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Gold modified cobalt-based Fischer-Tropsch catalysts for conversion of synthesis gas to liquid fuels

Alan J. McCue, Jura Aponaviciute, Richard P.K. Wells, James A. Anderson

《化学科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 262-269 doi: 10.1007/s11705-013-1334-5

摘要: The addition of Au as a promoter/modifier for alumina supported Co catalyst has been studied by combined high temperature, high pressure Fourier transform infrared (FTIR) and on-line gas chromatography. The combination of these tools permitted the state of the active catalyst surface to be monitored while following the elution of reaction products during the first 5–7 h on stream of the catalyst. The catalysts under study were a 10%Co/Al O and a 2.5%Au/10%Co/Al O Samples were characterised before use using Raman and temperature programmed reduction (TPR). During the initial stages of reaction, hydrocarbons were built up on the surface of the catalyst as monitored by FTIR and the nature and amount of these species were assessed in terms of CH /CH ratio and the density of these alkyl fragments by employing absorption coefficients for the individual components. The nature and reducibility of the Co particles were modified by the presence of Au while the later also shifted the CO/H balance by acting as an effective water-gas shift catalyst during the early stages of reaction. This characteristic was lost during reaction as a consequence of redistribution of the two metallic phases.

关键词: gold modified catalyst     conversion of synthesis gas    

Gold modified microelectrode for direct tetracycline detection

Hongtao WANG, Huimin ZHAO, Xie QUAN

《环境科学与工程前沿(英文)》 2012年 第6卷 第3期   页码 313-319 doi: 10.1007/s11783-011-0323-5

摘要: The residues of tetracycline antibiotics in water have attracted many concerns due to their harmful impact to human health. This paper reports an electrochemical sensor for the determination of tetracycline (TC) by the microelectrode, which was fabricated by electrodeposited gold colloids on tungsten tip. Cyclic voltammerty was used to study the electrochemical behavior of TC on the microelectrode. Well anodic wave was obtained at about 1.5 V in acidic solutions. Electrochemical determination of tetracycline was investigated using microelectrode by cyclic voltammetry. Under optimized conditions, the calibration curves for TC were obtained. The oxidation peak currents were linearly related to TC concentrations in the range of 1–10 mg·L and 10–100 mg·L , respectively. The detection limit was 0.09 mg·L ( / = 3).

关键词: microelectrode     tungsten tip     gold colloids     tetracycline    

Synthesis of boron modified CoMo/Al

Hui Shang, Chong Guo, Pengfei Ye, Wenhui Zhang

《化学科学与工程前沿(英文)》 2021年 第15卷 第5期   页码 1088-1098 doi: 10.1007/s11705-020-1969-y

摘要: Catalytic hydrodesulfurization (HDS) technique is widely used for clean gasoline production. However, traditional HDS catalyst (CoMo/ -Al O ) exhibits high hydrogenation performance of olefins (HYDO), resulting in the loss of gasoline octane number. To achieve high HDS/HYDO ratio, the key issue is to reduce the interaction between active metals and the support, therefore, in this research, the modified CoMo/ -Al O catalysts with various boron amounts were investigated under traditional or microwave heating. The effects of preparing methods as well as boron amounts on the active phase, acidic properties and HDS catalytic activities were examined. Results show that the modification, especially under microwave treatment, can significantly weaken the interaction between the active component and the support by enlarging the surface area and pore diameter, and reducing the acidity of the support. As a result, the stacking numbers of MoS slabs were obviously improved by the modification and microwave treatment, contributing to higher edge/rim ratio, and resulting in higher HDS performance and selectivity to olefin.

关键词: CoMo catalyst     boron modification     surface acidity     microwave heating     selective hydrodesulfurization    

Nanostructured gold films exhibiting almost complete absorption of light at visible wavelengths

Hanbin Zheng, Christine Picard, Serge Ravaine

《化学科学与工程前沿(英文)》 2018年 第12卷 第2期   页码 247-251 doi: 10.1007/s11705-018-1710-2

摘要: Nanostructured metal surfaces have been known to exhibit properties that deviate from that of the bulk material. By simply modifying the texture of a metal surface, various unique optical properties can be observed. In this paper, we present a simple two step electrochemical process combining electrodeposition and anodization to generate black gold surfaces. This process is simple, versatile and up-scalable for the production of large surfaces. The black gold films have remarkable optical behavior as they absorb more than 93% of incident light over the entire visible spectrum and also exhibit no specular reflectance. A careful analysis by scanning electron microscopy reveals that these unique optical properties are due to their randomly rough surface, as they consist in a forest of dendritic microstructures with a nanoscale roughness. This new type of black films can be fabricated to a large variety of substrates, turning them to super absorbers with potential applications in photovoltaic solar cells or highly sensitive detectors and so on.

关键词: nanostructuration     light absorption     coating     gold     electrodeposition     anodization    

Steam reforming of toluene as a tar model compound with modified nickel-based catalyst

Omeralfaroug KHALIFA, Mingxin XU, Rongjun ZHANG, Tahir IQBAL, Mingfeng LI, Qiang LU

《能源前沿(英文)》 2022年 第16卷 第3期   页码 492-501 doi: 10.1007/s11708-021-0721-8

摘要: Catalytic steam reforming is a promising route for tar conversion to high energy syngas in the process of biomass gasification. However, the catalyst deactivation caused by the deposition of residual carbon is still a major challenge. In this paper, a modified Ni-based Ni-Co/Al O -CaO (Ni-Co/AC) catalyst and a conventional Ni/Al O (Ni/A) catalyst were prepared and tested for tar catalytic removal in which toluene was selected as the model component. Experiments were conducted to reveal the influences of the reaction temperature and the ratio between steam to carbon on the toluene conversion and the hydrogen yield. The physicochemical properties of the modified Ni-based catalyst were determined by a series of characterization methods. The results indicated that the Ni-Co alloy was determined over the Ni-Co/AC catalyst. The doping of CaO and the presence of Ni-Co alloy promoted the performance of toluene catalytic dissociation over Ni-Co/AC catalyst compared with that over Ni/A catalyst. After testing in steam for 40 h, the carbon conversion over Ni-Co/AC maintained above 86% and its resistance to carbon deposition was superior to Ni/A catalyst.

关键词: catalytic steam reforming     tar model compound     Ni-based catalyst     carbon resistance    

A Pt-Bi bimetallic nanoparticle catalyst for direct electro-oxidation of formic acid in fuel cells

Shu-Hong LI, Yue ZHAO, Jian CHU, Wen-Wei LI, Han-Qing YU, Gang LIU, Yang-Chao TIAN

《环境科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 388-394 doi: 10.1007/s11783-012-0475-y

摘要: Direct formic acid fuel cells are a promising portable power-generating device, and the development of efficient anodic catalysts is essential for such a fuel cell. In this work Pt-Bi nanoparticles supported on micro-fabricated gold wire array substrate were synthesized using an electrochemical deposition method for formic acid oxidation in fuel cells. The surface morphology and element components of the Pt-Bi/Au nanoparticles were characterized, and the catalytic activities of the three Pt-Bi/Au nanoparticle electrodes with different Pt/Bi ratios for formic acid oxidation were evaluated. It was found that Pt Bi /Au had a much higher catalytic activity than Pt Bi /Au and Pt Bi /Au, and Pt Bi /Au exhibited a current density of 2.7 mA·cm , which was 27-times greater than that of Pt/Au. The electro-catalytic activity of the Pt-Bi/Au electrode for formic acid oxidation increased with the increasing Bi content, suggesting that it would be possible to achieve an efficient formic acid oxidation on the low Pt-loading. Therefore, the Pt-Bi/Au electrode offers a promising catalyst with a high activity for direct oxidation of formic acid in fuel cells.

关键词: catalyst     electrochemical deposition     formic acid oxidation     fuel cell     gold wire array     microfabrication    

Catalytic decomposition of low level ozone with gold nanoparticles supported on activated carbon

Pengyi ZHANG , Bo ZHANG , Rui SHI ,

《环境科学与工程前沿(英文)》 2009年 第3卷 第3期   页码 281-288 doi: 10.1007/s11783-009-0032-5

摘要: Highly dispersed gold nanoparticles were supported on coal-based activated carbon (AC) by a sol immobilization method and were used to investigate their catalytic activity for low-level ozone decomposition at ambient temperature. Nitrogen adsorption-desorption, scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the catalysts before and after ozone decomposition. The results showed that the supported gold nanoparticles prepared with microwave heating were much smaller and more uniformly dispersed on the activated carbon than those prepared with traditional conduction heating, exhibiting higher catalytic activity for ozone decomposition. The pH values of gold precursor solution significantly influenced the catalytic activity of supported gold for ozone decomposition, and the best pH value was 8. In the case of space velocity of 120000h, inlet ozone concentration of 50mg/m, and relative humidity of 45%, the Au/AC catalyst maintained the ozone removal ratio at 90.7% after 2500min. After being used for ozone decomposition, the surface carbon of the catalyst was partly oxidized and the oxygen content increased accordingly, while its specific surface area and pore volume only decreased a little. Ozone was mainly catalytically decomposed by the gold nanoparticles supported on the activated carbon.

关键词: ozone decomposition     activated carbon     gold nanoparticles     catalysis     sodium citrate     microwave    

oocyst directed assembly of gold nanoparticles and graphene oxide

Sona Jain, Zhicheng Huang, Brent R. Dixon, Syed Sattar, Juewen Liu

《化学科学与工程前沿(英文)》 2019年 第13卷 第3期   页码 608-615 doi: 10.1007/s11705-019-1813-4

摘要: Understanding the interactions between inorganic nanomaterials and biological species is an important topic for surface and environmental chemistry. In this work, we systematically studied the oocysts of as a model protozoan parasite and its interaction with gold nanoparticles (AuNPs) and graphene oxide (GO). The as-prepared citrate-capped AuNPs adsorb strongly on the oocysts leading to a vivid color change. The adsorption of the AuNPs was confirmed by transmission electron microscopy. Heat treatment fully inhibited the color change, indicating a large change of surface chemistry of the oocysts that can be probed by the AuNPs. Adding proteases such as trypsin and proteinase K partially inhibited the color change. DNA-capped AuNPs, on the other hand, could not be adsorbed by the oocysts. GO was found to wrap around the oocysts forming a conformal shell reflecting the shape of the oocysts. Both citrate-capped AuNPs and GO compromised the membrane integrity of the oocysts as indicated by the propidium iodide staining experiment, and they may be potentially used for inactivating the oocysts. This is the first example of using nanomaterials to probe the surface of the oocysts, and it suggests the possibility of using such organisms to template the assembly of nanomaterials.

关键词: nanomaterials     toxicology     water     biosensors    

Catalytic activities and mechanism of formaldehyde oxidation over gold supported on MnO

Guanglong PANG,Donghui WANG,Yunhong ZHANG,Chunyan MA,Zhengping HAO

《环境科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 447-457 doi: 10.1007/s11783-015-0808-8

摘要: MnO microspheres with various surface structures were prepared using the hydrothermal method, and Au/MnO catalysts were synthesized using the sol-gel method. We obtained three MnO microspheres and Au/MnO samples: coherent solid spheres covered with wire-like nanostructures, solid spheres with nanosheets, and hierarchical hollow microspheres with nanoplatelets and nanorods. We investigated the properties and catalytic activities of formaldehyde oxidation at room temperature. Crystalline structures of MnO are the main factor affecting the catalytic activities of these samples, and γ-MnO shows high catalytic performance. The excellent redox properties are responsible for the catalytic ability of γ-MnO . The gold-supported interaction can change the redox properties of catalysts and accelerate surface oxygen species transition, which can account for the catalytic activity enhancement of Au/MnO . We also studied intermediate species. The dioxymethylene (DOM) and formate species formed on the catalyst surface were considered intermediates, and were ultimately transformed into hydrocarbonate and carbonate and then decomposed into CO . A proposed mechanism of formaldehyde oxidation over Au/MnO catalysts was also obtained.

关键词: MnO2 microspheres     Au/MnO2     formaldehyde oxidation     γ-MnO2    

Cystine-assisted accumulation of gold nanoparticles on ZnO to construct a sensitive surface-enhanced

《化学科学与工程前沿(英文)》 2023年 第17卷 第1期   页码 15-23 doi: 10.1007/s11705-022-2177-8

摘要: Recently, various semiconductor/metal composites have been developed to fabricate surface-enhanced Raman spectroscopy substrates. However, low metal loading on semiconductors is still a challenge. In this study, cystine was introduced to increase the accumulation of gold nanoparticles on zinc oxide, owing to the biomineralization property of cystine. Morphological analysis revealed that the obtained ZnO/Au/cystine composite not only had a higher metal loading but also formed a porous structure, which is beneficial for Raman performance. Compared with ZnO/Au, the ZnO/Au/cystine substrate displayed a 40-fold enhancement in the Raman signal and a lower limit of detection (10–11 mol·L−1) in the detection of rhodamine 6G. Moreover, the substrate has favorable homogeneity and stability. Finally, ZnO/Au/cystine displayed excellent performance toward crystal violet and methylene blue in a test based on river water samples. This study provided a promising method to fabricate sensitive semiconductor/noble metal-based surface-enhanced Raman spectroscopy substrates for Raman detection.

关键词: biomineralization     cystine     semiconductor/metal composite     SERS detection     Raman detection    

Modified iron-molybdate catalysts with various metal oxides by a mechanochemical method: enhanced formaldehyde

Xue Liu, Lingtao Kong, Shengtao Xu, Chaofan Liu, Fengyun Ma

《化学科学与工程前沿(英文)》 2021年 第15卷 第5期   页码 1099-1110 doi: 10.1007/s11705-020-2008-8

摘要: A mechanochemical method was employed to prepare modified iron molybdate catalysts with various metal salts as precursors. The physicochemical properties of the iron molybdate catalysts were characterized, and their performances in catalyzing the reaction from methanol to formaldehyde (HCHO) were evaluated. Iron molybdate catalysts doped with Co(NO ) ·6H O and Al(NO ) ·9H O resulted in high HCHO yields. Compared with a commercial catalyst, the HCHO yields in the reaction with the modified catalyst at an optimal Co/Mo molar ratio reached 97.37%. According to chemical state analysis, the formation of CoO and the efficient decrease in the MoO sublimation rate could be important factors enhancing the HCHO yield in reactions catalyzed with iron molybdate doped with different Co/Mo mole ratios.

关键词: iron molybdate catalyst     metal oxides     methanol to formaldehyde     Co/Mo ratio     formaldehyde yield    

Gold nanoparticles/single-stranded DNA-reduced graphene oxide nanocomposites based electrochemical biosensor

《化学科学与工程前沿(英文)》 2021年 第15卷 第6期   页码 1572-1582 doi: 10.1007/s11705-021-2112-4

摘要: High density and uniform distribution of the gold nanoparticles functionalized single-stranded DNA modified reduced graphene oxide nanocomposites were obtained by non-covalent interaction. The positive gold nanoparticles prepared by phase inversion method exhibited good dimensional homogeneity and dispersibility, which could readily combine with single-stranded DNA modified reduced graphene oxide nanocomposites by electrostatic interactions. The modification of single-stranded DNA endowed the reduced graphene oxide with favorable biocompatibility and provided the preferable surface with negative charge for further assembling of gold nanoparticles to obtain gold nanoparticles/single-stranded DNA modified reduced graphene oxide nanocomposites with better conductivity, larger specific surface area, biocompatibility and electrocatalytic characteristics. The as-prepared nanocomposites were applied as substrates for the construction of cholesterol oxidase modified electrode and well realized the direct electron transfer between the enzyme and electrode. The modified gold nanoparticles could further catalyze the products of cholesterol oxidation catalyzed by cholesterol oxidase, which was beneficial to the enzyme-catalyzed reaction. The as-fabricated bioelectrode exhibited excellent electrocatalytic performance for the cholesterol with a linear range of 7.5‒280.5 μmol·L‒1, a low detection limit of 2.1 μmol·L‒1, good stability and reproducibility. Moreover, the electrochemical biosensor showed good selectivity and acceptable accuracy for the detection of cholesterol in human serum samples.

关键词: reduced graphene oxide     gold nanoparticles     electrochemical biosensor     cholesterol oxidase     cholesterol    

Recent advances in gold-metal oxide core-shell nanoparticles: Synthesis, characterization, and their

Michelle Lukosi,Huiyuan Zhu,Sheng Dai

《化学科学与工程前沿(英文)》 2016年 第10卷 第1期   页码 39-56 doi: 10.1007/s11705-015-1551-1

摘要: Heterogeneous catalysis with core-shell structures has been a large area of focus for many years. This paper reviews the most recent work and research in core-shell catalysts utilizing noble metals, specifically gold, as the core within a metal oxide shell. The advantage of the core-shell structure lies in its capacity to retain catalytic activity under thermal and mechanical stress, which is a pivotal consideration when synthesizing any catalyst. This framework is particularly useful for gold nanoparticles in protecting them from sintering so that they retain their size, structure, and most importantly their catalytic efficiency. The different methods of synthesizing such a structure have been compiled into three categories: seed-mediated growth, post selective oxidation treatment, and one-pot chemical synthesis. The selective oxidation of carbon monoxide and reduction of nitrogen containing compounds, such as nitrophenol and nitrostyrene, have been studied over the past few years to evaluate the functionality and stability of the core-shell catalysts. Different factors that could influence the catalyst’s performance are the size, structure, choice of metal oxide shell and noble metal core and thereby the interfacial synergy and lattice mismatch between the core and shell. In addition, the morphology of the shell also plays a critical role, including its porosity, density, and thickness. This review covers the synthesis and characterization of gold-metal oxide core-shell structures, as well as how they are utilized as catalysts for carbon monoxide (CO) oxidation and selective reduction of nitrogen-containing compounds.

关键词: core-shell     characterization     core-shell structure     Different     stability    

Regulatory issues for genetically modified animals

Perry Bradbury HACKETT

《农业科学与工程前沿(英文)》 2020年 第7卷 第2期   页码 188-203 doi: 10.15302/J-FASE-2019307

摘要:

Precision genetics and breeding have the potential to meet the agricultural needs and goals of the world in the 21st century. These needs include increasing the efficiency of production of animals and improving their products with minimal impact on the environment. The USA is the major innovator in genomic science and the acknowledged leader in formulating policies to regulate genetic applications in medicine and agriculture. However, governments worldwide have been exceedingly reluctant to support the introduction of genetically modified (GM) animals into agriculture. Regulatory policies have stagnated due to legal guidelines that could not anticipate the needs and solutions that are evident today. This must change if we are to maintain planetary integrity. I propose a new, market-based regulatory model for GM livestock that has both a strong scientific foundation and has worked for 10000 years. The model is similar to that for information technology in which specific algorithms drive computer and cell phone applications. Genome engineers write genetic algorithms that drive the traits in biological organisms. Accordingly, GM products should be viewed in terms of their use and public benefit rather than by limitations to the genetic programing coming from a few highly vocal groups. Genetic algorithms (Genapps) of the 21st century will include not only introduction of synthetic genes, but also complete natural and synthetic biochemical pathways to produce agricultural products that are maximally efficient, healthy to humans and animals, and sustainable in an era of changing climates while avoiding environmental degradation.

关键词: algorithms     editing     FDA     GMO     recombinant DNA     USDA    

Modeling nanostructured catalyst layer in PEMFC and catalyst utilization

Jiejing ZHANG, Pengzhen CAO, Li XU, Yuxin WANG

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 297-302 doi: 10.1007/s11705-011-1201-1

摘要: A lattice model of the nanoscaled catalyst layer structure in proton exchange membrane fuel cells (PEMFC) was established by Monte Carlo method. The model takes into account all the four components in a typical PEMFC catalyst layer: platinum (Pt), carbon, ionomer and pore. The elemental voxels in the lattice were set fine enough so that each average sized Pt particulate in Pt/C catalyst can be represented. Catalyst utilization in the modeled catalyst layer was calculated by counting up the number of facets of Pt voxels where “three phase contact” are met. The effects of some factors, including porosity, ionomer content, Pt/C particle size and Pt weight percentage in the Pt/C catalyst, on catalyst utilization were investigated and discussed.

关键词: catalyst layer     PEM fuel cell     lattice model     Monte Carlo method     catalyst utilization    

标题 作者 时间 类型 操作

Gold modified cobalt-based Fischer-Tropsch catalysts for conversion of synthesis gas to liquid fuels

Alan J. McCue, Jura Aponaviciute, Richard P.K. Wells, James A. Anderson

期刊论文

Gold modified microelectrode for direct tetracycline detection

Hongtao WANG, Huimin ZHAO, Xie QUAN

期刊论文

Synthesis of boron modified CoMo/Al

Hui Shang, Chong Guo, Pengfei Ye, Wenhui Zhang

期刊论文

Nanostructured gold films exhibiting almost complete absorption of light at visible wavelengths

Hanbin Zheng, Christine Picard, Serge Ravaine

期刊论文

Steam reforming of toluene as a tar model compound with modified nickel-based catalyst

Omeralfaroug KHALIFA, Mingxin XU, Rongjun ZHANG, Tahir IQBAL, Mingfeng LI, Qiang LU

期刊论文

A Pt-Bi bimetallic nanoparticle catalyst for direct electro-oxidation of formic acid in fuel cells

Shu-Hong LI, Yue ZHAO, Jian CHU, Wen-Wei LI, Han-Qing YU, Gang LIU, Yang-Chao TIAN

期刊论文

Catalytic decomposition of low level ozone with gold nanoparticles supported on activated carbon

Pengyi ZHANG , Bo ZHANG , Rui SHI ,

期刊论文

oocyst directed assembly of gold nanoparticles and graphene oxide

Sona Jain, Zhicheng Huang, Brent R. Dixon, Syed Sattar, Juewen Liu

期刊论文

Catalytic activities and mechanism of formaldehyde oxidation over gold supported on MnO

Guanglong PANG,Donghui WANG,Yunhong ZHANG,Chunyan MA,Zhengping HAO

期刊论文

Cystine-assisted accumulation of gold nanoparticles on ZnO to construct a sensitive surface-enhanced

期刊论文

Modified iron-molybdate catalysts with various metal oxides by a mechanochemical method: enhanced formaldehyde

Xue Liu, Lingtao Kong, Shengtao Xu, Chaofan Liu, Fengyun Ma

期刊论文

Gold nanoparticles/single-stranded DNA-reduced graphene oxide nanocomposites based electrochemical biosensor

期刊论文

Recent advances in gold-metal oxide core-shell nanoparticles: Synthesis, characterization, and their

Michelle Lukosi,Huiyuan Zhu,Sheng Dai

期刊论文

Regulatory issues for genetically modified animals

Perry Bradbury HACKETT

期刊论文

Modeling nanostructured catalyst layer in PEMFC and catalyst utilization

Jiejing ZHANG, Pengzhen CAO, Li XU, Yuxin WANG

期刊论文