Role of Reduced Defects for Coupling Reactions of Acetaldehyde on Anatase TiO2（001）-（1×4） Surface

The chemistry of acetaldehyde (CH3CHO) adsorbed on the anatase TiO2(001)-(1×4) surface has been investigated by temperature-programmed desorption (TPD) method. Our experimental results provide the direct evidence that the perfect lattice sites on the anatase TiO2(001)-(1×4) surface are quite inert for the reaction of CH3CHO, but the reduced defect sites on the surface are active for the thermally driven reductive carbon-carbon coupling reactions of CH3CHO to produce 2-butanone and butene. We propose that the coupling reactions of CH3CHO on the anatase TiO2(001)-(1×4) surface should undergo through the adsorption of paired CH3CHO molecules at the reduced defect sites, since the existing reduced Ti pairs provide the suitable adsorption sites.

Ag-AgBr/TiO_2光催化剂的制备及其降解染料的研究

采用简单的沉积沉淀法制备了Ag-Ag Br/Ti O2复合光催化剂.通过粉末X射线衍射和紫外-可见漫反射表征了催化剂的结构和光学性质.进而,使用X射线光电子能谱验证了Ag-Ag Br/Ti O2表面的Ag物种以Ag(0)和Ag(I)形式存在.研究表明分别在可见光和紫外光照射下液相降解罗丹明B,与单独的Ti O2相比,Ag-Ag Br/Ti O2有更高的光催化活性.此外,还研究了在光催化过程中电子的传输路径.基于表征结果和光催化活性,观察到和讨论了Ag-Ag Br和Ti O2的协同作用.

合成高炉渣中TiO_2还原的发泡特性参数

测定了在不同条件下 ,合成高炉渣中TiO2 被碳还原时泡沫渣高度与时间的关系。由实验数据和改进的计算程序确定了该发泡过程的发泡特性参数 ,实现了对发泡过程进行定量描述。着重分析了初渣中TiC的含量和还原过程产生TiC对发泡过程的影响 ,确定了引起含高TiO2 渣在发泡时产生多次发泡的原因。

rGO改性TiO_2薄膜的制备及光催化性能

氧化石墨烯-二氧化钛(GO-TiO_2)前驱体溶胶经浸渍-提拉成薄膜,再经热处理、紫外辐照还原得到还原氧化石墨烯-二氧化钛(rGO-TiO_2)薄膜.利用XRD、Raman、SEM对薄膜进行表征分析.通过光催化还原Ag+以及光催化降解甲基橙研究GO加入量对rGO-TiO_2薄膜光催化性能的影响;并将光催化还原Ag+后的薄膜直接用于降解甲基橙.结果表明:薄膜中TiO_2的晶相为锐钛矿相与金红石相的混合晶相,GO部分被还原为rGO;薄膜表面平整,片状rGO均匀镶嵌其中;当GO质量分数为1.0%和1.5%时,rGO-TiO_2薄膜的光催化性能接近,光催化还原Ag+的效率为93%左右,光催化降解甲基橙的效率为92%左右;光催化还原Ag+后的薄膜直接用来降解甲基橙,其降解效率明显提高.

TiO_(2-x)纳米粒子薄膜型氧敏元件的性能

以钛酸丁酯和无水乙醇分别为前驱体和溶剂 ,添加适量稳定剂制成稳定溶胶 ,用浸涂法在 Al2 O3基片上制备 Ti O2 薄膜 ,经在 10 0 0℃氢气氛下还原制得 Ti O2 - x薄膜 .通过 SEM照片发现薄膜颗粒在几十纳米左右 ,颗粒分布均匀 .由 XRD分析 ,薄膜的 x值在 0～ 0 .5之间 .实验结果表明 ,Ti O2 - x薄膜在 80 0℃下具有良好的氧敏感性和响应特性 ,薄膜在 N2 条件下具有很好的电阻

Electrochemical Fabrication of rGO-embedded Ag-TiO2 Nanoring/Nanotube Arrays for Plasmonic Solar Water Splitting

Effective utilization of hot electrons generated from the decay of surface plasmon resonance in metal nanoparticles is conductive to improve solar water splitting efficiency.Herein,Ag nanoparticles and reduced graphene oxide(rGO)co-decorated hierarchical TiO2 nanoring/nanotube arrays(TiO2 R/T)were facilely fabricated by using two-step electrochemical anodization,electrodeposition,and photoreduction methods.Comparative studies were conducted to elucidate the effects of rGO and Ag on the morphology,photoresponse,charge transfer,and photoelectric properties of TiO2.Firstly,scanning electron microscope images confirm that the Ag nanoparticles adhered on TiO2 R/T and TiO2 R/T-rGO have similar diameter of 20 nm except for TiO2 R-rGO/T.Then,the UV-Vis DRS and scatter spectra reveal that the optical property of the Ag-TiO2 R/T-rGO ternary composite is enhanced,ascribing to the visible light absorption of plasmonic Ag nanoparticles and the weakening effect of rGO on light scattering.Meanwhile,intensity-modulated photocurrent spectroscopy and photoluminescence spectra demonstrate that rGO can promote the hot electrons transfer from Ag nanoparticles to Ti substrate,reducing the photogenerated electron-hole recombination.Finally,Ag-TiO2 R/T-rGO photoanode exhibits high photocurrent density(0.98 mA cm?2)and photovoltage(0.90 V),and the stable H2 evolution rate of 413μL h?1 cm?2 within 1.5 h under AM 1.5 which exceeds by 1.30 times than that of pristine TiO2 R/T.In line with the above results,this work provides a reliable route synergizing rGO with plasmonic metal nanoparticles for photocatalysis,in which,rGO presents a broad absorption spectrum and effective photogenerated electrons transfer.

w(TiO2)对高铬型钒钛磁铁矿烧结矿冶金性能的影响

以高铬型钒钛磁铁矿和普通磁铁矿精矿混合料为原料,通过烧结杯试验考察了TiO2质量分数对高铬型钒钛磁铁矿烧结矿性能的影响规律.研究结果表明:随着TiO2质量分数从6.30%增加到11.76%,转鼓指数逐渐降低,烧结矿强度降低,垂直烧结速度、成品率和烧结杯利用系数均呈现上升的趋势;直径小于5 mm的小粒径烧结矿的比例逐渐降低,粒度有增大的趋势;随着TiO2质量分数的增加,赤铁矿含量降低,磁铁矿含量增加,同时,钙钛矿和Fe9TiO15相也增加.低温还原粉化指数有上升的趋势,相反还原性降低.

String and Ball-Like TiO_2/rGO Composites with High Photo-catalysis Degradation Capability for Methylene Blue

Novelthree-dimensionalstring and ball-like titanium dioxide/reduced graphene oxide, TiO_2/rGO(STG) composites were prepared using a one-step hydrolysis process followed by a low-temperature hydrothermaltreatment. The STG composites exhibited excellent photo-catalytic degradation performance for methylene blue owing to a good synergistic effect between TiO_2 and rGO. The STG composites with 1.0 wt% of rGO loading exhibited the highest removalrate of 86.0% for methylene blue and its reaction rate constant(5.27 × 10^(-3) min^(-1)) was much higher than those of pure string and ball-like TiO_2(ST). In addition, the STG composites also showed an outstanding capability for the photo-catalysis degradation of other cationic dyes. In addition, a possible photo-catalytic degradation mechanism for the STG composite was postulated, in which~?O_2^- and~·OH were the main oxidizing groups. This work of fers new insights into a better design and preparation of novelcomposite materials for the removalof organic dyes.

Ionic Liquid-Assisted One-Step Hydrothermal Synthesis of TiO2-Reduced Graphene Oxide Composites

We have demonstrated a facile and efficient strategy for the fabrication of soluble reduced graphene oxide sheets （RGO） and the preparation of titanium oxide （TiO2） nanoparticle-RGO composites using a modified one-step hydrothermal method. It was found that graphene oxide could be easily reduced under solvothermal conditions with ascorbic acid as reductant, with concomitant growth of TiO2 particles on the RGO surface. The TiO2-RGO composite has been thoroughly characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Microscopy techniques （scanning electron microscopy, atomic force microscopy, and transmission electron microscopy） have been employed to probe the morphological characteristics as well as to investigate the exfoliation of RGO sheets. The TiOR-RGO composite exhibited excellent photocatalysis of hydrogen evolution.

Aqueous-Phase Synthesis ofAg-TiO2-Reduced Graphene Oxide and Pt-TiO2-Reduced Graphene Oxide Hybrid Nanostructures and Their Catalytic Properties

We demonstrate an aqueous solution method for the synthesis of a Ag-TiO2-reduced graphene oxide （rGO） hybrid nanostructure （NS） in which the Ag and TiO2 particles are well dispersed on the rGO sheet. The Ag-TiO2-rGO NS was then used as a template to synthesize Pt-TiO2-rGO NS. The resulting hybrid NSs were characterized by transmission electron microscopy （TEM）, high-resolution TEM （HRTEM）, energy-dispersive X-ray （EDX） spectroscopy, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, Fourier transform infrared （FTIR） spectroscopy, UV-vis spectroscopy, Raman spectroscopy, inductively coupled plasma mass spectrometry （ICP-MS）, and catalytic studies. It was found that TiO2-rGO, Ag-TiO2-rGO and Pt-TiO2-rGO NSs all show catalytic activity for the reduction of p-nitrophenol to p-aminophenol by NaBH4, and that Pt-TiO2-rGO NS exhibits the highest catalytic activity as well as excellent stability and easy recyclability.

Synthesis of Biphasic Defective TiO2-x/Reduced Graphene Oxide Nanocomposites with Highly Enhanced Photocatalytic Activity

Biphasic defective TiO2-x/reduced graphene oxide（RGO） nanocomposites were synthesized by simple hydrothermal reactions. Compared with TiO2-x and commercial P25, TiO2-x/RGO shows much better photocatalytic activity and excellent stability in pollutants degradation, which could be ascribed to Ti^3＋ centers complexed with RGO and the synergetic effect between the two phases. The study reveals a new route for the synthesis of mixed-phase defective TiO2-x/carbon material nanocomposites for photocatalytic applications.

Effect of Ce doping into V_(2)O_(5)-WO_(3)/TiO_(2) catalysts on the selective catalytic reduction of NO_(x) by NH_(3)

In this work, the effectiveness of V2O5-WO3/TiO2 catalysts modified with different CeO2 contents by impregnation and co-precipitation methods on the selective catalytic reduction of NOxby NH3 have been studied comparatively by various experimental techniques. The results showed that the NO conversion of V2O5-WO3/CeO2-TiO2 catalysts modified by co-precipitation method obviously increased with the Ce doping contents in the studied range below 20%（All Ce contents are in mass fractions）, but the NO conversion of V2O5-WO3/CeO2/TiO2 catalysts modified by impregnation methods was lower than V2O5-WO3/CeO2-TiO2 catalysts especially beyond 2.5% Ce doping contents. The V2O5-WO3/CeO2-TiO2 catalysts showed better SCR activity, wider reaction window, and higher sulfur and water resistance. The characterization results elucidated that the modified catalysts by co-precipitation method exhibited higher specific surface area, much better dispersity of Ce component, more Ce^（3＋）species and more Br？nsted acid sites than that by impregnation. The vacancies caused by more Ce^（3＋）species were favorable for more NO oxidation to NO2, and the interaction between Ce species and WOxspecies generated more Br？nsted acid sites. It could be supposed that dispersed Ce Oxspecies and WOxspecies offered more second active centers respectively to adsorb oxygen and activate ammonia as co-catalysis to the primary active center of V ions, thus facilitated the better SCR activity of modified V2O5-WO3/CeO2-TiO2 catalysts by coprecipitation methods. The co-precipitation methods with Ce component were more suitable for production of modified commercial V2O5-WO3/TiO2 catalysts.

Synthesis of a nitrogen-doped titanium dioxide-reduced graphene oxide nanocomposite for photocatalysis under visible light irradiation

A nitrogen-doped titanium dioxide-reduced graphene oxide (N-TiO2-RGO)nanocomposite has been synthesized by the combination of a hydrothermal method and a thermal treatment under a NH3/N2 atmosphere.The resulting composites are characterized by Fourier transform infrared spectroscopy, scanning electron microscopy,transmission electron microscopy,diffuse reflectance absorption spectroscopy,energy-dispersive X-ray spectroscopy,and Raman characterization techniques.The sequence of the thermal treatment and hydrothermal treatment processes is shown to influence the photocatalytic activity of nitrogen-doped composites.The composites synthesized by using this method show better photocatalytic activities toward the degradation of acetaldehyde under visible light irradiation compared with P25,N-TiO2,and TiO2-RGO.By applying the thermal treatment process after the hydrothermal pro- cess,nitrogen atoms can be simultaneously doped in the lattice ofTiO2nanoparticles and on the surface of reduced graphene oxide sheets.The conversion of acetaldehyde,as the model molecule of volatile organic compounds,is measured in a continuous stirred-tank reactor until the steady state condition is reached. The conversion of 50 ppm acetaldehyde,in an air flow under illumination from an 80W Hg lamp with a UV cut-off filter,reaches 62% after a 1-h reaction using a 0.07g N-TiO2-RGO sample with an optimum loading of 2wt% graphene oxide.In comparison,the photocatalytic activity of P25 for the degradation of acetaldehyde under visible light irradiation is only 8% under the same reaction conditions.The reaction rates for acetaldehyde degradation are calculated and predicted with pseudo-first-order reaction kinetics,and the activity result of the best N-TiO2-RGO sample is 12.3times higher than for P25.

ASBR法处理酸性钛白废水的技术研究

采用厌氧序批式反应器 (ASBR)处理高浓度硫酸盐废水 ,取得了较好的效果 模拟废水和实际钛白粉废水的试验显示 ,硫酸根离子的去除率分别达到 92 .1% ,83.5 % COD SO42 -的比值对硫酸根离子去除率有较大影响 ,比值在 2～ 3时效果最佳 该试验工艺的一个特点是采用了气循环与水循环并用的方法 ,以防止硫化氢气体对硫酸盐还原菌 (SRB)的毒害 。

Ag–AgBr/TiO_2/RGO nanocomposite:Synthesis,characterization,photocatalytic activity and aggregation evaluation

Ag-AgBr/TiO2 supported on reduced graphene oxide （Ag-AgBr/TiO2/RGO） with different mass ratios of grapheme oxide （GO） to TiO2 were synthesized via a facile solvothermal-photo reduction method. Compared to the single-, two- and three-component nanocomposites, the four-component nanocomposite, Ag-AgBr/TiO2/RGO-1 with mass ratio of GO to TiO2 at 1%, exhibited a much higher photocatalytic activity for the degradation of penicillin G （PG） under white light-emitting diode （LED-W） irradiation. The PG degradation efficiency increased with the increase of mass ratio of GO to TiO2 from 0.2% to 1%, then it decreased with the increase of mass ratio of GO to TiO2 from 1% to 5%. The zeta potentials of RGO-nanocornposites became more negative with the presence of humic acid （HA） due to the negatively charged HA adsorption, resulting in the shift of points of zero charge to lower values of pH. The aggregations of nanocomposites were more significant due to the bridging effect of HA. Furthermore, the aggregated particle sizes were larger for ROO-nanocomposites compared to other nanoparticles, due to the bindings of the carboxylic and phenolic functional groups in HA with the oxygen-containing functional groups in the RGO-nanocomposites. The microfiltration （MF） membrane was effective for the nanocomposites separation. In the continuous flow through submerged membrane photoreactor （sMPR） system, backwashing operation could efficiently reduce membrane fouling and recover TiO2, and thus indirectly facilitate the PG removal.

Chemical deactivation of V2Os-WO3/Ti02 SCR catalyst by combined effect of potassium and chloride

V2O5-WO3/WiO2 catalyst was poisoned by impregnation with NHaC1, KOH and KC1 solution, respectively. The catalysts were characterized by X-ray diffraction （XRD）, inductively coupled plasma （ICP）, N2 physisorption, Raman, UV-vis, NH3 adsorption, temperature-programmed reduction of hydrogen （H2- TPR）, temperature-programmed oxidation of ammonia （NH3-TPO） and selective catalytic reduction of NOx with ammonia （NH3-SCR）. The deactivation effects of poison- ing agents follow the sequence of KC1 〉 KOH 〉〉 NH4CI. The addition of ammonia chloride enlarges the pore size of the titania support, and promotes the formation of highly dispersed V = O vanadyl which improves the oxidation of ammonia and the high-temperature SCR activity. K~ ions are suggested to interact with vanadium and tungsten species chemically, resulting in a poor redox property of catalyst. More importantly, potassium can reduce the Bronsted acidity of catalysts and decrease the stability of Bronsted acid sites significantly. The more severe deactivation of the KCl-treated catalyst can be mainly ascribed to the higher amount of potassium resided on catalyst.

Enhanced photocatalytic activity of rGO/TiO2 for the decomposition of formaldehyde under visible light irradiation

Due to the low concentration of indoor air contaminants, photocatalytic technology shows low efficiency for indoor air purification. The application of TiO2 for photocatalytic removal of formaldehyde is limited, because TiO2 can only absorb ultraviolet （UV） light. Immobilization of TiO2 nanoparticles on the surface of graphene can improve the visible light photocatalytic activity and the adsorption capacity. In this study, rGO （reduced graphene oxide）/TiO2 was synthesized through a hydrotherrnal method using titanium tetrabutoxide and graphene oxide as precursors, and was used for the degradation of low concentration formaldehyde in indoor air under visible light illumination. Characterization of the crystalline structure and morphology of rGO/TiO2 revealed that most GO was reduced to rGO during the hydrothermal treatment, and anatase TiO2 nanoparticles （with particle size of 15-30 nm） were dispersed well on the surface of the rGO sheets, rGO/TiO2 exhibited excellent photocatalyfic activity for degradation of formaldehyde in indoor air and this can be attributed to the role ofrGO, which can act as the electron sink and transporter for separating photo-generated electron-hole pairs through interfacial charge transfer. Furthermore, rGO could adsorb formaldehyde molecules from air to produce a high concentration of formaldehyde on the surface of rGO/ TiO2. Under visible light irradiation for 240 min, the concentration of formaldehyde could be reduced to 58.5 ppbV. rGO/TiO2 showed excellent moisture-resistance behavior, and after five cycles, rGO/TiO2 maintained high photocatalytic activity for the removal of formaldehyde （84.6%）. This work suggests that the synthesized rGO/TiO2 is a promising photocatalyst for indoor formaldehyde removal.

Novel Pd/TiO2-Al2O3 Catalysts for Methane Total Oxidation at Low Temperature and Their ^18O-Isotope Exchange Behavior

Pd supported on TiO2-Al2O3 binary oxides prepared by coprecipitation method has been investigated for the total oxidation of methane. All Pd/TiO2-Al2O3 catalysts show higher activity than Pd/Al2O3 and Pd/TiO2. Among them, Pd/2Ti-3Al with a Ti/Al ratio of 2 to 3 has a T90% of 395 ℃ at a gas hourly mass velocity of 33000 mL/（h＊g）, which is at least 50 ℃ lower than that of Pd supported on single metal oxide Al2O3 or TiO2. The results of TPR and ^180-isotope exchange experiments demonstrated that the excellent activity of Pd/2Ti-3Al was due to its high oxygen mobility and moderate reducibility, which is in accordance with our previous work, XPS results indicated that the dispersion of Pd was not the key factor to influence the catalytic activity.

Multi-dimensionally ordered, multi-functionally integrated r-GO@TiO2（B）@Mn304 yolk-membranc shell superstructures for ultrafast lithium storage

TiO2（B） is an attractive new anode candidate for lithium-ion batteries （LIBs） due to its unique and highly desirable properties, including high structural integrity, long cycle life, and low cost. However, despite these merits, its inherent slow lithium and electron transport kinetics hinder its practical application to LIBs. Here, we propose a novel, simple route towards multi-dimensionally ordered, multi-functionally integrated reduced graphene oxide （r-GO）@TiO2（B）@Mn304 yolk-membrane-shell superstructures in which r-GO nanosheets, TiO2（B） nanosheets, and Mn304 nanoparticles are hierarchically organized to achieve remarkable synergistic interactions. This hybridization design is fundamentally bilateral in nature, aiming to overcome the conductivity and capacity deficiencies of TiO2（B） simultaneously. The resulting r-GO@TiO2（B）@Mn304 yolk-membrane- shell superstructures have great potential as advanced anode materials for ultrafast lithium storage, delivering a strikingly high reversible capacity of 662 mA.h-g-1 at 500 mA-g^-1 after 500 charge-discharge cycles.

Enhanced Efficiency of Dye-sensitized Solar Cells Using rGO@TiO2 Nanotube Hybrids

We established a novel strategy for the synthesis of reduced graphene oxide（rGO）@TiO2 nanotube hybrids using an 18 W UV-assisted photo-catalytic reduction method for utilization as photo-anode of dye-sensitized solar cells（DSSCs）. The photo-conversion efficiency of DSSCs was significantly enhanced after the addition of rGO, and in addition, the photo-anode showed decreased internal resistance. Analysis of rGO@TiO2 hybrids by transmissions scanning electron microscopy（TEM）, X-ray diffraction（XRD）, Raman spectra, N2 adsorption and desorption, atomic force microscopy（AFM） and X-ray photoelectron speetroscopy（XPS） demonstrates that the rGO modified TiO2 nanotubes can increase the short-circuit current and the conversion efficiency of dye-sensitized solar cells. The efficiency is improved by almost two folds as much compared to those of the bare TiO2 nanotubes.