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Effect of yttrium on catalytic performance of Y-doped TiO_(2) catalysts for propane dehydrogenation

Journal of Rare Earths 2024年第5期42卷 962-971,I0005页

作者： Liyu Hou Liming Xia Ruipeng Zhou Jianmei Li Renjie Li Zhen Zhao Guimei Yuan Aijun Duan State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China Institute of Catalysis for Energy and Environment College of Chemistry and Chemical EngineeringShenyang Normal UniversityShenyang110034China

Defective bulk catalysts based on TiO_(2) have superior catalytic performance for propane dehydrogenation(PDH).The oxygen vacancy concentration and the number of active sites on the catalyst surface can be effectively tuned by doping metal in TiO_(2).Herein,yttrium(Y)-doped titanium dioxide(nY/TiO_(x))catalysts were in-situ synthesized via the coprecipitation method to study the effect of rare earth metal Y doping on the structure of TiO_(2) and the catalytic performance for PDH.Experimental results demonstrate that Ydoped TiO_(2) exhibits higher catalytic activity,propylene selectivity and stability than bare TiO_(2).Full characterizations with X-ray diffraction(XRD),high-resolution transmission electron microscope(HRTEM),X-ray photoelectron spectroscopy(XPS),infrared spectroscopy of pyridine adsorption(Py-IR),temperature-programmed desorption of ammonia(NH_(3)-TPD),H_(2) temperature-programmed reduction(H_2-TPR),and Raman techniques on these catalysts reveal that Y^(3+)can enter TiO_(2) lattice,and the lattice stability of the catalyst can be enhanced by replacing Ti^(4+)to form Y-O-Ti structure.Meanwhile,the introduction of an appropriate amount of Y can obviously promote the PDH reaction by adjusting the acidity of the catalyst,improving the release capacity of TiO_(2) lattice oxygen and increasing the formation of active centers.Nevertheless,excessive Y doping will lead to pore clogging,and the exposure of active sites will be reduced,resulting in the degradation of catalytic performance.

关键词： Propane dehydrogenation anatase Lattice defects Coordinatively unsaturated Ti cations Oxygen vacancy Rare earths

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The storage mechanism difference between amorphous and anatase as supercapacitors

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Green Energy & Environment 2022年第1期7卷 156-164页

作者： Wanggang Zhang Yiming Liu Zhiyuan Song Changwan Zhuang Aili Wei College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuanShanxi030024China Shanxi Academy of Analytical Sciences TaiyuanShanxi030006China

Although TiO_(2)nanotubes is a promising electrode as supercapacitors due to its high energy density,easy synthesis and chemical stability,there are draw backs such as low conductivity and capacitance.Many studies concentrated on improving its electrochemical performance itself but little attention was payed to the reason of capacitance differences caused by its different crystal structures.Herein,we prepare amorphous and anatase TiO_(2)nanotubes and hydrogenated them by a simple electrochemical hydrogenation method to improve their conductivity and capacitance.And then study and compare their morphology and structure differences by SEM,TEM,XRD and BET.The results show that the pore size distribution,internal structure order and internal carrier concentration are the main reasons for their electrochemical performance differences.The microporous structure less than 2 nm in amorphous nanotubes act as a trap of electrolyte ions at current density larger than 0.1μA cm^(-2),leading to small charge and discharge capacitance.The long-range ordered crystal structure of anatase is more favorable for the orderly diffusion of carriers,reducing the inelastic scattering of carrier diffusion process and the electron hole-complexing probability,making anatase nanotubes exhibit higher coulomb efficiency and cycle stability than that of amorphous ones.

关键词： Electrochemical hydrogenation TiO_(2)nanotube arrays Amorphous anatase Super capacitor

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anatase/Bronze TiO2 Heterojunction:Enhanced Photocatalysis and Prospect in Photothermal Catalysis

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Chemical Research in Chinese Universities 2020年第6期36卷 992-999页

作者： WANG Changhua ZHANG Xintong Key Laboratory for UV-Emitting Materials and Technology of Ministry of Education Northeast Normal University Changchun 130024P.R.China

TiO2 heterojunction with different TiO2 phases has been widely adopted for enhanced photocatalysis.Therein,a less common anatase/bronze TiOz heterojunction,also named as anatase/TiO2(B)heterojunction,has recently drawn increasing interest.In this review,the structural advantages of anatase/bronze TiO2 heterojunction for enhanced photocatalysis is highlighted in terms of less lattice mismatch and better charge separation at the interface.Besides photocatalysis,the anatase/bronze TiO2 heterojunction is proven a promising candidate for heat-assisted photocatalysis,named as photothermal catalysis.Further,the anatase/bronze TiO2 heterojunction can serve as a good model to evaluate the strategy for improved photocatalysis and even photothermal catalysis.Herein,the recent attempts on boosting the photocatalytic and photothermal catalytic performance of anatase/bronze TiO2 heterojunction are summarized.It is expected that this review would arouse renewed interest for revisiting TiO2 heterojunction in photocatalysis,photothermal catalysis and other advanced photocatalysis.

关键词： anatase Bronze Photocatalysis Photothermal catalysis

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A simple and novel synthetic route to prepare anatase TiO2 nanopowders from natural ilmenite via the H3PO4/NH3 process

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International Journal of Minerals,Metallurgy and Materials 2020年第6期27卷 846-855页

作者： Lalinda Palliyaguru Ushan S.Kulathunga Lakruwani I.Jayarathna Champa D.Jayaweera Pradeep M.Jayaweera Department of Chemistry University of Sri JayewardenepuraNugegoda-10250Sri Lanka

A simple and novel technique for the preparation of anatase TiO2 nanopowders using natural ilmenite(FeTiO3)as the starting material is reported.Digesting ilmenite with concentrated H3PO4 under refluxing conditions yields a whiteα-titanium bismonohydrogen orthophosphate monohydrate(TOP),Ti(HPO4)2·H2O,which can be easily isolated via gravity separation from unreacted ilmenite.The addition of ammonia to the separated TOP followed by calcination at 500°C completes the preparation of anatase TiO2.Calcination at temperatures above 800°C converts the anatase form of TiO2 to the stable rutile phase.The removal of iron from ilmenite during the commercial production of synthetic TiO2 is problematic and environmentally unfriendly.In the present study,the removal of iron was found to be markedly simple due to the high solubility of iron phosphate species in concentrated H3PO4 with the precipitation of TOP.The titanium content of the prepared samples on metal basis with silica and phosphorous as major impurities was over 90%.Prepared TiO2 samples were characterized using X-ray fluorescence,Fourier-transform infrared spectroscopy,Raman spectroscopy,ultraviolet–visible diffuse reflectance spectroscopy,high-resolution transmission electron microscopy,and X-ray diffraction analyses.The photocatalytic potentials of the commercial and as-prepared TiO2 samples were assessed by the photodegradation of rhodamine B dye.

关键词： ilmenite phosphoric acid titanium phosphates titanium dioxide anatase rutile

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Active Sites for Adsorption and Reaction of Molecules on Rutile TiO2(110) and anatase TiO2(001) Surfaces

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Chinese Journal of Chemical Physics 2015年第4期28卷 -页

作者： Shi-jing Tan Bing Wang Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China Hefei 230026 China

The reactivity of specific sites on rutile TiO2(110)−(1×1) surface and anatase TiO2(001)−(1×4) surface has been comparably studied by means of high resolution scanning tunneling microscopy. At the rutile TiO2(110)−(1×1) surface, we find the defects of oxygen vacancy provide distinct reactivity for O2 and CO2 adsorption, while the terminal fivefold-coordinated Ti sites dominate the photocatalytic reactivity for H2O and CH3OH dissociation. At the anatase TiO2(001)−(1×4) surface, the sixfold-coordinated terminal Ti sites at the oxidized surface seem to be inert in both O2 and H2O reactions, but the Ti-rich defects which introduce the Ti3+ state into the reduced surface are found to provide high reactivity for the reactions of O2 and H2O. By comparing the reactions on both rutile and anatase surfaces under similar experimental conditions, we find the reactivity of anatase TiO2(001) is actually lower than rutile TiO2(110), which challenges the conventional knowledge that the anatase (001) is the most reactive TiO2 surface. Our findings could provide atomic level insights into the mechanisms of TiO2 based catalytic and photocatalytic chemical reactions.

关键词： TiO_2 Rutile anatase Photocatalysis Scanning tunneling microscopy

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Preparation of 3D ordered mesoporous anatase TiO2 and their photocatalytic activity

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Rare Metals 2019年第5期38卷 453-458页

作者： Hui-Li Tang Yu Ren Shun-Hang Wei Gang Liu Xiao-Xiang Xu Shanghai Research Institute of Materials Shanghai 200437China Clinical and Central Lab Putuo People's HospitalTongji University1291 Jiangning RoadShanghai 200060China Shanghai BDS Trading Consultancy Co.Ltd. Shanghai 200433China Shanghai Key Laboratory of Chemical Assessment and Sustainability Department of ChemistryTongji UniversityShanghai 200092China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of ScienceShenyang 110016China School of Materials Science and Engineering University of Science and Technology of China72 Wenhua RoadShenyang 110016China Department of Materials Engineering Huzhou UniversityHuzhou 313000China

Ordered crystalline mesoporous anatase titanium dioxides with different amounts of rutile were prepared by hard-template approaches using mesoporous silica(KIT-6)as the template.The resulting mesoporous materials were characterized by powder X-ray diffraction(PXRD),transmission electron microscope(TEM),N2 adsorption and Raman spectroscopy.All mesoporous TiO2 has three-dimensional(3D)ordered mesostructures with large Brunauer–Emmett–Teller(BET)surface area and narrow pore size distribution(ca.5 nm).It was found that the level of rutile phase in the mesoporous titanium oxide was related to the SO4^2-concentration in the starting materials.Their photocatalytic hydrogen production was evaluated and compared.It is found that low rutile content is beneficial for a high catalytic activity.All samples demonstrate a better activity than commercial P25.

关键词： Mesoporous anatase Rutile Photocatalysis Oxalic acid

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Effect of Yb_2O_3 Additive on Transformation Behavior of anatase for TiO_2/(O′+β′)-Sialon Multi phase Ceramics

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Journal of Rare Earths 2005年第6期23卷 710-715页

作者：杨建薛向欣王文忠王梅丘泰 School of Materials and Metallurgy Northeastern University Shenyang 110004 China College of Materials Science and Engineering Nanjing University of Technology Nanjing 210009 China College

TiO2/（O＇＋ β＇）-Sialon multiphase ceramics were prepared with nano TiO2 （anatase） powder and （O＇＋ β＇）-Sialon powder as raw materials. Effect of Yb2O3 additive on transformation behavior of anatase for TiO2/（O＇＋ β＇）-Sialon multi phase ceramic was investigated and its influence mechanism was discussed. XRD was employed for the analysis of phase composition and lattice parameters. The results show that even though Yb2O3 has no obvious influence on starting temperature of phase transformation, it significantly accelerates the transformation process, which displays a weakened effect with more Yb2O3 addition. There exist two forms of the added Yb2O3 ： some enters TiO2 lattice and the other deposits on the surface of TiO2. The function of Yb2O3 on phase transformation of anatase can be attributed to the coaction of active and negative influence mechanisms as follows： some Yb^n＋ enter TiO2 lattice and replace Ti^4＋ , as well as the redox reaction between Yb^3＋ and TiO2, which promote the transformation, whereas other Yb2O3 deposits on the surface of TiO2, and Ti- O-Yb bond is formed by the coaction of Yb^3＋ and TiO2, which inhibit the process.

关键词： inorganic nonmetallic materials anatase phase transformation Yb2O3 mechanism rare earths

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Vanadium-doped TiO_(2)-B/anatase mesoporous nanotubes with improved rate and cycle performance for rechargeable lithium and sodium batteries

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Journal of Materials Science & Technology 2020年第19期54卷 181-189页

作者： D.P.Opra S.V.Gnedenkov A.A.Sokolov A.B.Podgorbunsky A.Yu.Ustinov V.Yu.Mayorov V.G.Kuryavyi S.L.Sinebryukhova Institute of Chemistry FEB RAS 159Pr.100-letiya Vladivostok1Vladivostok 690022Russia Far Eastern Federal University 8St.Sukhanov1Vladivostok 690950Russia

TiO_(2)-B/anatase nanotubes doped by vanadium have been synthesized through a facile one-step hydrothermal reaction.The material shows a mesoporous structure with a specific surface area of 179.1 m^(2)g^(-1).XPS data presume the presence of V^(3+),V^(4+),V^(5+),and Ti^(3+) in doped TiO2-B/anatase.As found by XRD and EIS investigations,the vanadium expands bronze titania crystal structure and enhances the conductivity of material by three orders of magnitude.When tested for lithium storage,the V-modified titania nanotubes show a specific capacity of 133 mA h g^(-1) after 100 charge/discharge cycles at the current density of 3000 mA g^(-1) with a Coulombic efficiency of around 98.9%,resulting in its good cycleability.The material still possesses a reversible capacity of 114 mA h g^(-1) at a very high current load of 6000 mA g^(-1),demonstrating superior rate characteristics for secondary lithium batteries.Furthermore,V-doped Ti O2-B/anatase mesoporous nanotubes show promise performance as anode material for sodium-ion batteries,delivering about 119 mA h g^(-1) and 101 m A h g^(-1) at the current loads of 10 and 1500 m A g^(-1),respectively.

关键词： Lithium-ion battery Sodium-ion battery Anode TiO_(2)-B anatase Doping Nanotubes Mesoporosity

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Hierarchical-structure anatase TiO2 with conductive network for high-rate and high-loading lithium-ion battery

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Science Bulletin 2019年第16期64卷 1148-1151页

作者： Xinghua Liu Lijiang Zhao Shitong Wang Meng Chao Yutong Li Jin Leng Junying Zhang Zilong Tang Key Laboratory of Micro–nano Measurement Manipulation and Physics(Ministry of Education)School of PhysicsBeihang UniversityBeijing 100191China Department of Nuclear Science and Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Titanium dioxides have been extensively investigated as promising anodes for Lithium ion batteries(LIBs)because of the high–rate capacity and cyclability,as well as the improved safety over graphite anode(1,2)However,as a typical insertion–type anode,anatase TiO2 exhibits low conductivity(10–12S cm-1 for electron conductivity[3]and 10–17–10–10 cm2 s1 for Li+ion diffusion coefficient[4])and poor specific capacity(only accommodate<0.5 Li per bulk TiO2 unit[5]),severely limiting its practical applications.

关键词： TiO Hierarchical-structure anatase TiO2 with conductive network for high-rate and high-loading lithium-ion battery

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A novel synthesis process of ETS-4 titanosilicate using commercial anatase in the absence of fluoride ions

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International Journal of Minerals,Metallurgy and Materials 2012年第8期19卷 675-678页

作者： Li-ying Liu Wen-jun Tan Penny Xiao Yu-chun Zhai School of Materials and Metallurgy Northeastem University Shenyang 110819 China Department of Chemical Engineering Monash university Wellington Road Clayton VIC 3800 Australia Northeastern Research Academy Northeastern University Shenyang 110819 China

A novel synthesis process for ETS-4 titanosilicate using commercial anatase as the titanium source in the absence of fluoride ions was studied. Fluoride ions and traced ETS-4 seeds have important roles in forming ETS-4 structures. However, the method using ETS-4 seeds instead of fluoride ions to improve product purity and productivity is environment-friendly. ETS-4, ETS-4（NS）, and ETS-4（NaF） were respectively synthesized using traced ETS-4 seeds, without seeds, and with fluoride ions. The as-synthesized samples were identified by X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. Adsorption isotherms and adsorption heats of nitrogen and methane on the prepared ETS-4 were also measured. The results showed that ETS-4 samples could be prepared using anatase in the absence of fluoride ions, with good purity, comparable physicochemical properties, and excellent adsorption properties.

关键词： titanosilicate anatase gas adsorption microporous materials

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