Application of vibrational spectroscopy techniques for material identification from fire debris

The primary goal of this research is to demonstrate the use of vibrational spectroscopy techniques as a tool for the identification of materials post fire. This paper discusses the use micro-Raman spectroscopy and ATR-FTIR to identify materials found in fire debris. The polymeric materials under study were high density and low density polyethylene (HDPE and LDPE), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA) and cotton. These are commonly materials found in households around the world, their identification from the debris provides useful forensic information on the spatial distribution of fuels in a fire compartment, thus allowing for accurate analysis and modelling. Earlier work has established Raman spectroscopy to be a very good tool for material identification post fire. The addition of ATR-FTIR spectroscopy as a technique in developing this novel tool for identification of materials post fire has established vibrational spectroscopy in the area of fire investigation. This study indicated that the limitations associated with Raman spectroscopy in post fire identification, could be made insignificant by the strengths of ATR-FTIR spectroscopy and vice versa. To further establish the validity of this identification process principal component analysis was used to discriminate between the spectrum of the burnt materials and an error analysis computed. Both techniques demonstrated that identification could be done with very minimal confusion between the materials studied.     

Carbon dots from agroindustrial residues: a critical comparison of the effect of physicochemical properties on their performance as photocatalyst and emulsion stabilizer

Carbon dots have been synthesized through a pyrolysis route with agroindustrial wastes of Yerba Mate (YM), Avocado Seed (AS), and Orange Peel (OP) as raw materials. The selection of the pyrolysis temperature was according to the thermogravimetric profile of the raw materials. A thorough characterization by transmission electron microscopy (TEM), ζ-potential, ultraviolet visible spectroscopy (UV/vis), Raman, Fourier transform infrared (FTIR) spectroscopy, and steady-state, and time-resolved area normalized emission spectroscopy (TRANES) suggest spherical nanomaterials with diameters lower than 5.0 nm and polyfunctional surfaces with an abundance of negatively charged surface groups. Regarding their application as photocatalyst and as Pickering emulsion stabilizers, all materials have different performances. In the first case, almost 100% and 40% of the photodecoloration of methylene blue was achieved in 2 h by the materials obtained from YM and AS, respectively. Nevertheless, different mechanisms were proposed for both cases. Regarding their performance as Pickering emulsion stabilizers, all materials show different performances. Interestingly, Raman spectroscopy results provide useful information to understand the observed results.     

Azide-functionalization of carbon nanotubes by electrochemical oxidation of N3- in situ

Azide-functionalization of single-walled carbon nanotubes （SWCNTs） was achieved by electrochemical oxidation of N3 in situ. The functionalized nanotubes were characterized in details by single internal reflection infrared spectroscopy （ATR-FTIR） and thermogravimetic analysis （TGA/MS）. The results revealed that a covalent C-N bond had formed and this might provide an effective method for the preparation of azide-functionalized materials, especially carbon materials. The degree of functionaliza- tion was measured by X-ray photoelectron spectroscopy （XPS）.     

Preparation and properties of calcium silicate hydrate-poly(vinyl alcohol) nanocomposite materials

Summary A series of calcium silicate hydrate (C-S-H)-polymer nanocomposite (C-S-HPN) materials were prepared by incorporating poly(vinyl alcohol) (PVA) into the inorganic layers of C-S-H during precipitation of quasicrystalline C-S-H from aqueous solution. The as synthesized C-S-HPN materials were characterized by Fourier-transform infrared photoacoustic (FTIRPAS) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy/energy dispersed spectroscopy (SEM/EDS), thermogravimetric analysis (TG), differential thermogravimetry (DTG) and differential scanning calorimetry (DSC). The XRD peaks of C-S-HPN materials suggest the intermediate organizations presenting both intercalation of PVA and exfoliation of C-S-H. The SEM micrographs of C-S-H, PVA and C-S-HPN materials with different PVA contents exhibit the significant differences in their morphologies. Effects of the material compositions on the thermal stability of a series of C-S-HPN materials along with PVA and C-S-H were studied by TG, DTG and DSC. Three significant decomposition temperature ranges were observed in the TG curves of all C-S-HPN materials.     

One-Pot Functionalization of Graphene with Porphyrin through Cycloaddition Reactions

Two types of graphene‐based hybrid materials, graphene‐TPP (TPP=tetraphenylporphyrin) and graphene‐PdTPP (PdTPP=palladium tetraphenylporphyrin), were prepared directly from pristine graphene through one‐pot cycloaddition reactions. The hybrid materials were characterized by thermogravimetric analysis (TGA), by TEM, by UV/Vis, FTIR, Raman, and luminescence spectroscopy, and by fluorescence/phosphorescence lifetime measurements. The presence of the covalent linkages between graphene and porphyrin was confirmed by FTIR and Raman spectroscopy and further supported by control experiments. The presence of TPP (or PdTPP) in the hybrid material was demonstrated by UV/Vis spectroscopy, with TGA results indicating that the graphene‐TPP and graphene‐PdTPP hybrid materials contained approximately 18 % TPP and 20 % PdTPP. The quenching of fluorescence (or phosphorescence) and reduced lifetimes suggest excited state energy/electron transfer between graphene and the covalently attached TPP (or PdTPP) molecules.     

Recent progress in investigations of surface structure and properties of solid oxide materials with nuclear magnetic resonance spectroscopy

In this review, some of the latest research developments on the characterization of the structure and properties of oxide materials by applying solid-state nuclear magnetic resonance spectroscopy (NMR), including the use of dynamic nuclear polarization (DNP) NMR, ¹⁷O NMR combined with surface selective labeling and ³¹P NMR coupled with phosphorous-containing probe molecules, are discussed.     

PW_(11)/SBA-15介孔杂化材料的直接合成与表征

采用三嵌段共聚物EO20PO70EO20(P123)为模板剂,正硅酸乙酯(TEOS)和缺位Keggin型多金属氧酸盐Na7PW11O39(PW11)为无机前驱体,由共缩合法一步合成了PW11/SBA-15介孔杂化材料.通过红外(IR)光谱、紫外-可见漫反射光谱(UV-Vis/DRS)、X射线衍射(XRD)、低温N2吸附、透射电子显微镜(TEM)等手段对杂化材料和合成过程进行了表征.结果表明:杂化材料中不仅多金属氧酸盐的Keggin单元保留完整,且共价键联于介孔孔道内部,而且样品基本具有规整有序的六方介孔结构.TEOS预水解时间的长短对有序结构的构筑有明显影响,随预水解时间延长,样品的介观有序性增加.这是因为多金属氧酸盐对模板剂P123有盐析作用,其作用大小与多金属氧酸盐前驱物的溶解度有关.     

Synthesis, characterization, and catalytic performance of copper-containing SBA-15 in the phenol hydroxylation

A series of copper-containing SBA-15 samples were successfully synthesized via evaporation-induced self-assembly route. The resulting materials were characterized by X-ray diffraction (XRD), (29)Si MAS NMR spectroscopy, transmission electron microscopy (TEM), N(2) sorption, inductively coupling plasma-atomic emission spectrometer (ICP-AES), thermogravimetry, and differential thermal analysis (TG-DTA), Fourier-transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectra (UV-vis) and X-ray photoelectron spectroscopy (XPS). The results indicated that: (1) all the samples exhibited typical hexagonal arrangement of mesoporous structure; (2) copper ions could be incorporated into the framework of SBA-15; (3) the addition of urea in the hydrothermal stage efficiently reduced the leaching of copper and improved the thermal stability of the mesoporous materials. Catalytic performances of the obtained materials were evaluated in the hydroxylation of phenol with H(2)O(2). The catalytic tests showed that the synthesized materials exhibited high activity for this reaction and copper ions in the framework were more active than copper species in the extra-framework position. The nitric acid treatment on the samples removed the bulk CuO species, which resulted in a dramatic increase in the catalytic activity.     

Experimental and DFT analysis of onion peels for its inhibition behavior against mild steel corrosion in chloride solutions

Natural materials are good options for being used as inhibitors due to their high biodegradability, reasonable cost, easiness in use and high efficiency. In this regard, waste natural materials are very useful because they have all the properties of natural materials and easily available at very low cost (almost free). This work reports a similar kind of waste natural materials namely onion peels. The water extract of onion peels (WEOP) is characterized by UV–vis spectroscopy (UVS) and FTIR spectroscopy (FTIS). WEOP is tested for corrosion inhibition of mild steel (MS) in 1 M NaCl by various techniques like typical weight loss measurements (WLM), open circuit potential (OCP) curves, Tafel polarization (TP) curves, electrochemical impedance spectroscopy (EIS) and surface scanning microscopy (SEM). The maximum inhibition of mild steel corrosion is 90% (WLM). The reason of inhibition based on experimental analysis is proposed as adsorption of extract molecules on MS, which is found true in SEM images and Langmuir isotherm study. The WEOP is also examined by density functional theory principles, which recommends that the extract molecules can be easily adsorbed on MS and can stop corrosion of MS in NaCl solutions. Based on investigation, a schematic is introduced for compact explanation.     

钴掺杂二氧化钛的光催化制氢性能

采用聚合络合法（PCM）制备出钴掺杂二氧化钛（CO/TiO₂）光催化剂.以热重-差示扫描量热同步热分析（TGA-DSC）,傅里叶变换红外（FT-IR）光谱,X射线粉末衍射（XRD）,氮气吸附-脱附,紫外-可见漫反射光谱（UV-Vis DRS）,X射线光电子能谱（XPS）等手段对材料进行了表征.采用光催化制氧作为探针反应,以氧气的产量评价材料的光催化性能结果表明:采用聚合络合法制备的样品主体成分为锐钛矿晶型的二氧化钛,钴元素呈高度分散,钴的掺杂能够明显提升二氧化钛光催化材料的光催化制氢活性,当钴钛物质的量之比为0.3%时,催化剂具有最佳的光催化制氢活性,达到2499μmol,是同等条件下制备的无掺杂二氧化钛的近六倍.还对钴离子掺杂增强机理进行了探讨.     

Effect of graphite features on the properties of metal-organic framework/graphite hybrid materials prepared using an in situ process

Metal-organic framework (MOF)/graphite hybrid materials were prepared using an in situ process. Graphites with various chemical and physical features were used, and HKUST-1 was selected as the MOF component. The samples (parent materials and hybrid materials) were characterized by X-ray diffraction, nitrogen sorption, scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Then they were tested as ammonia adsorbents in dynamic conditions. The results indicate that the functionalization of graphite is important to build the hybrid materials with synergistic properties. The lack of functional groups on graphite results in the formation of a simple physical mixture. Besides the surface chemistry of the graphitic component, the physical parameters (porosity and size of flakes) also seem to influence the formation of the hybrid materials. It is observed that the graphite particles disturb the formation of HKUST-1 and induce a different crystal morphology (more defects and increased surface roughness) than the one observed when MOF is formed in the absence of a substrate. The latter behavior causes less ammonia to be adsorbed on the hybrid materials than is expected for the simple physical mixture of HKUST-1 and graphite. The MOF structure collapses (in HKUST-1 and the hybrid materials) upon ammonia adsorption and leads to the formation of new species.     

Surface Diels-Alder reactions as an effective method to synthesize functional carbon materials

The post-synthesis chemical modification of various porous carbon materials with unsaturated organic compounds is reported. By this method, amine, alcohol, carboxylate, and sulfonic acid functional groups can be easily incorporated into the materials. Different carbonaceous materials with surface areas ranging from 240 to 1500?m(2)g(-1) and pore sizes between 3.0 and 7.0?nm have been studied. The resulting materials were analyzed by elemental analysis, nitrogen sorption, FTIR spectroscopy, zeta-potential measurements, thermogravimetric analysis, photoelectron spectroscopy, and small-angle X-ray scattering. These analyses indicated that the degree of functionalization is dependent on the nature of the dienophile (reactivity, steric hindrance) and the porosity of the carbon material. As possible applications, the functionalized carbonaceous materials were studied as catalysts in the Knoevenagel reaction and as adsorbents for Pb(2+) from aqueous solution.     

表面改性炭材料在微生物燃料电池中的应用(英)

研究了在空气阴极微生物燃料电池中修饰方法如硝酸处理和硝酸-氨水酸碱等对XC-72R作为阴极氧还原催化剂催化活性的影响,并且使用傅里叶变换红外光谱(FTIR)、Boehm滴定法和X射线光电子能谱(谱(XPS)等手段对催化剂进行了表征.FTIR测试证明硝酸处理可引入含氧基团氨水处理可引入含氮基团.另外,还测试了含有不同表面官能团的XC-72R对氧还原的活性,并将其作为阴极催化剂用在MFC中,测试了电池性能.实验表明,经酸碱修饰的XC-72R作为空气阴极MFC的催化剂具有很好的应用前景.     

Synthesis and characterization of conjugated polymers and their blends for optoelectronic applications

Various polymeric blends of hole transporting materials, (such as MEH-PPV and P3HT) and electron transporting materials (such as poly(phenyl-vinyl-quinoline) and poly[2-(4-methacryloxyphenyl)-5-phenyl)-1,3,4-oxadiazole]) have been prepared and investigated. Moreover a soluble, main chain oxadiazole bearing polyether has been synthesized, aiming towards an efficient electron transporting polymeric material which was also used for blend preparation together with P3HT. A deeper investigation into their spectroscopic characteristics using, primarily, FT-IR spectroscopy, but also UV-Vis spectroscopy has been conducted. The surface morphology of these blends was investigated using Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) in an attempt to gather information for their solid state properties and morphologies. Finally, DSC measurements provided additional insight into the thermal behaviour of these materials.     

Controlling the density of amine sites on silica surfaces using benzyl spacers

The synthesis and characterization of benzyl-spaced aminopropyl-functionalized mesoporous silica is reported by a method designed to reduce silanol-amine and amine-amine interactions. The new material is characterized by N(2) physisorption, thermogravimetric analysis, potentiometric titration, X-ray diffraction, FT-Raman spectroscopy, and (13)C and (29)Si solid-state NMR spectroscopy. The degree of clustering of the amines is studied by solid-state fluorescence spectroscopy of 1-pyrenecarboxylic acid bound to the deprotected benzyl-spaced aminosilica. The results obtained provide evidence of an amine loading comparable to traditional dense amine grafting approaches on SBA-15. Thermogravimetric analysis, FT-Raman spectroscopy, and (13)C solid-state NMR spectroscopy results show evidence that the protected imine can be quantitatively cleaved to yield the corresponding amine. As evidenced by fluorescence spectroscopy, the benzyl-spaced material is isolated enough to prevent excimer formation of the probe molecule, unlike aminopropyl-functionalized silica materials prepared by traditional grafting approaches.     

Functionalized mesoporous silica supported copper(II) and nickel(II) catalysts for liquid phase oxidation of olefins

Highly ordered 2D-hexagonal mesoporous silica has been functionalized with 3-aminopropyltriethoxysilane (3-APTES). This is followed by its condensation with a dialdehyde, 4-methyl-2,6-diformylphenol to produce an immobilized Schiff-base ligand (I). This material is separately treated with methanolic solution of copper(II) chloride and nickel(II) chloride to obtain copper and nickel anchored mesoporous materials, designated as Cu-AMM and Ni-AMM, respectively. The materials have been characterized by Fourier transform infrared (FT-IR) and UV-vis diffuse reflectance (DRS) spectroscopy, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), N(2) adsorption-desorption studies and (13)C CP MAS NMR spectroscopy. The metal-grafted mesoporous materials have been used as catalysts for the efficient and selective epoxidation of alkenes, viz. cyclohexene, trans-stilbene, styrene, α-methyl styrene, cyclooctene and norbornene to their corresponding epoxides in the presence of tert-butyl hydroperoxide (TBHP) as the oxidant under mild liquid phase conditions.     

Multitechnique spectroscopic analysis of polymer surfaces

The analysis of polymeric materials by modern surface sensitive spectroscopic experiments has yielded results which can be useful in solving both fundamental structural questions and problems which arise with the use of working materials. This paper will review the developments in polymer surface analysis which utilize the techniques of X-ray photoelectron spectroscopy (XPS or ESCA), secondary ion mass spectrometry (SIMS), ion scattering spectrometry (ISS), and fourier transform IR (FT-IR) spectroscopy stressing the complementary nature of the information derived from these methods.     

基于芘并咪唑的电致发光材料的合成与表征

以芘和咪唑为基本构筑单元,利用"一锅法"合成了一系列芘并咪唑衍生物PyPI,PyTPAI,PyCzI和Pyd-CzI.采用质谱、核磁和元素分析等手段表征了化合物的结构.通过调节与芘并咪唑相连接的共轭基团的种类、大小和空间构型,实现对分子热学性质,分子轨道能级和光电性质的调控.进一步制备了有机电致发光器件,得到了较好的器件性能.     

Structural properties of lithium thio-germanate thin film electrolytes grown by radio frequency sputtering

In this study, lithium thio-germanate thin film electrolytes have been successfully prepared by radio frequency (RF) magnetron sputtering deposition in Ar gas atmospheres. The targets for RF sputtering were prepared by milling and pressing appropriate amounts of the melt-quenched starting materials in the nLi(2)S + GeS(2) (n = 1, 2, and 3) binary system. Approximately 1 μm thin films were grown on Ni coated Si (Ni/Si) substrates and pressed CsI pellets using 50 W power and 25 mtorr (～3.3 Pa) Ar gas pressures to prepare samples for Raman and Infrared (IR) spectroscopy, respectively. To improve the adhesion between the silicon substrate and the thin film electrolyte, a sputtered Ni layer (～120 nm) was used. The surface morphologies and thickness of the thin films were determined by field emission scanning electron microscopy (FE-SEM). The structural properties of the starting materials, target materials, and the grown thin films were examined by X-ray diffraction (XRD), Raman, and IR spectroscopy.     

Porous Siloxane-Silica Hybrid Materials by Sol-Gel Processing

Porous hybrid materials have been fabricated by sol-gel processing of tetraethoxysilane (TEOS) and 1,3,5,7-tetramethyl-tetrakis(ethyltriethoxysilane)-cyclotetrasiloxane (1) in the presence of the cationic surfactant, cetyltrimethylammonium bromide (CTAB). The chemical and physical properties of these materials have been analysed by FT-IR spectroscopy, solid state ²⁹Si NMR spectroscopy, powder X-ray diffraction and nitrogen adsorption-desorption studies. FT-IR spectroscopy established that the CTAB surfactant can be extracted from a crushed gel using ethanol as a solvent. Solid state ²⁹Si NMR spectroscopy showed the presence of D, T and Q species as expected from the structure of the precursors. Broad bands observed for the D units at –18 ppm and the T units at –63 ppm suggested that the cyclotetrasiloxane was held in a rigid environment and bound to the Q species of the silica matrix derived from the TEOS. NMR spectroscopy confirmed that solvent extraction resulted in further condensation of the silica matrix. Powder X-ray diffraction indicated that the materials possess short-range order and small domain sizes, as shown by broad diffraction peaks. The condensation induced by solvent extraction led to a decrease in the lattice and domain size of the samples, generally resulting in a less ordered material. Nitrogen adsorption-desorption isotherms were typical of microporous materials with pore diameters of 18 Å and a narrow size distribution.