FUEL
·
2021
·
IF 6.609
Dawang Chu,Zhicheng Luo,Yingying Xin,Chengzhen Jiang,Shaofeng Gao,Zhihao Wang,Chen Zhao
The chemo-catalytic production of ethanol from nonedible lignocellulosic biomass is essential for mitigating energy shortage. In this work, we developed a multifunctional Pd-Cu-WO x /SiO 2 catalyst for the one-pot aqueous-phase conversion of cornstalk-derived cellulose to ethanol with a yield of 42.5C% at 300 °C and 4 MPa H 2 . Kinetic studies demonstrated that the transformation of cellulose to ethanol followed a number of consecutive steps namely, cellulose hydrolysis to glucose with H + in hot water (k 1 ), glucose conversion to glycolaldehyde over W species (k 2 ), glycolaldehyde hydrogenation to ethylene glycerol (EG) over Pd (k 3 ), and EG hydrogenolysis to ethanol over Cu (k 4 , rate-determining step). The individual rates were well balanced on Pd, Cu, and WO x species to achieve an ethanol formation rate of 0.163 g·g Cat . −1 h −1 . The addition of Au to Cu-WO x species led to a relatively low k 3 and thus the formation of a substantial amount of humins, while the Ru introduction catalyzed the over-hydrogenolysis of ethanol to methane and ethane with a high rate, thereby lowering the selectivity to ethanol. The characterization results showed that both the electronic properties of Cu + species and the Cu + /Cu 0 ratio on the Pd-Cu-WO x /SiO 2 catalyst contributed to a specific C O bond cleavage, especially for EG hydrogenolysis to ethanol during the cellulose conversion.
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·Vol. 48
·期 10
·14315-14322
·
IF 5.532
Jie Chen,Yixin Gao,Chao Wang,Yu Yin,Jiaxing Song,Xiaodan Zeng,Zhigang Liu,Haifeng Jiang
Upconversion luminescence materials have gained extensive attentions owing to their unique luminescence characteristics of converting near-infrared excitation to visible light emission. However, how to improve the doping concentration of activator (usually <3 mol%) in traditional sensitizer-activator system is still a great challenge due to the luminescence quenching effect. In this work, NaErF 4 crystals with diverse crystal phases and morphologies were prepared by simple hydrothermal method , constructing a 100% doping concentration system of activator (Er 3+ ). With the increase of F − content, the phase of NaErF 4 transfers from cubic to hexagonal, and the morphology changes from nanospheres to hexagonal microflakes, meanwhile, the upconversion luminescence intensity also increases gradually. In addition, in order to further inhibit the luminescence quenching effect of NaErF 4 bare core, a series of NaErF 4 @SiO 2 core-shell samples with different SiO 2 shell thickness were successfully prepared. Compared with NaErF 4 bare core, the morphology and structure of the NaErF 4 @SiO 2 core-shell samples have no obvious change, but the UC luminescence intensity is significantly enhanced. Interestingly, the change of NaErF 4 crystal phase and SiO 2 shell thickness can both bring about multicolor luminescence. In addition, different from the traditional NaYF 4 :Yb, Er co-doping system, the as-prepared hydrophilic NaErF 4 and NaErF 4 @SiO 2 samples showed a greater red to green ratio (R/G > 1), which may expand their potential applications in biological imaging and sensing fields.
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DOI
高影响因子
Analytical Methods
·
2014
·Vol. 6
·期 12
·4102-4106
·
IF 1.938
Tianyu Yao,Qin Tu,Xiang Han,Longlong Zhang,Dong-En Wang,Manlin Li,Sheng Chen,Jinyi Wang
Based on the formation of a red [Cd-diphenylcarbazide] complex, a simple and visible method for Cd2+ colorimetric detection was developed by doping SiO2 nanoparticles and diphenylcarbazide in polymethylmethacrylate electrospun fibers. Benefiting from the large surface area due to the addition of SiO2 nanoparticles, the color of the fibrous film changed clearly even in the presence of extremely low concentrations of Cd2+. The detection limit was found to be 1 × 10−8 M. Investigation of the selectivity of the fibrous film on the detection of various metal ions showed that only Cd2+ could induce a yellow-to-red color change. The results demonstrated that SiO2 and diphenylcarbazide doped polymethylmethacrylate fibrous films could act as highly selective strips for the detection of Cd2+ with little interference from other metal ions.
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DOI
高影响因子
ADVANCED POWDER TECHNOLOGY
·
2020
·Vol. 31
·期 9
·3910-3920
·
IF 4.217
Hui Pan,Shuxia Wang,Xiaodong Wang,Chunhong Gong,Tao Ding
The near-spherical silica nanoparticles with polyvinyl alcohol (denoted as PVA-SiO 2 ) or polyethylene glycol (denoted as PEG-SiO 2 ) as surface modifiers were loaded onto graphene oxide nanosheets (denoted as GO) to prepare PVA(PEG)-SiO 2 -GO nanocomposites. The nanocomposites well dispersed in water were then compounded with maleic anhydride (MA) - acrylic acid (AA) copolymer (denoted as PMAAA) to prepare new nanocomposite tanning agents (denoted as PVA(PEG)-SiO 2 -GO/PMAAA). The hydrothermal stability, thickness increase, mechanical properties, flame retardancy and antistatic property, etc. of the leather tanned with PVA(PEG)-SiO 2 -GO/PMAAA were founded to be improved in a significant way compared with those of the leather tanned with the commercial acrylic resin (CHINATAN OM) and pure PMAAA copolymer tanning agents. The acquired excellent tanning properties may be related to the synergistic tanning effects of near-spherical silica nanoparticles and thin-layered graphene oxide nanosheets in leather tanning process. Especially, the highest shrinkage temperature of the wet-white sheepskin tanned with PVA-SiO 2 -GO/PMAAA reached 71 ◦ C and the thickness increase reached 190% without chrome tanning agents.
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DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 33
·25959-25966
·
IF 3.84
Minhua Zhang,Meixiang Gao,Jianyue Chen,Yingzhe Yu
The structure and surface properties of the MgO/SiO2 catalyst were studied by both experimental characterization and the simulation method. The adsorption properties of ethanol on different MgO/SiO2 surfaces were researched by the density functional theory method and the result is that ethanol mainly adsorbed on MgO surface. The role of SiO2 in increasing the MgO crystal defects in the MgO/SiO2 has been obtained and the electronic properties of ethanol molecule before and after adsorption on the catalyst surfaces were compared. The initial step of ethanol dehydrogenation and the dehydration to 1,3-butadiene process, which is the dehydrogenation of ethanol to acetaldehyde reaction, on the flat sites, stepped sites and kinked sites was examined through the molecular simulation method. We investigated the preferable surface for the reaction of ethanol dissociation to an ethoxy group and the more active surface for the reaction of dehydrogenation of ethanol to acetaldehyde. The research results suggested that the stepped MgO surface is more active for the reaction of dehydrogenation of ethanol to acetaldehyde.
研究领域:
催化化学
·
计算化学
·
表面科学
·
材料化学
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DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2020
·Vol. 104
·期 2
·824-832
·
IF 3.502
Dashuang Ding,Yanlong Wang,Changgui Lin,Jing Ren,Wenbo Shi,Pengyuan Wang,Bing Yang,Shaoqian Zhang,Liping Duo
Incorporation of transition-metal ions (TMIs) in the precipitated nanocrystals (NCs) of glass-ceramics (GCs) greatly improves the photonic properties of these materials. The crystal field and coordination of TMIs show fingerprints for spectroscopic characterization. However, it is difficult to probe the effect of the host NCs’ structural phase on doped TMIs’ d-d orbitals. Herein, ZnF 2 :Ni and KZnF 3 :Ni based on controllable crystallization in KF-ZnF 2 -SiO 2 :Ni 2+ GCs were taken as model systems. Compared to ZnF 2 , perovskite-type KZnF 3 has higher binding energy Zn-F bonds in which Ni 2+ are easier to be segregated, which makes KZnF 3 :Ni be better “excited electron trapper” due to hole localization to intra-gap Ni states. These findings contribute to the understanding and design of TMIs-doped GCs in practical applications.
研究领域:
材料科学
·
光子学
·
固态化学
·
纳米材料
·
光学材料
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DOI
高影响因子
WEAR
·
2026
·
IF 6.1
Dapeng Gu,Hao Xu,Ke Liu,Chenxi Suo,Junqi Ge,Suwen Chen
To achieve the low-temperature combination of ceramics and polymers, the core-shell structure and cold sintering method are employed to prepare ceramic/polymer composites. An easy-bonding Silica (SiO 2 ) shell was introduced onto the surface of the hard-bonding Hexagonal boron nitride (h-BN) core by a sol-gel method to fabricate a core-shell structured h-BN@SiO 2 composite. Polyether ether ketone (PEEK) was subsequently filled into h-BN@SiO 2 to prepare h-BN@SiO 2 /PEEK ceramic composite by a cold sintering method. The effects of PEEK content (20 vol%, 35 vol%, and 50 vol%), sintering temperature (205 °C, 245 °C, 285 °C, and 325 °C), and molding pressure (350 MPa, 450 MPa, and 550 MPa) on the dry tribological properties of h-BN@SiO 2 /PEEK ceramic composites against GCr15 bearing steel were investigated using a ball-on-disc contact configuration. Field emission transmission electron microscopy (TEM), Energy dispersive spectrometer (EDS), Field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectrometer (FTIR) were used to characterize and analyze h-BN@SiO 2 or h-BN@SiO 2 /PEEK ceramic composites. The results indicate that h-BN@SiO 2 /PEEK composite exhibits better tribological performance when fabricated with a PEEK content of 35 vol%, a sintering temperature of 285 °C, and a molding pressure of 450 MPa under the investigated conditions. The formation of a stable and continuous mixed lubrication layer composed of h-BN, PEEK, and SiO 2 is identified as the primary factor contributing to the enhanced friction reduction and wear resistance. Under the investigated conditions, the main wear mechanisms observed in h-BN@SiO 2 /PEEK composites are adhesive wear, fatigue wear, and slight abrasive wear.
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产品关联
DOI
高影响因子
CARBON
·
2023
·
IF 10.9
Dong Sui,Min Yao,Linqi Si,Kun Yan,Jingge Shi,Jianshe Wang,Charles Chunbao Xu,Yongsheng Zhang
Silica (SiO 2 ) is regarded as a promising anode for lithium-ion batteries due to the high specific capacity, abundant resources and low cost. However, the inherently poor electrical conductivity and the huge volume variation during charge/discharge process significantly hinder the application of SiO 2 . Designing nanostructured SiO 2 and coating with high conductivity materials are effective methods to solve the above challenges. In this work, advanced SiO 2 anodes were prepared by coating hollow SiO 2 nanotubes (SNTs) with lignin or phenolated and depolymerized lignin furfural resin (PDLF)-derived carbon. The novel structure of the obtained SNTs greatly promotes the rapid transport for both Li + and electron, increases the exposed active sites for Li + insertion and accommodates the volume change of SNTs. Especially, PDLF possesses abundant functional groups, high carbon content and thermosetting property, which are beneficial to the dispersion of SNTs and formation of a cross-linked 3D conductive network. Thereby, SNTs@C-PDLF presents higher specific capacity of 661 mAh g −1 at 100 mA g −1 , superior rate capability (262 mAh g −1 at 3000 mA g −1 ) and better cycling stability (549 mAh g −1 at 1000 mA g −1 after 800 cycles) compared with SNTs@C-lignin and pristine SNTs.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
功能材料
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DOI
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2025
·
IF 5.4
Jiawen Shang,Fu Qin,Xinyu Wang,Xiaoyue Wang,Xu Yu,Shengyu Qian,Lili Ren
The hydrophilicity and high cost fabrication of aerogels have limited their applications in oil-water separation. Herein, we prepared a novel SiO 2 aerogel using a simple atmospheric pressure drying method and surface silylation modification, with methyl trimethoxy silane (MTMS) and tetraethyl orthosilicate (TEOS) as co-precursors. The experimental results demonstrated that enhancing the degree of methyl group substitution during surface silylation significantly influenced the structure and hydrophobic properties of the SiO 2 aerogel. As the methylation level increased, the bulk density exhibited a notable reduction from 0.216 to 0.094 g·cm −3 , the water contact angle increased from 140° to 152°, porosity rose from 90.18 % to 95.72 %, and particle size gradually reduced. The TMCS-modified SiO 2 aerogel exhibited excellent adsorption rates for soybean oil, dichloromethane, n-hexane, and vacuum pump oil, and has certain separation effect for oil-water emulsion. It still maintained good hydrophobicity under various pH conditions and intact after over 20 adsorption cycles of n-hexane and dichloromethane. We believe that this superhydrophobic and low- cost oil-absorption material has great potential in the actual treatment of oil spill pollution.
研究领域:
材料科学
·
环境工程
·
化学工程
·
纳米技术
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产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Yifei Ye,Lin Liang,Xiao Zhang,Jianmin Sun
In this paper, a novel arginine-glucose derived carbonaceous-material-loaded SiO 2 composite catalyst (Ar-G-CM/SiO 2 ) was synthesized from non-toxic and harmless reagents (arginine, glucose and tetraethylorthosilicate) by simple hydrothermal process. Mesoporous SiO 2 with high specific area served as support for carbonaceous material and provided extra hydrogen bond donor (HBD) groups. Ar-G-CM/SiO 2 with acid-base dual functional groups ( COOH, NH 2 ) and HBD group ( OH) presented 62% yield and 99% selectivity to product of propylene carbonate in CO 2 cycloaddition reaction with propylene oxide even at 40 °C, 2 MPa under metal-absent and solvent-free conditions. For some less active epoxides with steric hindrance, Ar-G-CM/SiO 2 also showed good yield and selectivity over 90% by raising temperature to 120 °C. Furthermore, the Ar-G-CM/SiO 2 catalyst could be reused for six successive cycles without significant decrease in catalytic activity or structural deterioration, because the carbon deposition was restrained owing to the mesoporous structure of the catalyst.
研究领域:
催化化学
·
材料科学
·
环境科学
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DOI
PubMed
高影响因子
VACUUM
·
2021
·
IF 3.627
Wanzhe Tong,Dong Fang,Chongxi Bao,Songlin Tan,Yichun Liu,Fengxian Li,Xin You,Jingmei Tao,Rui Bao,Caiju Li,Jianhong Yi
Silica/Cu composites generally fail to achieve the high strength due to the weak interfacial bonding between SiO 2 and Cu. In the current work, the first use of silica quantum dots (SiO 2 QDs) as a copper-based composite reinforcement. Silicon quantum dots (Si QDs) and copper acetate are employed as raw materials for spray pyrolysis to obtain an interconnected structure of SiO 2 QDs/Cu 2 O, which achieve well-dispersion of the reinforcement and good interface combination in one step. The SiO 2 QDs/Cu 2 O composite block is obtained by ball milling, hydrogen reduction, and SPS sintering. Micro interface structure and strengthening mechanism of the composites are investigated and presented in detail. Microstructural analysis discovers the Cu 2 O transition layer between SiO 2 QDs and Cu matrix and well-dispersed SiO 2 QDs in the Cu matrix. The good bonding of grain interface can significantly enhance the mechanical properties . The 1.2 wt% SiO 2 QDs/Cu composite block exhibits an excellent ultimate tensile strength of 456.63 MPa, which is 101.68% higher than that of unreinforced Cu (227.39 MPa). Furthermore, the composite block maintains the high conductivity (83.27% IACS) and elongation (8.86%). Moreover, this work can promote the development of Cu matrix composites using ceramic reinforcement with an improved interface bonding.
研究领域:
材料科学
·
纳米技术
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DOI
高影响因子
Catalysts
·
2019
·Vol. 9
·期 5
·410
·
IF 3.444
Lei Ma,Shiyan Yuan,Taotao Jiang,Xiangming Zhu,Chunshan Lu,Xiaonian Li
Sulfur species (e.g., H2S or SO2) are the natural enemies of most metal catalysts, especially palladium catalysts. The previously reported methods of improving sulfur-tolerance were to effectively defer the deactivation of palladium catalysts, but could not prevent PdO and carrier interaction between sulfur species. In this report, novel sulfur-tolerant SiO2supported Pd4S catalysts (5 wt. % Pd loading) were prepared by H2S–H2aqueous bubble method and applied to catalytic complete oxidation of methane. The catalysts were characterization by X-ray diffraction, Transmission electron microscopy, X-ray photoelectron Spectroscopy, temperature-programmed oxidation, and temperature-programmed desorption techniques under identical conditions. The structural characterization revealed that Pd4S and metallic Pd0were found on the surface of freshly prepared catalysts. However, Pd4S remained stable while most of metallic Pd0was converted to PdO during the oxidation reaction. When coexisting with PdO, Pd4S not only protected PdO from sulfur poisoning, but also determined the catalytic activity. Moreover, the content of Pd4S could be adjusted by changing H2S concentration of H2S–H2mixture. When H2S concentration was 7 %, the Pd4S/SiO2catalyst was effective in converting 96% of methane at the 400 °C and also exhibited long-term stability in the presence of 200 ppm H2S. A Pd4S/SiO2catalyst that possesses excellent sulfur-tolerance, oxidation stability, and catalytic activity has been developed for catalytic complete oxidation of methane.
研究领域:
催化化学
·
环境催化
·
材料化学
·
能源化学
·
表面科学
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DOI
高影响因子
危险品化学品经营许可证（带存储）