DOCSLIB.ORG

Photoinduced Adsorption and Oxidation of SO2 on Anatase Tio2(101) ̈ David Langhammer, Jolla Kullgren, and Lars Osterlund*

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Photoinduced Adsorption and Oxidation of SO2 on Anatase Tio2(101) ̈ David Langhammer, Jolla Kullgren, and Lars Osterlund* This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. pubs.acs.org/JACS Article Photoinduced Adsorption and Oxidation of SO2 on Anatase TiO2(101) ̈ David Langhammer, Jolla Kullgren, and Lars Osterlund* Cite This: J. Am. Chem. Soc. 2020, 142, 21767−21774 Read Online ACCESS Metrics & More Article Recommendations *sı Supporting Information ABSTRACT: Adsorption of molecules is a fundamental step in all heterogeneous catalytic reactions. Nevertheless, the basic mechanism by which photon-mediated adsorption processes occur on solid surfaces is poorly understood, mainly because they involve excited catalyst states that complicate the analysis. Here we demonstrate a method by which density functional theory (DFT) can be used to quantify photoinduced adsorption processes on transition metal oxides and reveal the fundamental nature of these reactions. fi Speci cally, the photoadsorption of SO2 on TiO2(101) has been investigated by using a combination of DFT and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The combined experimental and theoretical approach gives a detailed description of the photocatalytic desulfurization process on TiO2,in fi 2− which sulfate forms as a stable surface product that is known to poison the catalytic surface. This work identi es surface-SO4 as the sulfate species responsible for the surface poisoning and shows how this product can be obtained from a stepwise oxidation of SO − 2 on TiO2(101). Initially, the molecule binds to a lattice O2 ion through a photomediated adsorption process and forms surface fi 2− sul te, which is subsequently oxidized into surface-SO4 by transfer of a neutral oxygen from an adsorbed O2 molecule. The work further explains how the infrared spectra associated with this oxidation product change during interactions with water and surface hydroxyl groups, which can be used as fingerprints for the surface reactions. The approach outlined here can be generalized to other photo- and electrocatalytic transition metal oxide systems. ■ INTRODUCTION adsorption has gained attention recently because of the technologically important superwetting properties of UV Adsorption of molecules on surfaces is the fundamental step 13,14 Downloaded via 5.241.82.182 on January 4, 2021 at 18:05:30 (UTC). preluding all heterogeneous catalytic reactions. Such adsorp- irradiated TiO2 surfaces. tion processes are well understood during thermally activated Because photoadsorption plays an important role during 1−5 catalytic reactions, but corresponding insights into photo- photocatalytic reactions involving O2 and hydroxyls, it is activated adsorption processes are much less developed,1 albeit reasonable that it should also be important in other − experimentally well established.6 8 The dominant view of photostimulated surface reactions. During artificial photosyn- See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles. photoadsorption on metal oxide photocatalysts is that thesis by CO2 reduction, adsorption of CO2 and subsequent − molecular oxygen or surface cations capture photoexcited formation of CO2 under photoillumination are considered to 15 electrons, while holes are captured by hydroxyls from be crucial reaction steps. On TiO2(001), CO2 forms surface- 2− 2− 16,17 dissociated water molecules or surface oxygen atoms. This CO3 by bonding to a lattice O ion, and it has been 2− separation of excited charges is crucial for the overall shown that an accumulation of CO3 species at the surface is ffi − fi photocatalytic e ciency, since recombination of electron associated with the deactivation of TiO2 during arti cial hole pairs otherwise occurs on a much faster time scale than photosynthesis, which typically occurs within a few hours.18 the surface chemical reactions.9 On titania (TiO ), which is by 2 Similarly, the TiO2 surface becomes deactivated during NOx far the most well-studied photocatalyst due to its large oxidation when surface-NO − (Ti−O−NO −) and/or ad- abundance and high stability, excited electrons are readily 3 2 captured by O2 molecules, while the holes are localized at terminal OH− groups that form upon dissociative adsorption Received: September 9, 2020 − • Published: December 17, 2020 of H2O. This leads to the formation of O2 and OH , which together have an oxidative potential exceeding 3 eV (290 kJ/ mol). In particular, photoadsorption of O2 has attracted considerable interest, stemming back to works by Bickley et 10,11 12 al. and Boonstra and Mutsaers, while H2O photo- © 2020 American Chemical Society https://dx.doi.org/10.1021/jacs.0c09683 21767 J. Am. Chem. Soc. 2020, 142, 21767−21774 Journal of the American Chemical Society pubs.acs.org/JACS Article − 19−21 37 sorbed NO3 (ads) is formed. During photocatalytic value used in this work has been suggested by Selloni et al. oxidation of SO2, 98% of the reacted SO2 molecules are based on a linear response analysis using a defective anatase fi converted into strongly bound sulfate species that deactivate TiO2(101) slab. To localize added electrons at speci c Ti sites, the surface completely in <30 min, such that the surface must the titanium atoms were slightly displaced prior to the ionic be regenerated either by heating above 400 °C or by dissolving relaxation, such that local potential energy minima were the sulfate ions in aqueous solutions.22 The latter approach is obtained after relaxation on Ti4+ ions, which thereby were the simplest and most effective (provided that the pH is kept reduced to Ti3+. The assignment of the Ti3+ ions was made neutral), although sulfur poisoning still remains a large issue based on their characteristic magnetization (close to unity) and 22,23 during oxidative desulfurization on TiO2. Several reaction by inspecting the spin-density charge distribution. The mechanisms have been suggested to explain the transformation titanium, oxygen, and sulfur atoms were treated by using 4, 24−27 of SO2 into sulfate on TiO2, including formation of 6, and 6 valence electrons, respectively, and pseudopotentials 2− surface-SO4 through interaction with lattice oxygen and have been generated by using the projected augmented wave 2− − formation of SO4 (ads) by reactions with surface hydroxyls. It (PAW) method to account for the valence core interactions, has also been suggested that oxygen vacancies are the main as suggested by Blöchl et al.38 A plane wave basis set with a reactive adsorption sites,28 although this assertion was shown kinetic energy cutoff of 546 eV has been used to model the to be incorrect in our previous study.29 In previous studies we electronic wave functions, and all calculations have been Γ have shown that SO2 does not adsorb in the absence of UV performed at the -point only inside the Brillouin zone. illumination on crystalline and stoichiometric TiO2 at room The anatase TiO2(101) surface was modeled by using a total temperature, employing identical particles as those used in this of 192 atoms in a slab consisting of 64 TiO2 units, building a 29,30 × work. These conclusions are qualitatively supported by the (2 3) supercell with four stoichiometric TiO2 layers. The work of Baltrusaitis et al.,24 showing much larger adsorption slabs were separated by a vacuum gap of more than 15 Å. Ionic capacity on small 4 nm TiO2 nanoparticles compared to 32 nm relaxations were performed until all forces were <0.01 eV/Å by nanocrystals. Therefore, SO2 adsorption on anatase TiO2 using a conjugant gradient algorithm. Vibrational frequencies provides a good example of how excited-state chemistries were calculated by using the finite differences method facilitate molecule adsorption. implemented in VASP, that is, by displacing a selected number In this work, we simulate the photocatalytic formation of of atoms in the direction of each Cartesian coordinate to 2− surface-SO4 on TiO2(101) by localizing negative charge determine the Hessian matrix (step size 0.015 Å). Only atoms around the SO2 adsorbate. This generally describes the that were part of the adsorbate and the surface atoms situation during interband absorption in strongly correlated coordinating with the adsorbate were allowed to move during metal oxides, where excited electrons usually localize on this displacement. The calculated frequencies have been shifted ν − ν surface metal cations. The localization of charge on Ti in TiO2 by 0.08 22.159, where is the wavenumber. This relation enables the formation of a strong covalent bond between sulfur was obtained by plotting the difference between calculated 2− 2− and lattice O , such that a surface-SO3 adsorbate is formed. frequencies of molecular SO2 and the experimental gas phase 2− This acts as an intermediate during formation surface-SO4 by frequencies as a function of the wavenumber. asubsequentoxidationinvolving an adsorbed oxygen molecule. This photoadsorption mechanism can be understood ■ EXPERIMENT as a concerted activation of lattice oxygen and neighboring In situ diffuse reflectance infrared Fourier transform spectroscopy titanium, which should be generally valid for other adsorbate (DRIFTS) measurements have been performed to monitor the photo- systems, such as H2O, CO2,NO2, and so on, as well as other oxidation of SO2 on anatase TiO2 nanoparticles and to study the ff transition d- or f-metal oxides. It is thus also relevant in studies e ect of a subsequent exposure to H2O. Measurements were − of geochemical reactions involving mineral dust particles.31 33 performed on a vacuum-pumped FTIR spectrometer (Vertex 80v, Bruker Optik GmbH, Ettlingen, Germany) equipped with a custom Importantly, our results present a simple mechanism by which fi photoadsorption processes can be simulated and quantified by modi ed Praying Mantis high-temperature reaction chamber (HVC- DRM-5, Harrick Inc., USA), which enabled gas flow through the using density functional theory (DFT). To add further support fi powder sample bed and simultaneous IR and UV illumination of the to these ndings, dedicated experiments have been performed sample during measurements.
Load more

Recommended publications
  • Enhanced Heterogeneous Uptake of Sulfur Dioxide on Mineral Particles Through Modification of Iron Speciation During Simulated Cloud Processing
    Atmos. Chem. Phys., 19, 12569–12585, 2019 https://doi.org/10.5194/acp-19-12569-2019 © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License. Enhanced heterogeneous uptake of sulfur dioxide on mineral particles through modification of iron speciation during simulated cloud processing Zhenzhen Wang1, Tao Wang1, Hongbo Fu1,2,3, Liwu Zhang1, Mingjin Tang4, Christian George5, Vicki H. Grassian6, and Jianmin Chen1 1Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Institute of Atmospheric Sciences, Fudan University, Shanghai, 200433, China 2Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China 3Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), Nanjing University of Information Science and Technology, Nanjing 210044, China 4State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China 5University of Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, 69626, Villeurbanne, France 6Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA Correspondence: Hongbo Fu ([email protected]) and Jianmin Chen ([email protected]) Received: 7 May 2019 – Discussion started: 5 June 2019 Revised: 7 August 2019 – Accepted: 5 September 2019 – Published: 9 October
    [Show full text]
  • Source Test Method ST-20 SULFUR DIOXIDE, SULFUR TRIOXIDE
    Source Test Method ST-20 SULFUR DIOXIDE, SULFUR TRIOXIDE, SULFURIC ACID MIST (Adopted January 20, 1982) REF: Regulations 6-320, 6-330, 9-1-302, 9-1-304 thru 310, 10-1-301, 12-6-301 1. APPLICABILITY 1.1 This method is used to quantify emissions of s ulfur dioxide, sulfur trioxide and sulfuric acid mist. It determines compliance with Regulations 6-320 and 6-330 for SULFUR TRIOXIDE and SULFURIC ACID MIST, and 9-1-302, 9- 1-304 thru 310 and 10-1-301 and 12-6-301 for SULFUR DIOXIDE. 1.2 This method, modified with a glass fiber disc filter as the back-up SO 3 filter, has been given alternate status by the EPA to EPA Method 8. It may be used to determine compliance with oxides of sulfur regulations under Regulation 9. 2. PRINCIPLE 2.1 Sulfuric acid mist, sulfur trioxide and sulfur dioxide are collected in a single extractive sampling train. Acid mist is trapped in a quartz wool plug in the sample probe and is subsequently analyzed with an acid-base titration. Sulfur trioxide is absorbed in an 80% isopropyl alcohol (IPA)/water solution with a quartz wool back-up filter and is analyzed using analytical procedure Lab-12. Sulfur dioxide is absorbed in an aqueous hydrogen peroxide solution and is analyzed using analytical procedure Lab-12. 3. RANGE 3.1 The minimum measurable concentration using this method listed below are: 3 3.1.1 Acid mist - 0.0002 gr/ft as H2SO4 3.1.2 Sulfur trioxide - 7 ppm 3.1.3 Sulfur dioxide - 7 ppm 3.2 The maximum measurable concentrations using this method listed below are: 3.2.1 Acid mist - undetermined 3.2.2 Sulfur trioxide - 350 ppm 3.2.3 Sulfur dioxide - 2.5 % 4.
    [Show full text]
  • SO2 Removal by NH3 Gas Injection: Effects of Temperature and Moisture Content
    Ind. Eng. Chem. Res. 1994,33, 1231-1236 1231 SO2 Removal by NH3 Gas Injection: Effects of Temperature and Moisture Content Hsunling Bai' Institute of Environmental Engineering, National Chiao- Tung University, Hsin-Chu, Taiwan, R.O.C. Pratim Biswas and Tim C. Keener Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, Ohio 45221 -0071 The removal of SO2 by NH3 gas injection at various temperatures and moisture contents has been studied experimentally. The product compositions of the NH3-SO2-HzO vapor reactions were also reported. A thermodynamic analysis was carried out to predict the SO2 removal as well as the product compositions. Both the experimental results and thermodynamic analysis indicated that SO2 removal and the product compositions are sensitive to the reaction temperature. Moisture content, once in large excess of the stoichiometric requirement, does not have a strong effect on the product compositions but plays an important role in the SO2 removal. Introduction conditions. Stromberger (1984) used X-ray diffraction and identified the product particles to be (NH&S04 Sulfur dioxide removal from flue gases is a goal of many crystals. air pollution engineers. Significant efforts in the develop- ment of new flue gas desulfurization (FGD) technologies Although a number of studies on the removal of SO2 are being made. Major processes related to FGD tech- from flue gases by NH3 injection have been conducted, nologies include water scrubbing, metal ion solutions, there is disagreement on the operating condition (such as catalytic oxidation, dry or semidry adsorption, wet lime temperature) that a high removal efficiency can be or limestone scrubbing, double alkali process, and ammonia obtained.
    [Show full text]
  • The Role of Titanium Dioxide on the Hydration of Portland Cement: a Combined NMR and Ultrasonic Study
    molecules Article The Role of Titanium Dioxide on the Hydration of Portland Cement: A Combined NMR and Ultrasonic Study George Diamantopoulos 1,2 , Marios Katsiotis 2, Michael Fardis 2, Ioannis Karatasios 2 , Saeed Alhassan 3, Marina Karagianni 2 , George Papavassiliou 2 and Jamal Hassan 1,* 1 Department of Physics, Khalifa University, Abu Dhabi 127788, UAE; [email protected] 2 Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310 Aghia Paraskevi, Attikis, Greece; [email protected] (M.K.); [email protected] (M.F.); [email protected] (I.K.); [email protected] (M.K.); [email protected] (G.P.) 3 Department of Chemical Engineering, Khalifa University, Abu Dhabi 127788, UAE; [email protected] * Correspondence: [email protected] Academic Editor: Igor Serša Received: 30 September 2020; Accepted: 9 November 2020; Published: 17 November 2020 Abstract: Titanium dioxide (TiO2) is an excellent photocatalytic material that imparts biocidal, self-cleaning and smog-abating functionalities when added to cement-based materials. The presence of TiO2 influences the hydration process of cement and the development of its internal structure. In this article, the hydration process and development of a pore network of cement pastes containing different ratios of TiO2 were studied using two noninvasive techniques (ultrasonic and NMR). Ultrasonic results show that the addition of TiO2 enhances the mechanical properties of cement paste during early-age hydration, while an opposite behavior is observed at later hydration stages. Calorimetry and NMR spin–lattice relaxation time T1 results indicated an enhancement of the early hydration reaction.
    [Show full text]
  • Nanosized Particles of Titanium Dioxide Specifically Increase the Efficency of Conventional Polymerase Chain Reaction
    Digest Journal of Nanomaterials and Biostructures Vol. 8, No. 4, October - December 2013, p. 1435 - 1445 NANOSIZED PARTICLES OF TITANIUM DIOXIDE SPECIFICALLY INCREASE THE EFFICENCY OF CONVENTIONAL POLYMERASE CHAIN REACTION GOVINDA LENKA, WEN-HUI WENG* Department of Chemical Engineering and Biotechnology, Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of Technology, Taipei 10608, Taiwan, R. O. C. In recent years, the use of nanoparticles (NPs) for improving the specificity and efficiency of the polymerase chain reaction (PCR) and exploring the PCR enhancing mechanism has come under intense scrutiny. In this study, the effect of titanium dioxide (TiO2) NPs in improving the efficiency of different PCR assays was evaluated. Transmission electron microscopy (TEM) results revealed the average diameter of TiO2 particles to be about 7 nm. Aqueous suspension of TiO2 NPs was included in PCR, reverse transcription PCR (RT-PCR) and quantitative real time PCR (qPCR) assays. For conventional PCR, the results showed that in the presence of 0.2 nM of TiO2 a significant amount of target DNA (P<0.05) could be obtained even with the less initial template concentration. Relative to the larger TiO2 particles (25 nm) used in a previous study, the smaller TiO2 particles (7 nm) used in our study increased the yield of PCR by three or more fold. Sequencing results revealed that TiO2 assisted PCR had similar fidelity to that of a conventional PCR system. Contrary to expectation, TiO2 NPs were unable to enhance the efficiency of RT- PCR and qPCR. Therefore, TiO2 NPs may be used as efficient additives to improve the conventional PCR system.
    [Show full text]
  • Properties of Thermally Evaporated Titanium Dioxide As an Electron-Selective Contact for Silicon Solar Cells
    energies Article Properties of Thermally eVaporated Titanium Dioxide as an Electron-Selective Contact for Silicon Solar Cells Changhyun Lee 1, Soohyun Bae 1, HyunJung Park 1, Dongjin Choi 1, Hoyoung Song 1, Hyunju Lee 2, Yoshio Ohshita 2, Donghwan Kim 1,3, Yoonmook Kang 3,* and Hae-Seok Lee 3,* 1 Department of Materials Science and Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea; [email protected] (C.L.); [email protected] (S.B.); [email protected] (H.P.); [email protected] (D.C.); [email protected] (H.S.); [email protected] (D.K.) 2 Semiconductor Laboratory, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya 468-8511, Japan; [email protected] (H.L.); [email protected] (Y.O.) 3 KU-KIST Green School, Graduate School of Energy and Environment, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea * Correspondence: [email protected] (Y.K.); [email protected] (H.-S.L.) Received: 6 January 2020; Accepted: 23 January 2020; Published: 5 February 2020 Abstract: Recently, titanium oxide has been widely investigated as a carrier-selective contact material for silicon solar cells. Herein, titanium oxide films were fabricated via simple deposition methods involving thermal eVaporation and oxidation. This study focuses on characterizing an electron-selective passivated contact layer with this oxidized method. Subsequently, the SiO2/TiO2 stack was examined using high-resolution transmission electron microscopy. The phase and chemical composition of the titanium oxide films were analyzed using X-ray diffraction and X-ray photoelectron spectroscopy, respectively.
    [Show full text]
  • TITANIUM DIOXIDE Chemical and Technical Assessment First Draft
    TITANIUM DIOXIDE Chemical and Technical Assessment First draft prepared by Paul M. Kuznesof, Ph.D. Reviewed by M.V. Rao, Ph.D. 1. Summary Titanium dioxide (INS no. 171; CAS no. 13463-67-7) is produced either in the anatase or rutile crystal form. Most titanium dioxide in the anatase form is produced as a white powder, whereas various rutile grades are often off-white and can even exhibit a slight colour, depending on the physical form, which affects light reflectance. Titanium dioxide may be coated with small amounts of alumina and silica to improve technological properties. Commercial titanium dioxide pigment is produced by either the sulfate process or the chloride process. The principal raw materials for manufacturing titanium dioxide include ilmenite (FeO/TiO2), naturally occurring rutile, or titanium slag. Both anatase and rutile forms of titanium dioxide can be produced by the sulfate process, whereas the chloride process yields the rutile form. Titanium dioxide can be prepared at a high level of purity. Specifications for food use currently contain a minimum purity assay of 99.0%. Titanium dioxide is the most widely used white pigment in products such as paints, coatings, plastics, paper, inks, fibres, and food and cosmetics because of its brightness and high refractive index (> 2.4), which determines the degree of opacity that a material confers to the host matrix. When combined with other colours, soft pastel shades can be achieved. The high refractive index, surpassed by few other materials, allows titanium dioxide to be used at relatively low levels to achieve its technical effect. The food applications of titanium dioxide are broad.
    [Show full text]
  • The Chemical Behaviors of Nitrogen Dioxide Absorption in Sulfite Solution
    Article The Chemical Behaviors of Nitrogen Dioxide Absorption in Sulfite Solution Ye Sun, Xiaowei Hong, Tianle Zhu *, Xiaoyan Guo and Deyuan Xie School of Space and Environment, Beihang University, Beijing 100191, China; [email protected] (Y.S.); [email protected] (X.H.); [email protected] (X.G.); [email protected] (D.X.) * Correspondence: [email protected]; Tel.: +86-10-8231-4215 Academic Editor: Agustín Bueno López Received: 14 March 2017; Accepted: 6 April 2017; Published: 12 April 2017 Abstract: The simultaneous removal of nitrogen oxides (NOx) and sulfur dioxide (SO2) by absorption is considered to be one of the most promising technologies for flue gas treatment, and sulfite is the main component of the absorption solution. To understand the chemical behaviors of the NO2 absorption in sulfite solution, the absorption time dependences of concentrations of nitrogen and sulfur compositions in both gas phase and liquid phases were investigated by flue gas analyzer, Ion chromatography (IC), Gas chromatography (GC), and Fourier transform infrared spectrometry (FTIR) methods using a bubbling reactor. The mass equilibrium of the N and S compositions were also studied. The results indicate that sulfite concentration plays a vital role in NO2 absorption. The main absorption products are NO3− and NO2−, and NO2− can be converted into NO3− in the presence of oxygen. Besides, about 4% to 9% by-products of S compositions are formed, and 4% to 11% by-products of N compositions such as NO, N2, N2O5, N2O, and HNO3 in the gas phase were detected in the emissions from the bubbling reactor. On the basis of N and S compositions, a possible pathway of NO2 absorption in sulfite solution was proposed.
    [Show full text]
  • Structural Aspects of Anatase to Rutile Phase Transition in Titanium Dioxide Powders Elucidated by The
    Chapter 3 Structural Aspects of Anatase to Rutile Phase Transition in Titanium Dioxide Powders Elucidated by the Rietveld Method Alberto Adriano Cavalheiro, Lincoln Carlos Silva de Oliveira and Silvanice Aparecida Lopes dos Santos Additional information is available at the end of the chapter http://dx.doi.org/10.5772/intechopen.68601 Abstract Titanium dioxide has attracted much attention since a long time ago due to its versatility as advanced material. However, its performance as semiconductor devices is very much dependent on the predominant crystalline phase and defect concentrations, which can be adjusted through the synthesis methods, thermal treatments and doping processes. In this work, an accurate structural characterization of titanium dioxide was used by X-ray diffractometry supported by rietveld refinement and thermal analysis. The insertion of 5 mol% of zirconium silicate was able to stabilize anatase up to 900C, permitting the oxygen vacancies to be significantly eliminated. It was demonstrated also that the changes in the isotropic thermal parameters for oxygen are related to reconstructive transformation necessary to promote the anatase-to-rutile phase transition. Independently of doping process, the crystallization process of anatase phase as a function of temperature increas- ing occurs exclusively due the reduction of lattice microstrain up to 600C. However, above 650C, that crystallization process becomes dependent of the increasing in crystallite size. The anatase crystallite growth event was only possible when the titanium dioxide was doped with zirconium silicate. Otherwise, the rutile phase amount starts to rise continually. Thus, there are optimistic expectations for that new composition to be a new semiconductor matrix for additional doping processes.
    [Show full text]
  • Recent Advances in Tio2-Based Photocatalysts for Reduction of CO2 to Fuels
    nanomaterials Review Recent Advances in TiO2-Based Photocatalysts for Reduction of CO2 to Fuels 1,2, 3, 4 5 Thang Phan Nguyen y, Dang Le Tri Nguyen y , Van-Huy Nguyen , Thu-Ha Le , Dai-Viet N. Vo 6 , Quang Thang Trinh 7 , Sa-Rang Bae 8, Sang Youn Chae 9,* , Soo Young Kim 8,* and Quyet Van Le 3,* 1 Laboratory of Advanced Materials Chemistry, Advanced Institute of Materials Science, Ton Duc Thang University, Ho Chi Minh City 700000, Vietnam; [email protected] 2 Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City 700000, Vietnam 3 Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam; [email protected] 4 Key Laboratory of Advanced Materials for Energy and Environmental Applications, Lac Hong University, Bien Hoa 810000, Vietnam; [email protected] 5 Faculty of Materials Technology, Ho Chi Minh City University of Technology (HCMUT), Vietnam National University–Ho Chi Minh City (VNU–HCM), 268 Ly Thuong Kiet, District 10, Ho Chi Minh City 700000, Vietnam; [email protected] 6 Center of Excellence for Green Energy and Environmental Nanomaterials (CE@GrEEN), Nguyen Tat Thanh University, 300A Nguyen Tat Thanh, District 4, Ho Chi Minh City 755414, Vietnam; [email protected] 7 Cambridge Centre for Advanced Research and Education in Singapore (CARES), Campus for Research Excellence and Technological Enterprise (CREATE), 1 Create Way, Singapore 138602, Singapore; [email protected] 8 Department of Materials Science and Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea; [email protected] 9 Department of Materials Science, Institute for Surface Science and Corrosion, University of Erlangen-Nuremberg, Martensstrasse 7, 91058 Erlangen, Germany * Correspondence: [email protected] (S.Y.C.); [email protected] (S.Y.K.); [email protected] (Q.V.L.); Tel.: +42-01520-2145321 (S.Y.C.); +82-109-3650-910 (S.Y.K.); +84-344-176-848 (Q.V.L.) These authors contributed equally to this work.
    [Show full text]
  • UCLA Electronic Theses and Dissertations
    UCLA UCLA Electronic Theses and Dissertations Title Electrochemical Performance of Titanium Disulfide and Molybdenum Disulfide Nanoplatelets Permalink https://escholarship.org/uc/item/73h6h1z6 Author Siordia, Andrew F. Publication Date 2016 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA Los Angeles Electrochemical Performance of Titanium Disulfide and Molybdenum Disulfide Nanoplatelets A thesis submitted in partial satisfaction of the requirements of the degree Master of Science in Materials Science and Engineering by Andrew Francisco Siordia 2016 ABSTRACT OF THESIS Electrochemical Performance of Titanium Disulfide and Molybdenum Disulfide Nanoplatelets by Andrew Francisco Siordia Master of Science in Materials Science and Engineering University of California, Los Angeles, 2016 Professor Bruce S. Dunn, Chair Single layer crystalline materials, often termed two-dimension (2D) materials, have quickly become a popular topic of research interest due to their extraordinary properties. The intrinsic electrical, mechanical, and optical properties of graphene were found to be remarkably distinct from graphite, its bulk counterpart. In conjunction with newfound processing techniques, there is renewed interest in elucidating the structure-property relationships of other 2D materials ii like the transition metal dichalcogenides (TMDCs). The energy storage capability of 2D nanoplatelets of TiS2 and MoS2 are studied here providing a contrast with investigations of corresponding bulk materials in the early 1970s. TiS2 was synthesized into nanoplatelets using a hot injection route which provided a capacity of ~143mAhg-1 from thin film electrodes as determined by cyclic voltammetry measurements. Phase identification using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy to complement the electrochemical performance and impurity identification is presented.
    [Show full text]
  • Potential Ivvs.Gelbasedre
    US010644304B2 ( 12 ) United States Patent ( 10 ) Patent No.: US 10,644,304 B2 Ein - Eli et al. (45 ) Date of Patent : May 5 , 2020 (54 ) METHOD FOR PASSIVE METAL (58 ) Field of Classification Search ACTIVATION AND USES THEREOF ??? C25D 5/54 ; C25D 3/665 ; C25D 5/34 ; ( 71) Applicant: Technion Research & Development HO1M 4/134 ; HOTM 4/366 ; HO1M 4/628 ; Foundation Limited , Haifa ( IL ) (Continued ) ( 72 ) Inventors : Yair Ein - Eli , Haifa ( IL ) ; Danny (56 ) References Cited Gelman , Haifa ( IL ) ; Boris Shvartsev , Haifa ( IL ) ; Alexander Kraytsberg , U.S. PATENT DOCUMENTS Yokneam ( IL ) 3,635,765 A 1/1972 Greenberg 3,650,834 A 3/1972 Buzzelli ( 73 ) Assignee : Technion Research & Development Foundation Limited , Haifa ( IL ) (Continued ) ( * ) Notice : Subject to any disclaimer , the term of this FOREIGN PATENT DOCUMENTS patent is extended or adjusted under 35 CN 1408031 4/2003 U.S.C. 154 ( b ) by 56 days . EP 1983078 10/2008 (21 ) Appl. No .: 15 /300,359 ( Continued ) ( 22 ) PCT Filed : Mar. 31 , 2015 OTHER PUBLICATIONS (86 ) PCT No .: PCT/ IL2015 /050350 Hagiwara et al. in ( Acidic 1 - ethyl - 3 -methylimidazoliuum fluoride: a new room temperature ionic liquid in Journal of Fluorine Chem $ 371 (c ) ( 1 ), istry vol . 99 ( 1999 ) p . 1-3 ; ( Year: 1999 ). * (2 ) Date : Sep. 29 , 2016 (Continued ) (87 ) PCT Pub . No .: WO2015 / 151099 Primary Examiner — Jonathan G Jelsma PCT Pub . Date : Oct. 8 , 2015 Assistant Examiner Omar M Kekia (65 ) Prior Publication Data (57 ) ABSTRACT US 2017/0179464 A1 Jun . 22 , 2017 Disclosed is a method for activating a surface of metals , Related U.S. Application Data such as self- passivated metals , and of metal -oxide dissolu tion , effected using a fluoroanion -containing composition .
    [Show full text]