP and CEMA units are randomly distributed in the copolymer chains. The self-assembly behavior of the P(DEVP-co-CEMA) copolymers in aqueous solution is preliminarily investigated.
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Reaction Kinetics Mechanisms and Catalysis
·
2014
·Vol. 113
·期 1
·281-292
·
IF 0.983
Huang Ji-guo,Zheng Meng-yang,Pang Shuo,Liu Li-guo,Zhao Xiao-guang,Dong Li-li,Liu Xing-juan
N–Si co-doped TiO 2 nanoparticles for the photodegradation of phenol were prepared by SiCl 4 and TiCl 4 co-hydrolysis and the effect of H 2 O 2 modification was studied. The characterization results revealed that the Si doped into the TiO 2 lattice was limited and the redundant silicon existed in segregated amorphous silica. The average crystallite size of the photocatalysts reduced from 14.8 to 5.5 with increasing Si doping ratio. The absorption edges of the as-prepared samples got an obvious red shift in which the best one reached 526 nm. N and Si co-doped into the photocatalysts replaced Ti and formed the Ti–O–Si and O–Ti–N link-ages. The photocatalysts modified by H 2 O 2 were well dispersed and changed the molecular structure. The degradation effect of the used Si doped photocatalysts was better than for undoped photocatalysts, and the H 2 O 2 modification could not further enhance the photocatalytic activity for N–Si doped TiO 2 . For the photodegradation of phenol, the optimal molar ratio of Si/Ti and the calcination temperature was 1:4 and 650 °C, respectively. For the optimal photocatalyst, the molar ratios of O/Ti, N/Ti, and Si/Ti were 0.54, 0.19, 0.29, and the phenol removed 94.4 % in 6 h under solar light. The reusability of N–Si co-doped TiO 2 was relatively good.
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Journal of Materials Chemistry A
·
2014
·Vol. 2
·期 30
·11697-11705
·
IF 0
Akram Alabadi,Xinjia Yang,Zehua Dong,Zhen Li,Bien Tan
Nitrogen-doped activated carbons (N-ACs) with controlled nitrogen doping and analogous microporous structures were prepared by pyrolysis of poly[(pyrrole-2,5-diyl)-co-(benzylidene)] (PPCB). The obtained N-ACs were thoroughly characterized using HRTEM, FESEM, BET, FTIR and XPS for their morphology, surface area and chemical composition. The N-ACs were further used to fabricate supercapacitors, and their comprehensive electrochemical properties, such as cyclic voltammograms, galvanostatic charge–discharge, electrochemical impedance spectrum, electrochemical capacitive performance, power density and long cyclic stability, were studied. The galvanostatic charge–discharge (GC) measurements on N-ACs produced at 700 °C and 800 °C show a high specific capacitance (up to 525.5 F g−1 and an energy density of ca. 262.7 W h kg−1 at 0.26 A g−1) in alkaline media (2 M KOH). More importantly, the capacitance remains practically identical when the scan rate was increased from 0.26 to 26.31 A g−1. The observed capacitance retention (∼99.5%) of N-ACs is remarkably stable for electrodes even after 4000 cycles, due to the presence of nitrogen at the surface and in the graphitic edge planes. The nitrogen content plays a significant role in producing micropore dominated ACs and in facilitating the transfer of ions through pores on the surface. The precursor (PPCB) used is cheap and can easily be prepared, making it promising for the large-scale production of N-ACs as excellent electrode materials for supercapacitors.
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OPTIK
·
2017
·
IF 0.835
Renping Cao,Kailei Bai,Xing Liu,Wudi Wang,Ting Chen,Siling Guo,Zhiyang Luo,Wensheng Li
A series of CaZn 2 P 2 O 8 :Sm 3+ , Mn 2+ phosphors are synthesized by a solid-state reaction method in air. The crystal structures and luminescence properties are investigated. CaZn 2 P 2 O 8 :Sm 3+ phosphor with excitation 402 nm emits red light in the range of 550–750 nm owing to the 4 G 5/2 → ( 6 H 5/2 , 6 H 7/2 , 6 H 9/2 , and 6 H 11/2 ) transitions of Sm 3+ ion. CaZn 2 P 2 O 8 :Mn 2+ phosphor with excitation 400 nm emits yellow-green light in the range of 500–650 nm due to the 4 T 1 (G) → 6 A 1 transition of the Mn 2+ ion. CaZn 2 P 2 O 8 :Sm 3+ , Mn 2+ phosphor with excitation 400 nm shows a tunable emission in the range of 500–750 nm with changing Sm 3+ or Mn 2+ ion content. The optimal Sm 3+ and Mn 2+ ion concentrations are ∼4 mol% and 3 mol%, respectively.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2016
·
IF 3.205
Beibei Yu,Wenqin Wu,Jiayi Jin,Huimin Wu,Shengfu Wang,Qinghua Xia
Co-based selenides with different selenium contents were successfully synthesized by a one-pot solvothermal method . The physical properties of the prepared catalysts were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis . While their electrocatalytic performances were evaluated by cyclic voltammetry , linear sweep voltammetry , electrochemical impedance spectroscopy and chronoamperometry . The results showed that the Co-Se-75 displayed better electrocatalytic activity towards the oxygen reduction reaction with higher onset potential (0.708 V vs. RHE), reduction current (2.81 mA cm −2 ) and a four-electron oxygen reduction process. Furthermore, the catalyst exhibited better stability, stronger resistance to methanol, ethanol and ethlene glycol than that of the Pt/C (20 wt% Pt) catalyst.
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CRYSTENGCOMM
·
2016
·Vol. 18
·期 19
·3498-3505
·
IF 3.849
Jian-Rong Wang,Xiaojuan Wang,Yong Yang,Xiaoyan Chen,Xuefeng Mei
17β-estradiol (E2) is a steroid hormone with low oral bioavailability due to its low aqueous solubility (0.2–5 μg mL−1). To improve its solubility and thus bioavailability, two co-crystals of E2 with isonicotinamide (INA) (1) and piperazine (PIP) (2) were successfully designed and synthesized and their structures were successfully determined. In vivo PK studies revealed that 1 possesses improved bioavailability in an animal model.
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高影响因子
Nano Energy
·
2016
·
IF 11.553
Qingping Wu,Feng Huang,Mingshi Zhao,Ju Xu,Jiangcong Zhou,Yuansheng Wang
Blue TiO 2 (Ti 3+ defected TiO 2 ) nanoparticles have been intensively investigated for photocatalytic H 2 production. However, the Ti 3+ , with energy level ~1.0 eV below the conduction band , cannot initiate visible light driven H 2 production. Thus, Pt or NiO x is often used as a co-catalyst, which is economically unattractive and environmentally contaminative. In this paper, the ultra-small yellow TiO 2 nanoparticles (~3 nm) have been firstly synthesized without introducing any external dopants . The titanium vacancies (acceptor) and titanium interstitials (donor) that incorporated in the yellow TiO 2 are evidenced by various characterization techniques, and their formation mechanism is proposed. Photocatalytic evaluations indicate that the acceptor–donor defects play key roles in the catalytic process, not only initiating, but also promoting the visible light driven H 2 production. The improved activity is also evidenced by that the simulated solar light driven H 2 production for the yellow TiO 2 is ~3.7 fold comparing to that of the normal TiO 2 . A reasonable explanation is that the acceptor-donor defect associates form internal polarization for spontaneously separating photo-generated charge-carriers. The improved charge-carrier separation has been confirmed by photoluminescence spectra and photoluminescence emission decay profiles. Instead of the traditional TiO 2 based photocatalysts , the acceptor–donor defect engineered photocatalyst system offers a new approach for simultaneously initiating and promoting visible light driven co-catalyst free H 2 production.
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MATERIALS RESEARCH BULLETIN
·
2016
·
IF 2.435
Honghong Liu,Hong Gong,Mingming Zou,Heng Jiang,Rasaki Sefiu Abolaji,Ayesha Khan Tareen,Branislav Viliam Hakala,Minghui Yang
Mo-N-co-doped mesoporous TiO 2 microspheres were synthesized via a solvothermal method, followed by nitriding treatment under ammonia gas flow. The efficiency of the samples was investigated by monitoring the degradation of Rhodamine-B under visible light irradiation. The experimental results revealed that Mo-N-co-doped mesoporous TiO 2 microspheres showed better performances than Mo-TiO 2 microspheres. It was observed that; 0.1% molar quantity of Mo doped on TiO 2 at 500 °C for 2 h under nitriding conditions gave highest photocatalytic activities. The nitridation under ammonia gas of Mo-TiO 2 samples created oxygen vacant sites and led to incorporation of substitutional and interstitial Nitrogen. The enhanced visible light photocatalytic activities of Mo-N-co-doped TiO 2 photocatalyst was attributed to the large surface areas, narrow band gap and intense light absorbance in visible region. This study may create a promising and eco-friendly method towards synthesis of metal and non-metals co-doped on semiconductor materials to improve their photocatalytic activities and applications.
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POLYMER
·
2016
·
IF 3.586
Cai Xiaodong,Yang Xiangui,Wang Gongying
Multiblock poly(carbonate-co-esters) (PBC-PBSe) containing poly(butylene carbonates) (PBC) and poly(butylene sebacate) (PBSe) were synthesized successfully via chain-extension of dihydroxyl terminated PBC (PBC-OH) and PBSe (PBSe-OH) using 1,6-hexmethylene diisocyanate (HDI) as chain extender. The chemical structures , molecular weights , crystallization behaviors , thermal, degradation as well as mechanical properties of the copolyesters were characterized by Proton nuclear magnetic resonance spectroscopy ( 1 H NMR), Fourier transform infrared spectroscopy (FT-IR), Gel permeation chromatography (GPC), Differential scanning calorimetry (DSC), Thermogravimetry analysis (TGA), hydrolytic degradation and mechanical testing, respectively. The results indicated that the introduction of PBSe segment not only significantly enhanced the crystallization rate of PBC, but also displayed the same crystallization mechanism within the investigated crystallization temperature range despite of the variation of the PBSe segment content. Furthermore, the thermal stability and hydrolytic degradation rate of PBC-PBSe multiblock copolymers increases with increasing PBSe content. The mechanical properties of copolymers can be adjusted by changing the feed composition .
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CRYSTENGCOMM
·
2017
·Vol. 19
·期 38
·5780-5786
·
IF 3.474
Kun Ding,Xiao Zhang,Juping Li,Ping Yang,Xin Cheng
Ultrathin α-Co(OH)2 nanosheets (NSs) were hydrothermally synthesized without using surfactants and templates. Interestingly, the ultrathin α-Co(OH)2 NSs evolved from graphene-like NSs to hexagonal nanoplates (NPs) and then transformed into a needle-like Co(CO3)0.5(OH)·0.11H2O phase with increasing reaction temperature and time. The phase and morphology evolution depended strongly on the CO32− ions in the solution. We ruled out the possibility that CO32− originated from the adsorption of CO2 in air and proposed the possible phase transition mechanism from α-Co(OH)2 to Co(CO3)0.5(OH)·0.11H2O, which was due to the decomposition of hexamethylenetetramine driven by dynamics and thermodynamics. The morphology evolution could be regarded as the dissolution–recrystallization–redissolution–recrystallization of α-Co(OH)2. The electrochemical behavior tests demonstrated that the ultrathin α-Co(OH)2 electrode exhibited an excellent specific capacitance of 833.4 F g−1 at 5 A g−1; however, the specific capacitance of the needle-like Co(CO3)0.5(OH)·0.11H2O electrode was 247.2 F g−1 at the same current density. This excellent electrochemical property is attributed to the crystalline phase and ultrathin nature of the materials.
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RSC Advances
·
2016
·Vol. 6
·期 41
·34096-34102
·
IF 3.289
Wen-Ze Qiu,Yan Lv,Yong Du,Hao-Cheng Yang,Zhi-Kang Xu
High performance nanofiltration (NF) membranes are facilely fabricated via the co-deposition of catechol (CCh) and polyethylenimine (PEI) on the surface of a polysulfone (PSf) ultrafiltration membrane, with subsequent cross-linking by glutaraldehyde (GA). The surface properties of the studied membranes have been investigated in detail by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning election microscopy, atomic force microscopy, zeta potential, and water contact angle. The NF performance of the membranes are dependent on the CCh/PEI ratio, co-deposition time and cross-linking condition. Results reveal that the optimum membrane yields a rejection of 88% and a permeation flux of 25 L m−2 h−1 when filtrating the 1000 mg L−1 MgCl2 solution at 0.6 MPa. And the negatively charged membrane surface is related to the following salt rejection sequence: MgSO4 > Na2SO4 > MgCl2 > CaCl2 > NaCl. Meanwhile, the membranes show excellent operation stability during a 240 h consistent filtration test.
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