Evonik Degussa Research Articles

Low-frequency ultrasound induces oxygen vacancies formation and visible light absorption in TiO 2 P-25 nanoparticles

Low-frequency ultrasound (LFUS) irradiation induces morphological, optical and surface changes in the commercial nano-TiO 2-based photocatalyst, Evonik–Degussa P-25. Low-temperature electron spin resonance (ESR) measurements performed on this material provided the first experimental evidence for the formation of oxygen vacancies ( V o), which were also found responsible for the visible-light absorption. The V o surface defects might result from high-speed inter-particle collisions and shock waves generated by LFUS sonication impacting the TiO 2 particles. This is in contrast to a number of well-established technologies, where the formation of oxygen vacancies on the TiO 2 surface often requires harsh technological conditions and complicated procedures, such as annealing at high temperatures, radio-frequency-induced plasma or ion sputtering. Thus, this study reports for the first time the preparation of visible-light responsive TiO 2-based photocatalysts by using a simple LFUS-based approach to induce oxygen vacancies at the nano-TiO 2 surface. These findings might open new avenues for synthesis of novel nano-TiO 2-based photocatalysts capable of destroying water or airborne pollutants and microorganisms under visible light illumination.

Photocatalytic NOx abatement: The role of the material supporting the TiO2 active layer

The importance of the choice of a suitable substrate as supporting material for photoactive TiO2, either in the form of powders or thin films or in photoactive paints, is frequently disregarded. In this paper four different supports (stainless steel, sand-blasted stainless steel, Teflon and glass) are object of investigation. The final aim is to verify the presence of interactions between the photocatalyst (AEROXIDE® TiO2 P25 by Evonik Degussa Corporation) and the support, directly involved in the photocatalytic activity in the NOx abatement. The characterization results have been correlated with the photoactivity of the different samples. In particular, a coating of about 6–9μm seems to allow a photocatalytic result free from any positive or negative interference with the supporting material, therefore giving reliable results about the photoactivity of the TiO2 under investigation.

Continuous Manufacture of Submicron Thick Ceramic Green Tapes and Coatings Demonstrated for TCO Nano Particles

This presentation introduces a new technique to manufacture continuously submicron thick ceramic green tapes and coatings from nano particulate suspensions. A profiled steel rod is used to coat large areas with a very low film thickness of down to 250 nm. This technique can easily be scaled up and is therefore suitable for mass production at high throughput and low cost. The profile rod technique could be a method to overcome the limit of the tape casting process and therefore this technique exhibits an enormous economical potential. The technique is demonstrated at the example of nano particulate indium tin oxide (ITO) and zinc oxide (ZnO) particles, which are both transparent conductive oxides (TCOs) and therefore interesting materials for printed displays etc. Nano particles from Evonik Degussa GmbH were first dispersed and stabilized in organic solvents. Subsequently, dispersions as well as slurries were prepared. Their rheological and wetting behavior were studied and the effect on the microstructure of the resulting layer was evaluated. Furthermore, the influence of the processing parameters during coating on the layer quality was analyzed. Finally, the functionality of the printed layers was proven by electrical measurements as well as the assembly of electron devices.

CO2 photoreduction at enzyme-modified metal oxide nanoparticles

A model system for photoreduction of CO2 to CO using visible light has been extensively studied, using a catalyst for which the CO2/CO reaction is electrochemically reversible. The hybrid system comprises metal oxide nanoparticles functionalised with the enzyme carbon monoxide dehydrogenase (CODH), and sensitised to visible light using a ruthenium bipyridyl photosensitiser. An anatase/rutile TiO2 mixture (Evonik Degussa P25) was selected as the most suitable semiconductor, and CO production rates and stability were examined as a function of each component (photosensitiser, enzyme and TiO2). Tolerance to O2 and effects of different electron donors were also investigated, together with strategies to control enzyme binding at the surface of TiO2 in order to enhance overall activity.

Experimental and Theoretical Studies of a Dividing-Wall Column Used for the Recovery of High-Purity Products

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionExperimental and Theoretical Studies of a Dividing-Wall Column Used for the Recovery of High-Purity ProductsGerit Niggemann*†, Christoph Hiller, and Georg FiegView Author Information Institute of Process and Plant Engineering, Hamburg University of Technology, Schwarzenbergstrasse 95c, 21073 Hamburg, Germany* To whom correspondence should be addressed. Tel.: +49 40 42878-3241. Fax: +49 40 42878-2992. E-mail: [email protected]†Current address: Evonik Degussa GmbH, DG-TE-VT-F, Hanau−Wolfgang, Germany.Cite this: Ind. Eng. Chem. Res. 2010, 49, 23, 12331Publication Date (Web):October 27, 2010Publication History Received10 September 2010Published online27 October 2010Published inissue 1 December 2010https://doi.org/10.1021/ie1018832Copyright © 2010 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views307Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (21 KB) Get e-Alerts Get e-Alerts

Rapid Bonding/Debonding on Demand: Reversibly Cross-Linked Functional Polymers via Diels−Alder Chemistry

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTRapid Bonding/Debonding on Demand: Reversibly Cross-Linked Functional Polymers via Diels−Alder ChemistryAndrew J. Inglis†, Leena Nebhani†, Ozcan Altintas†, Friedrich Georg Schmidt‡, and Christopher Barner-Kowollik*†View Author Information† Preparative Macromolecular Chemistry, Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76128 Karlsruhe, Germany‡ Evonik Degussa GmbH, Paul-Baumann-Strasse 1, 45764 Marl, Germany*Corresponding author. E-mail: [email protected]Cite this: Macromolecules 2010, 43, 13, 5515–5520Publication Date (Web):June 10, 2010Publication History Received29 April 2010Revised4 June 2010Published online10 June 2010Published inissue 13 July 2010https://doi.org/10.1021/ma100945bCopyright © 2010 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views3725Altmetric-Citations121LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (2 MB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Anions,Materials,Mixtures,Organic compounds,Polymers Get e-Alerts

Comparison of Photocatalytic Activities of Commercial Titanium Dioxide Powders Immobilised on Glass Substrates

AbstractSemiconductor photocatalysis is an advanced oxidation technology reported to be effective for the degradation of a wide range of organic pollutants found in water. Titanium dioxide is the most suitable photocatalyst for water treatment as it is insoluble under normal pH conditions, is photoactive, photostable, readily available and inexpensive. In this work Millennium Chemicals PC500, PC105, PC100, PC50, PC10 and Evonik Degussa P25 powders were immobilised onto borosilicate glass, via dip-coating and spray coating, producing thick films ranging from 0.2 to 1.4 mg catalyst per square cm of glass substrate. The photocatalytic activity of the immobilised films was compared under back-face UVA irradiation in a stirred-tank reactor using formic acid and phenol as model pollutants. Based upon the rate constant derived from the removal of the parent compound, and using the optimum catalyst loading determined under the experimental conditions employed, the order of photocatalytic activity for the degradation of formic acid was found to be P25 > PC100 > PC50 > PC105 ≥ PC500 > PC10, while for phenol degradation the order was P25 > PC50 > PC105 > PC100 ≥ PC500 > PC10.

The modified outflow funnel — A device to assess the flow characteristics of powders

Flow regulators are added to solid pharmaceutical formulations to improve the flow properties of powder mixtures. During the blending process the glidants adsorb successively at the surface of the host particles and thus lead to a reduction of attractive forces. A large variety of flow additives based on silicon dioxide is commercially available, but not all glidants are just as well suited for each technological problem or each cohesive bulk powder. To assess the improvement of the flowability parameters caused by a glidant a classification system and an adequate measuring device is needed. We would like to present a new measuring device to evaluate the flow enhancing potency of glidants. The modified outflow funnel features a stirrer that acts in the region of bulk arches obstructing the outflow process of a cohesive powder. By destruction of the bulk arches powder outflow is enabled and the time needed for emanation can be measured as a parameter of the flow properties. In addition other measuring parameters like the force needed to destroy the bulk arches are capable to evaluate the flowability of the powder mixture. Binary powder mixtures consisting of corn starch and flow regulator were blended in a Turbula® mixer for a defined period of time. The flow regulators were represented by fumed silica and a selection of various types of SIPERNAT ® precipitated silica provided by Evonik Degussa GmbH, Hanau, Germany. Flowability parameters of the mixtures were characterized with a modified outflow funnel, Hausner Ratio and a shear tester.

Effects of feeding varied levels of balanced protein on growth performance and carcass composition of growing and finishing pigs (2009)

A total of 1,003 barrows and gilts (PIC 337 × 1050, initially 113.5 lb) were used in an 88-d study to determine effects of various levels of balanced amino acid density on growth performance and carcass characteristics. Balanced amino acid refers to balancing the dietary amino acids according to the ideal protein ratio, at least for the first 4 limiting amino acids; the other amino acids may be at or higher than required levels. In this study, this balance was accomplished by using supplemental amino acids and formulating to meet the first 4 limiting amino acids: lysine, threonine, methionine, and tryptophan. Three experimental diets were tested using 6 replicate gilt and 7 replicate barrow pens per treatment. These diets were tested over 2 different phases, a grower phase (d 0 to 28) and a finishing phase (d 28 to 88). Dietary treatments included a diet that met the NRC (1998)5 requirements, a diet that met Evonik Degussa (Hanau, Germany) requirements, and a diet that was formulated to be 10% greater than Evonik Degussa recommendations. No gender × dietary treatment interactions were observed (P > 0.30) for any of the growth or carcass characteristics. During the growing phase, ADG and F/G improved (linear; P 0.62) in ADG, ADFI, or F/G from increasing dietary lysine or balanced protein levels. Gilts had decreased (P 0.28) for carcass yield, backfat depth, loin depth, percentage lean, live value, or calculated income over feed cost. In this experiment, increasing the amino acid density (dietary lysine level) over the NRC (1998) requirement offered improvements in the grower phase but not the finishing phase.

3‐D Modeling of Shock‐induced Precursor Decomposition and Nano‐Particle Growth

AbstractIn the ongoing joint project “Gasdynamically induced nano–particles” (PAK 75/1) a novel method of gas–phase synthesis of nano–particles is being developed [1]. This project is supported by the Deutsche Forschungsgemeinschaft (DFG), the pilotfacility is erected in collaboration with Evonik Degussa, Hanau, Germany. The key features of the new method are the static temperature increase across a stationary shock to provide ignition conditions of the precursor and the subsequent gasdynamic quenching of the particle growth when the desired particle diameter of 10−8m is reached. In this work the decomposition of the precursor, the reactive heat release and the particle growth are coupled with the 3–D transonic flow inside the particle reactor. The simulation results show the effect of shock/boundary layer interactions on the decomposition reaction as well as the effects of the reactive heat release on the shock location and the resulting particle size distribution. The Reynolds number at the shock location is Rex=9·106, the boundary layer thickness is δ=2.2 mm and the pre–shock Mach number is M=1.58. The complex transonic reactive flow within the particle reactor requires a high mesh resolution to resolve the local details of the internal flow problem. In addition, an efficient particle model is required. The formation and growth of the particles are modeled by three separate reactions. The primary reaction is the decomposition of the precursor and the production of monomers. It is modeled by a one step reaction described by an Arrhenius equation. The secondary reaction, the formation of critical nuclei is in our case negligible, because of the high supersaturation ratio of the order of 103 instantly after the primary reaction, where the monomers are already critical nuclei. The tertiary reaction is the particle growth by surface condensation, coagulation and single–aggregation. To simulate the particle growth we apply a local monodisperse bimodal formulation. Thereby, the monodisperse model of Kruis et al. [2] is extended by an additional discrete monodisperse mode for the critical nuclei. This method describes the local particle size due to turbulent mixing, coagulation and coalescence. The coagulation starts in the Knudsen regime Kn ≫ 1 and reaches the continuum regime with particle diameters of the order of 10−8m and a mean free path of the same order of magnitude. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Radical innovation through internal corporate venturing: Degussa's commercialization of nanomaterials

Internal corporate venturing enables radical innovation within established firms in mature markets. Without effectively designed and managed internal corporate ventures, the organizational constraints of established firms will strongly favour incremental innovation over radical innovation. This paper investigates the evolution of a successful internal corporate venture within a large, incumbent chemical firm, now known as Evonik Degussa, to reveal the challenges, organizational design, and management strategies of their commercialization of radical nanomaterials technology. The commercialization of nanomaterials technology is of great interest to incumbent materials and chemical firms and to independent ventures, but the radical, generic, and capital intensive nature of nanomaterials technology requires organizational and managerial innovation. This case study demonstrates a model to enable growth through radical innovation in nanomaterials, while taking advantage of an incumbent firm's capabilities and complementary assets. Organizational strategies include incubation from a risk‐adverse culture, relatively long timelines for evaluation, and a high‐level steering committee. Managerial strategies focus on product development, risk reduction, and active risk management.