Ultraviolet-visible diffuse reflectance spectroscopy

The metal content analysis of the samples was effected by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES Varian Liberty II Instrument) after microwaves assisted mineralisation in hydrofluoric/hydrochloric acid mixture. Ultraviolet and visible diffuse reflectance spectroscopy (UV-Vis DRS) was carried out in the 200-900 nm range with a Lambda 40 Perkin Elmer spectrophotometer with a BaS04 reflection sphere. HF was used as a reference. Data processing was carried out with Microcal Origin 7.1 software. [Pg.286]

With the exception of single-crystal transmission work, most solids are too opaque to permit the conventional use of ultraviolet/visible (UV/VIS) electronic spectroscopy. As a result, such work must be performed through the use of diffuse reflection techniques [8-10]. Important work has been conducted in which UV/VIS spectroscopy has been used to study the reaction pathways of various solid state reactions. Other applications have been made in the fields of color measurement and color matching, areas which can be of considerable importance when applied to the coloring agents used in formulations. [Pg.5]

The simultaneous application of EPR/ultraviolet-visible diffuse reflectance spectroscopy (UV-vis-DRS)/online gas chromatography (GC) to characterize working catalysts was realized a few years ago 14), and laser-Raman spectroscopy has recently been coupled with these to provide the first such simultaneous application of three techniques 15). [Pg.267]

Spectroscopy. - In the following paragraphs we discuss how various spectroscopy tools have been used to illuminate the rich surface chemistry of supported polynuclear metal complexes. These methods include infrared (both diffuse reflectance and transmission), ultraviolet and visible (UV-Vis), x-ray photoelectron spectroscopy (XPS), and x-ray absorption, near edge spectroscopy s (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy s. [Pg.97]

This section summarizes the chemistry of the SC isobutane regeneration process. To understand the nature of the hydrocarbons that remain adsorbed on the surface of the USY zeolite catalyst both before and after SC isobutane regeneration, a series of ex-situ temperature-programmed oxidation (TPO), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and ultraviolet-visible (UV-vis) analyses was performed on samples submitted to different TOS 10 under isobutane/butene reaction conditions. [Pg.80]

Diffuse reflectance (DR) spectroscopy of Co permits the observation of d-d transitions in the near infrared and visible region and charge transfer (CT) transitions in the ultraviolet region. Co is the only common d ion and because of its stereochemistry the respective... [Pg.356]

Brittain, H.G. (1995) Ultraviolet/visible diffuse reflectance spectroscopy. Drugs Pharm. Sci., 70, 37-58. [Pg.290]

Several spectroscopic and nonspectroscopic techniques may be used to study the bonding nature of the adsorbate to the surface [2a, 4]. In the first case we want to emphasize the importance of diffuse reflectance techniques for absorption and emission studies in the ultraviolet (UV), Visible (Vis), and near infrared (NIR) spectral ranges. X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. In the second group, we refer the heat adsorption and the isotherm adsorption techniques, among others. [Pg.295]

Luan Z, Kevan L. Electron spin resonance and diffuse reflectance ultraviolet-visible spectroscopies of vanadium immobilized at surface titanium centers of titanosihcate... [Pg.535]

UV—vis DRS ultraviolet—visible diffuse reflectance spectroscopy XAS X-ray absorption spectroscopy XPS X-ray photoelectron spectroscopy XRD X-ray diffraction... [Pg.129]

ESC] X-ray diffiaction, Fourie-transform infrared and diffuse reflectance ultraviolet-visible spectroscopy 400-900°C/Fe203-Al203... [Pg.143]

Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...