This study investigated the feasibility of glassfiber filter coated with titanium dioxide (TiO2) on removing indoor VOCs using photocatalytic technology, which could further expand the electronic filter¡¦s function . First of all, we coated the titanium dioxide (TiO2) photocatalysts on the glassfiber filter with chemical vapor desposition (CVD) method, then dried it at 120¢J, and calcined it to prepare a nano-sized TiO2 coated filter . Secondly, we collected VOC samples in a printery and analyzed their chemical components. The main components of VOCs (benzene¡Btoluene and acetone) were then conducted in a self-designed laboratory-scaled batch photocatalytic reactor. The decomposition of acetone for different operating parameters, including initial VOC concentration, CVD coating time, and calcination temperature, was further conducted. Besides, a nano-sized photocatalyst indoor air purifier was self-designed for this particular study. The air purifier consists of a set of near-UV light source, a nano-sized photocatalyst glassfiber filter, a stainless shelter, and a circulating fan. The air purifier was tested to ascertain its capability on the removal of indoor VOCs in a well-tight environmental chamber. The testing results indicated the nano-sized photocatalyst glassfiber filter can be used to remove indoor VOCs . In the final stage, a nano-sized TiO2 photocatalyst electronic air cleaner was self-designed for this particular further study in a printery. The air cleaner consists of a set of UV light source, a nano-sized photocatalyst glassfiber filter, a set of electronic filter, carborn filter and a pain coated steel plate shelter. The air cleaner was tested to ascertain its capability on the removal of indoor VOCs in a return air channel of air condition system. The testing results indicated that the nano-sized photocatalyst glassfiber filter can be used to remove indoor VOCs

Today, with increasing global awareness and regulation of air pollution, interest in the smog-abating property of photocatalytic materials is increasing. Titanium dioxide (TiO2) is the most well known photocatalytic semiconductor and is often considered as one way of solving pollution by a passive but an effective way, particularly to reduce atmospheric nitrogen oxides (NOx=NO+NO2). This relatively new technology is already being used in some of the countries as a construction material, commercially sold as photocatalytic cement, photocatalytic pavement, self-cleaning tiles, and self-cleaning glass. Prior research has examined the photocatalytic properties of TiO2 itself, as well as TiO2-containing cement-based materials. The majority of this effort has been on characterizing and enhancing the photocatalytic efficiency. However, relatively little research was performed to assess the potential impact of the photocatalytic reaction on the "parent" or "host" material. In this research, the focus is on the effect of photocatalysis on the composition, structure, and properties of cementitious materials, which contain titania nanoparticles at early and late ages. Fundamental examinations on the addition of these chemically non-reactive nanoparticles to cement-based materials are performed. The high surface area of nanoparticles could alter early age properties of cementitious materials, such as setting time, dimensional stability, and hydration rate. Various experimental techniques as well as mathematical modeling were used to examine and explain the early age hydration of cementitious materials when TiO2 nanoparticles are present. Further, the effects of the TiO2 on the long term durability of cement-based materials are investigated to demonstrate their suitability for long-term use in the field. The photocatalytic NOx oxidation efficiency and NOx binding capability of TiO2 containing cementitious materials are experimentally investigated. The durability of TiO2-cement is examined by various techniques on samples that went through extensive photocatalysis and environmental exposures. These investigations have led to tentative conclusions on the use of TiO2 nanoparticles in cementitious materials, and suggest avenues for future study.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Materials Science and Engineering." Includes bibliographical references (p. 164-172).

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 173-183).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 140-151).

The main goal of this research was to develop a mechanism-based model for photocatalytic disinfection of bacteria in water using suspended catalyst pthesiss in batch reactors. The photocatalytic disinfection process occurs as a semiconductor photocatalyst, most commonly titanium dioxide (TiO2), is irradiated with light of wavelength less than 380 nm to produce hydroxyl radicals and other highly reactive oxidants which can inactivate microorganisms. Photocatalytic disinfection involves a complex interaction of many fundamental mechanisms such as light absorption and scattering by semiconductor pthesiss, electrochemical surface reactions, and heterogeneous colloidal stability. Current models, based largely on chemical reacting systems, do not adequately account for these fundamental mechanisms. Even the Langmuir model developed for heterogeneous systems cannot describe the interactions of such large colloidal pthesiss. As a result, it is difficult to assess the combined effects of many important factors which go into the design of a photocatalytic disinfection system. A mechanistic modeling approach is desirable because it provides a framework to understand the influence of many important parameters on the disinfection process. It requires a description of the physical properties of the catalyst, the nature of the suspending electrolyte solution, the physical and chemical properties of the cell surface, and the energetic aspects that influence the interaction of the pthesiss. All these aspects are interrelated. While it is customary to envision the adsorption of reactants unto a catalyst surface, for photocatalytic disinfection involving suspended catalyst pthesiss, multiple catalyst pthesiss adhere to the bacterial surface. In this work a mechanistic model has been developed that simulates the effect of light intensity and catalyst concentration on the disinfection process. The simulations show good agreement with the experimental data for stable colloidal suspensions, that is, suspensions in which rapid aggregation of cells and TiO2 do not occur. Increased disinfection rates and high levels of inactivation can be achieved by maintaining a relatively low catalyst-to-microbe ratio while maximizing the light intensity. The influence of pH and ionic strength on the disinfection process have been included in the model, but these are only expected to be accurately predicted when the solution remains stable.

The Tin dioxide (SnO2) and Titanium dioxide (TiO2) are very promising materials in Material science. The SnO2 is commonly used as a gas sensor while the TiO2 is used as a catalyst in many reactions. Despite of the usefulness of these two substances, their surface structures lack detail investigations in the previous years. The Low Energy Electron Diffraction (LEED) technique is commonly used to characterize surfaces in the past 40 years, it is a mature system that many researches rely on its result. However, structural analysis in LEED requires comparison with computational results based on pre-defined structure models, which is a time-consuming method and the results are not guaranteed to be found. The direct determinations of structure by Patterson function inversion methods introduced by Huasheng Wu and S. Y. Tong could provide a different path to search for surface structure. In the Patterson function, each maximum in the function corresponds to a relative position vector of atomic pairs. Multiple-angle-incident LEED has to be performed to obtain an artifact-free Patterson function. Serveal SnO2 and TiO2 surfaces have been characterized by LEED and Patterson function inversion. SnO2 (110), (100), (101) , Rutile TiO2 (110), Anatase TiO2 (110) have been prepared by argon ion sputtering and annealing cycles and the cleanness has been checked by Auger Electron Spectroscopy and LEED. Reconstruction is observed based on the study of the LEED patterns. SnO2 (110) surface shows a 4 x 1 reconstruction in UHV environment while it gives 1 x 1 under annealing in oxygen and C(2 x 2) at higher annealing temperature afterward. SnO2 (100) , (101) and Rutile TiO2 (110) surfaces show 1 x 1 reconstruction in UHV environment and the reconstruction persists for further annealing. The Anatase TiO2 (110) surface shows a 3 x 4 reconstruction in UHV environment. The 3 x 4 reconstruction of Anatase TiO2 (110) surface would raise research interests as it is quite a special reconstruction. Multiple-angle-incident LEED has been performed on the SnO2 (100), (101) and Rutile TiO2 (110) surfaces. Patterson function inversion is performed on the surfaces SnO2 (100) and Rutile TiO2 (110) . Only LEED is performed on SnO2 (110) , (101) and Anatase TiO2 (110) surfaces. From Patterson functions analysis, the surface atoms positions are determined for the surface SnO2 (100) and Rutile TiO2 (110). The results show that their reconstructions are negligible, but they have obvious relaxations. / published_or_final_version / Physics / Master / Master of Philosophy

Στην εργασία αυτή πραγματοποιήθηκε μια βιβλιογραφική ανασκόπηση σχετικά με τις ευαισθητοποιημένες ηλεκτροχημικές κυψελίδες και τα οργανικά φ/β, τις αρχές λειτουργίας τους,τα υλικά τους και τους τρόπους παρασκευής τους. Παρασκευάσαμε ηλεκτροχημικές κυψελίδες χρησιμοποιώντας διαφορετικές χρωστικές και αντιηλεκτρόδια. Όλες οι κυψελίδες δοκιμάστηκαν κάτω από διαφορετικές συνθήκες για την εύρεση των παραγόντων που επηρεάζουν την απόδοσή τους. Παράγοντες όπως το πάχος και η τραχύτητα του υμενίου, διαφορετικές χρωστικές και αντιηλεκτρόδια κτλ βελτιστοποιήθηκαν για την αύξηση τησ απόδοσης. Επίσης εξετάστηκε η σταθερότητα των κυψελίδων αυτών με το χρόνο. Τέλος εξετάστηκαν και εξηγήθηκαν οι παράγοντες για τη χαμηλή απόδοση των κυψελίδων. / In this study we make a comprehensive literature review on dye-sensitized nanostructured and organic solar cells, their operating principles, materials as well as their manufacturing methods. We have fabricated dye – sensitized electrochemical solar cells using different dyes and counter electrodes. All solar cells were tested under different conditions in order to find the factors limiting their efficiency. Factors like film thickness and roughness, different dyes and counter electrodes etc were changed in order to improve efficiency. The stability of these solar cells were also evaluated for different time intervals. The efficiency was rather low and the reasons for this are examined and explained thorougηly.

Vandenilio, kaip energijos nešėjo gavyba ir saugojimas yra iki šiol neišspręsta problema. Viena iš perspektyvių vandenilio gavybos iš vandens technologijų yra katalitinis vandens skaidymas TiO2 paviršiuje. Šiame darbe nagrinėjama titano dioksido dangų formavimas plazmoje. Plazma formuojama vandens garuose, gauti jonai greitinami elektriniame lauke ir implantuojami į titano tūrį. Tai termodinamiškai nepusiausvyrinis procesas, kurio metu inicijuojama daug kitų procesų, keičiančių medžiagos paviršiaus sudėtį ir struktūrą. Darbe pristatomas fenomenologinis, vienadimensinis plazmos sąveikos su medžiaga modelis, medžiagos paviršinio sluoksnio elementinės sudėties kinetikos modeliavimui. Modelis įvertina keletą vienalaikių medžiagos sąveikos su plazma procesų, tokių kaip joninė implantacija, paviršiaus joninė erozija, adsorbcija, terminė difuzija. Didžiausias dėmesys šiame darbe buvo skiriamas difuzijai ir joninei implantacijai, kaip pagrindiniams masės pernešimo procesams su plazma sąveikaujančios medžiagos tūryje. Buvo pateikta keletas alternatyvių šiuos procesu aprašančių modelių. Darbe pateikiami deguonies koncentracijos profiliai titane, gauti po sąveikos su jonų pluošteliu suformuotu vandens garų plazmoje. Taip pat pateikiamas modelio taikymas šių eksperimentų modeliavimui. Gauti rezultatai taikant skirtingus modelius palyginti tarpusavyje, taip pat su eksperimento rezultatais. / The production and storage of hydrogen as energy carrier is still unsolved problem. One of the most promising hydrogen production technologies is water catalysis reaction on the surface of TiO2. In this work formation of TiO2 films in plasma is studied. Plasma is initiated in water vapour, obtained ions are accelerated in electric field and implanted into the bulk of titanium. It is thermodynamically non-equilibrium process by which many other plasma-material interaction processes occur. The one-dimensional, phenomenological model of ion beam interaction with solids, for the simulation of material surface composition kinetic during the process is presented. Few ion beam–material interaction processes are considered in the model, such as ion implantation, sputtering, adsorption, thermal diffusion. The main attention in this work has been paid to the processes of diffusion and ion implantation, as they are the main mass transport processes. Several alternative models for these processes have been proposed. The experimental oxygen concentration profiles in titanium after irradiation of water vapour plasma are presented. The model has been applied for the simulation of this experiment. Results obtained by different models have been compared.

Šiame darbe apžvelgiama plazmos savybės, jonų ir atomų sąveika su kietų kūnų paviršiais, balistiniai procesai. Aptarti plonų dangų nusodinimo metodai, titano dioksido (TiO2) panaudojimo galimybės ir fotokatalitinis efektas. TiO2 yra plačiai naudojamas pramonėje dėl savo gerų mechaninių, elektrinių ir optinių savybių. Magnetroninis dulkinimas buvo pasirinktas dangų formavimo procese. Darbo tikslas – oksiduoti titano dangas reaktyvioje vandens garų plazmoje naudojant joninio implantavimo technologiją ir paaiškinti deguonies bei vandenilio judėjimo mechanizmą Ti dangose. Bandiniai paveikti skirtingos galios plazma, oksidavimo laikai nevienodi. Prieš ir po sąveikos su plazma dangos analizuotos šiais metodais: SEM, EDS, GDOES, AES, XRD. Pagal gautus rezultatus darbe gilintasi į skirtingo storio dangų oksidavimo mechanizmus. / In this paper plasma properties, ions and atoms interaction with solids is explained as well as ballistic processes. Thin films deposition methods, TiO2 characteristics and photocatalytic effect is discussed. Titanium oxide is widely used in industry for its good mechanical, electrical and optical properties. Physical vapor deposition is a method that enables us to obtain the layers with desirable properties. The aim of this research is to oxidize titanium using water vapor plasma immersion ion implantation (PIII) technology and to develop the mechanism of oxygen and hydrogen transport in Ti film. Samples were fabricated after different power and duration of plasma treatment. All of them have been analyzed by nanoprofilometer, SEM (scanning electron microscopy), EDS (energy dispersive X – ray spectroscopy), AES (Auger electron spectroscopy), GDOES (glow discharge optical emission spectroscopy) and XRD (X – ray diffraction). The oxidation mechanism of Ti films with different thicknesses is discussed on the basis of the obtained experimental results.