In situ infrared, Raman and X-ray spectroscopy for the mechanistic understanding of hydrogen evolution reaction

Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy future.Computational methods have been widely used to study the reaction mechanism of the hydrogen evolution reaction(HER),but the calculation results need to be supported by experimental results and direct evidence to confirm the mechanistic insights.In this review,we discuss the fundamental principles of the in situ spectroscopic strategy and a theoretical model for a mechanistic understanding of the HER.In addition,we investigate recent studies by in situ Fourier transform infrared(FTIR),Raman spectroscopy,and X-ray absorption spectroscopy(XAS) and cover new findings that occur at the catalyst-electrolyte interface during HER.These spectroscopic strategies provide practical ways to elucidate catalyst phase,reaction intermediate,catalyst-electrolyte interface,intermediate binding energy,metal valency state,and coordination environment during HER.

Structural evolution study of additions of Sb_2S_3 and CdS into GeS_2 chalcogenide glass by Raman spectroscopy

The structures of pseudo-binary GeS2-Sb2S3, GeS2-CdS, Sb2S3-CdS, and pseudo-ternary GeS2-Sb2S3-CdS chalco- genide systems are systematically investigated by Raman spectroscopy. It is shown that a small number of [S3Ge-GeS3] structural units （SUs） and -S-S-/S8 groups exist simultaneously in GeS2 glass which has a three-dimensional continuous network backbone consisting of cross-linked corner-sharing and edge-sharing [GeS4] tetrahedra. When Sb2S3 is added into GeS2 glass, the network backbone becomes interconnected [GeS4] tetrahedra and [SbS3] pyramids. Moreover, Ge atoms in [S3Ge-GeS3] SUs tend to capture S atoms from Sb2S3, leading to the formation of [S2Sb-SbS2] SUs. When CdS is added into GeS2 glass, [Cd4GeS6] polyhedra are formed, resulting in a strong crystallization tendency. In addition, Ge atoms in [S3Ge-GeS3] SUs tend to capture S atoms from CdS, resulting in the dissolution of Ge-Ge bond. Co-melting of Sb2S3 or CdS with GeS2 reduces the viscosity of the melt and improves the homogeneity of the glass. The GeS2 glass can only dissolve up to 10-mol% CdS without crystallization. In comparison, GeS2-SbzS3 glasses can dissolve up to 20-mo1% CdS, implying that Sb2S3 could delay the construction of [Cd4GeS6] polyhedron and increase the dissolving amount of CdS in the glass.

Raman Scattering Study on Vibrational Modes and .Structure of Lanthanum Tellurite Glasses

Raman spectra of xLa203-（1-x）TeO2 （x=0, 0.05, 0.10, 0.15, 0.20, and 0.25） lanthanum tellurite glasses were measured and analyzed over the entire glass-forming region in an effort to quantitatively follow the structural changes caused by lanthanum oxide variation. For the first time, systematic intensity measurements have been performed to elucidate the composition induced structural changes in tile high-frequency stretching vibration region and a possible mechanism was proposed. The network structure of the glasses is formed by mixing TeO4 trigonal bipyramid and Te03 trigonal pyramid units. The change of the lanthanum oxide content results in conversion of the TeO4 units to TeO3 units with a varying number of non-bridging oxygen atoms. Analysis of the Raman band contours in terms of vibrations due to different oxygen bridged trigonal bipyramid and trigonal pyramid tellurite structural units, allowed to calculate the relative amounts of the species involved in the structural changes with composition. The fraction of the terminal oxygen atoms has been estimated from the Raman intensities with the aid of a structural model concerning the structure of tellurite network systems. The simulation of the experimental density of lanthanum tellurite glasses with modifier content up to 25% revealed that the short range order building units assumed here are sufficient to account for the overall structure in these glasses.

Synthesis, IR and Raman Spectroscopic Studies of (Ba,Sr)TiO₃Borosilicate Glasses with Addition of La₂O₃

A series of glasses were prepared by rapid melt quench method in the glass system (65-x)[(Ba0.6Sr0.4)TiO3]-30[2SiO2-B2O3]-5[K2O]-x[La2O3] (x = 0, 1, 2, 5 and 10). X-ray diffraction of glass samples were carried to check its amorphousity. Density of glass samples were measured using Archimedes principle. The refractive index of these glass samples lies between 2.39 to 2.80. Optical properties of these glass samples were studied using Infrared (IR) and Raman spectroscopic techniques. IR measurements were done over a continous spectral range 450 - 4000 cm-1 to study their stucture networking systematically while Raman spectra were recorded over a continous spectral range 200 - 2000 cm-1.IR spectra of all glass samples showed number of absorption peaks. These absorption peaks occurs due to asymetric vibrational streching of borate by relaxation of the bond B-O of trigonal BO3. The Raman spectra of all glass samples exhibited different spectral bands and intensity of these bands changes drastically. The network structure of these glass samples is mainly based on BO3 and BO4 units placed in different structural groups.

Determination of surface structure and the depth profile of silica glass by infrared spectroscopy

The surface structure and properties are different from those of the bulk, depending on the substrate materials and deposition condition, and playing an important role in precise optical components. The conventional spectroscopic methods to monitor the surface structure are restricted only in several layers of molecules. It is known that the penetration depth of the incident light increases with its wavelength and decreases with the angle of incidence. Thus infrared spectroscopy provides a powerful means for determination of surface structure and the depth profile up to micrometers. By recording the reflection spectra at different angles of incidence, the surface structure and its depth profile can be monitored successively. Further, the incident field has the subcomponents parallel and perpendicular to the surface, which excite the transverse and longitudinal optic modes, respectively. Change of the polarization direction of the incident light provides a practical function to study anisotropic property of the surface and the interaction between the transverse and longitudinal optic modes. In this work, infrared spectrophotometer was applied to investigate the depth profile in microstructure of silica glass. Combining with the glass fiber system, this technique can be used for in-situ control of the deposition process. In comparing with ellipsometry, this method reveals both structural and constitutional information.

Cooling rate calibration and mapping of ultra-short pulsed laser modifications in fused silica by Raman and Brillouin spectroscopy

This paper focuses on the preparation of a new extended set of calibrations of cooling rate(fictive temperature)in fused silica determined by inelastic light scattering and its subsequent use to characterize the local cooling rate distribution in ultra-short pulsed(USP)laser modification.In order to determine the thermal history(e.g.cooling rate and fictive temperature)of fused silica,high-resolution inelastic light-scattering experiments(Raman and Brillouin spectroscopy)were investigated.Calibrations were performed and compared to the existing literature to quantify structural changes due to a change of fictive temperature.Compared to existing calibrations,this paper provides an extension to lower and higher cooling rates.Using this new set of calibrations,we characterized a USP laser modification in fused silica and calculated the local fictive temperature distribution.An equation relating the fictive temperature(Tf)to cooling rates is given.A maximum cooling rate of 3000 K min-1 in the glass transition region around 1200℃ was deduced from the Raman analysis.The Brillouin observations are sensitive to both the thermal history and the residual stress.By comparing the Raman and Brillouin observations,we extracted the local residual stress distribution with high spatial resolution.For the first time,combined Raman and Brillouin inelastic light scattering experiments show the local distribution of cooling rates and residual stresses(detailed behavior of the glass structure)in the interior and the surrounding of an USP laser modified zone.

Raman Spectroscopy Analysis of Wollastonite/Tricalcium Phosphate Glass-Ceramics after Implantation in Critical Bone Defect in Rats

In this work wollastonite/tricalcium phosphate (W/TCP) glass-ceramics with three W/TCP weight ratios (20/80;60/40 and 80/20) were implanted in rat calvaria and the modifications taking place during implantation were studied by Raman spectroscopy. The experimental glass-ceramics were composed of different contents of βW, αW, βTCP, αTCP, and glassy phases. Materials were implanted for 7-, 15-, 45- and 120-day periods after which the implanted materials were recovered and analyzed by FT-Raman spectroscopy. The results suggested that the αW phase reabsorbs fast during implantation in the glass-ceramics 60/40 and 80/20, whereas βTCP and αTCP glass-ceramic are gradually attenuated and replaced by biological apatite-like bands. In the glass-ceramic 20/80, the bands related to the βTCP phase remained unvaried in all analyzed periods. New bands associated with the deposition of collagenous material appeared during implantation for all 60/40 and 80/20 glass-ceramics experimental groups, but important differences in intensities between both groups. The spectra corresponding to implants of 60/40 glass-ceramic at the 120-day period were very similar to those of the control group (normal cortical bone), with regards to Raman shifts and intensities, as well as in the FWHM value of the 962 cm-1 apatite band (ν1 PO4 in hydroxyapatite), evidencing that apatite deposited at the implant site has the same crystallinity than biological apatite in normal bone mineral. The glass-ceramic 20/80 behaved just as an osteoconductive filling material, while glass-ceramics 60/40 and 80/20 were able to induce deposition of organic matrix mineralized new tissue. The 60/40 glass-ceramic showed the best performance and the most similar Raman spectrum to normal cortical bone.

基于密度泛函理论对团簇CrPS_(4)的光谱分析

为快速、高效得到物质的谱图数据,利用计算化学方法,根据拓扑学原理,利用密度泛函理论,对团簇CrPS_(4)10种优化构型的红外光谱、拉曼光谱、偶极矩以及极化率进行了分析,并利用构型2^((4))的理论红外谱图与前人所得实际光谱图进行了对比。结果显示:CrPS_(4)红外光谱的波峰大致分布在300~700 cm^(-1)范围内,拉曼光谱的波峰范围主要分布在200~700 cm^(-1)范围内;团簇CrPS_(4)振动形式为伸缩振动时,其对入射光的吸收强度较大;在频率较低的波段,CrPS_(4)更易发生红外吸收,在频率较高的波段,更易发生拉曼散射;总偶极矩的排列顺序为2^((2))>6^((4))>4^((2))>3^((2))>3^((4))>4^((4))>1^((2))>2^((4))>5^((4))>1^((4)),偶极矩越大,红外活性越强;极化率大小关系满足5^((4))<1^((4))<6^((4))<4^((4))<3^((4))<1^((2))<2^((4))<2^((2))<3^((2))<4^((2)),极化率越大,拉曼活性越强;所有构型的3大主轴中,XX轴的极化率均大于YY轴与ZZ轴;构型2^((4))的理论光谱图与实际结果对比发现,两者光谱图波峰频率基本吻合,实验与理论分析互为补充。

拉曼光谱与中红外光谱融合技术快速定量食用酒精的乙醇浓度

目的利用拉曼光谱与中红外光谱的数据融合技术实现对食用酒精乙醇浓度(酒精度)的快速定量检测。方法首先,分别采集不同浓度食用酒精水溶液的拉曼光谱与中红外光谱。其次,采用多元散射校正(multiplicative scatter correction,MSC)、卷积平滑(Savitzky-Golay,S-G)、一阶求导的方法对原始数据进行预处理。然后,基于自举软缩减法(bootstrapping soft shrinkage,BOSS)和无信息变量消除算法(uninformative variable elimination,UVE)分别对预处理后的光谱数据进行特征提取,并利用X-Y距离样本集划分法(sample set partitioning based on joint X-Y distance,SPXY)将光谱数据划分为校正集和预测集。最后,建立基于拉曼光谱-中红外光谱数据融合的偏最小二乘回归(partial least squares regression,PLSR)食用酒精乙醇浓度预测模型,并利用麻雀搜寻算法优化的混合核极限学习机算法(sparrow search algorithm-optimized hybrid kernel extreme learning machine,SSA-HKELM)提升预测性能,实现对不同浓度食用酒精的快速、准确定量检测。结果与拉曼光谱数据、中红外光谱数据以及中红外与拉曼光谱的数据层融合构建的预测模型相比,中红外光谱与拉曼光谱特征层融合数据构建的预测模型具有更好的预测性能。其中,最优模型的校正集均方根误差(root mean squared error of calibration set,RMSEC)为0.98314,校正集决定系数(R_(c)^(2))为0.99634,预测集均方根误差(root mean squared error of prediction set,RMSEP)为1.03256,预测集决定系数(R_(p)^(2))为0.99036。结论中红外光谱与拉曼光谱特征层融合预测模型可以实现对不同浓度食用酒精的高效定量检测,为食用酒精的质量检测提供了有效的理论支持与技术保障。

红外、拉曼光谱的变压器油中糠醛检测方法对比研究

变压器油中的糠醛含量是电力变压器中绝缘老化的重要指标之一,在物质有效识别上红外及拉曼光谱具有检测速度快、分析速率快及无损检测等优势,开展了基于红外、拉曼光谱的变压器油中糠醛检测方法对比,探究适用于变压器油中糠醛红外、拉曼光谱的预处理及定量分析方法。基于傅里叶变换红外光谱仪和激光共聚焦拉曼光谱仪器对实验室配置的糠醛变压器油样检测并采集其光谱数据,采用小波变换、多项式最小二乘法和局部加权回归拟合对采集到的红外及拉曼光谱图进行预处理,综合考虑噪声、分辨率及有效信息丢失等,确定了多项式最小二乘法预处理效果最佳。基于高斯软件建立了糠醛分子模型,通过密度泛函仿真计算,研究了糠醛的红外及拉曼光谱吸收峰归属,结合实验测试光谱图,确定了变压器油中糠醛拉曼、红外检测特征峰分别为1 703和1 704 cm^(-1)。开展了红外及拉曼检测的重复性实验,两种检测方法的相对标准偏差分别为7.21%、 8.67%。通过绘制糠醛红外及拉曼的3D原位光谱图,分析红外及拉曼特征峰面积与不同糠醛浓度变压器油之间的关系,基于最小二乘法建立了变压器油中糠醛检测的红外及拉曼定量分析模型,拟合优度分别为0.998和0.885。对比两种检测方法的定量分析模型预测结果,表明拉曼光谱法检测下限低于红外光谱法,通过多项式最小二乘法预处理的光谱数据所构建的变压器油中糠醛检测红外及拉曼定量分析模型可以很好地预测变压器油中糠醛含量,为相关领域研究提供技术参考。

电化学谱学表征方法的应用与发展

经历两个多世纪的发展,电化学表征方法的理论和实验研究不断完善,在表界面精细结构表征、电化学反应机理研究等方面起到重要作用。电化学谱学表征技术的出现,填补了传统电化学表征方法在分子水平上鉴定电化学反应活性位点及中间物种的空白。本文总结了近年来红外光谱(IR)、表面增强拉曼光谱(SERS)及和频振动光谱(SFG)三种经典分子振动光谱电化学表征技术的研究进展。首先介绍了三种光谱的基本原理和电化学联用电解池的设计,然后从基础电化学理论出发,介绍其在模型单晶体系及界面水机理研究中的应用,进一步重点介绍了其在锂离子电池和燃料电池领域的相关研究进展,最后展望了电化学谱学表征技术的未来发展方向。

松辽盆地南部保康地区钻孔铀矿化地球化学特征及意义

松辽盆地是我国中-新生代陆相沉积盆地之一。文章以松辽盆地保康地区姚家组下段为主要研究目标层,采用地球化学和光谱学,针对赋矿砂岩中主量元素、微量元素、硫同位素和有机质特征进行分析研究,探讨了保康地区铀矿化特征和成矿前景。分析结果显示:保康地区矿化段具有脱Si,富Fe、Mn的特征,并且更加富集S和TOC;与铀相伴生的微量元素有Co、Ni、Mo、Cd、Re、Tl、Zr等,其中Mo、Cd、Re富集相对更加强烈,并且与铀具有显著的相关性;保康地区姚家组下段矿化样品δ^(34)S值为-17.7‰~-2.7‰,低于非矿化样品,说明黄铁矿中硫的主要来源为有机物热解(TDS);光谱学特征显示,样品中的有机质成熟度相对较高,与腐殖酸有一定相似性,推测是由深部烃源岩层演化而来的。综合分析铀矿石地球化学特征和有机质特征,认为保康地区铀矿化特征符合渗出砂岩型铀成矿作用的特点。

对位芳纶中间位结构单元含量的定量分析

在聚对苯二甲酰对苯二胺(PPTA)中引入间位结构可以调控其结晶和加工性能,因此确定其中的间位组分含量具有重要的实际意义。本文将PPTA和间位芳纶(PMIA)共混,采集其红外光谱,发现位于689 cm^(-1)处的间位取代苯环的C—H面内振动谱带强度与PMIA的含量呈现良好的线性正比关系,可以检测出共混样品中含有的质量分数2.0%的PMIA。以拉曼光谱分析共混物,利用位于1002 cm^(-1)的苯环呼吸振动谱带作为PMIA的特征峰,建立了峰强度与PMIA含量的标准曲线,具有良好的线性关系,能够检测出样品中低至质量分数0.25%的PMIA。2种方法对比,拉曼光谱法具有更高的准确度和灵敏度,优于红外光谱法。

光谱成像技术及其在植物中的应用研究进展

光谱成像技术能够同时获取样品的空间与化学信息,是研究复杂生物样品的有力工具。近年来,由于具备非入侵、无损测量等优势,光谱成像技术在食品与农产品检测、生物医学与环境监测等方面引起了越来越多的关注。同时,随着成像技术的发展,光谱成像技术在成像速度、波段数量、光谱分辨率、空间分辨率等方面的性能都得到了极大的提升,空间分辨率甚至可以打破衍射极限达到超分辨级别。本综述总结了拉曼光谱、红外光谱和近红外光谱等几种主要光谱成像技术的基本原理与性能,重点介绍了这类技术在植物细胞壁与木材研究、细胞结构与成分可视化、生物与非生物胁迫检测以及种子的无损测量等领域中的应用进展,并对这一类技术的发展潜力进行了探讨与总结,为今后光谱成像技术在植物研究领域的进一步发展与应用提供理论参考。

光谱法应用于地表水体微藻检测技术的研究进展

微藻中含有蛋白质、脂类、多糖、色素等多种营养成分,被广泛应用于医药、食品、水产养殖、生物能源等领域,具有很高的商业价值。因此,针对地表水体微藻的生物学研究具有十分重要的应用价值。光谱法作为一种操作简单、快速高效的检测方式,常用于确定物质结构和化学成分,在生物样品检测中具有良好优势。文章介绍了紫外-可见光谱、荧光光谱、红外光谱、拉曼光谱4种分子光谱技术,特别介绍了光谱技术结合计量学分析方法在微藻研究领域的应用。研究综述了光谱技术在成分分析、分类鉴定、生长代谢监测和选育等与微藻相关领域的国内外应用研究进展。光谱法在微藻领域的应用还处于发展阶段,在此基础上,对光谱技术在藻类领域的应用进行了展望,为光谱技术在微藻领域的应用提供新的研究方向。

基于NIR和Raman光谱的果蔬质量检测研究进展与展望

主要回顾了可见/近红外光谱分析技术和拉曼光谱分析技术在果蔬品质与安全检测领域的研究进展。可见/近红外光谱分析技术在果蔬品质的定量分析(包括糖、酸等内部成分含量和坚实度等组织物理属性等)、果蔬品质的定性分析(如缺陷检测、成熟度分级、货架期/储藏期判断等)、果蔬生长/加工过程监测、果蔬生长环境条件分析以及果蔬安全检测、果蔬品种与产地溯源等方面获得了广泛应用。拉曼光谱分析技术在果蔬内部成分分析(尤其是类胡萝卜素含量)、品质分级、成熟度辨别、缺陷/损伤检测等方面获得成功应用,在果蔬农残与微生物污染检测方面也比可见/近红外光谱分析技术更具潜力。此外,还分析归纳了光谱分析技术在果蔬品质与安全检测领域的优势与不足,并展望了今后的发展趋势。

Bi_2O_3-Ga_2O_3-CdO系统玻璃的Raman光谱和X射线光电子能谱研究

用X射线光电子能谱和Raman光谱研究了Bi2 O3-Ga2 O3-CdO系统玻璃的结构 .Raman光谱曲线被分离成 6个谱带 ,4条谱带分属于不同键长的Bi—O振动 ,一条谱带属于Ga—O振动 .Bi2 O3-Ga2 O3 二元系统玻璃的Raman散射最强峰位于 40 0～ 42 0cm- 1 ,当Ga3 + 离子被Cd2 + 离子取代后 ,Raman散射最强峰移向 5 95～ 6 30cm- 1 .随着Ga2 O3 含量的增加 ,位于高波数属于Bi—O振动的 2条谱带强度降低并朝低波数移动 ;位于低波数属于Bi—O振动的 2条谱带强度增加并朝高波数移动 ,添加CdO则出现相反的效应 .X射线光电子能谱显示出非常低的O1s电子结合能 ,甚至低于碱硅酸盐玻璃中非桥氧的O1s电子结合能 ,并且不可能分为桥氧和非桥氧 ,O1s和Bi4f的电子结合能都随Ga2 O3

水环境中微塑料的来源分布及其分子光谱检测技术的研究进展

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