2D/2D WO3/Ag:ZnIn2S4 Z型异质结复合物的构筑及可见光催化性能

构筑Z型异质结复合物是光催化领域解决电子-空穴对复合较快的常用方法,其独特的双光子体系能高效的提升光催化速率而备受关注。本文通过水热法原位构筑二维/二维(2D/2D)WO₃/Ag:ZnIn₂S₄ Z型异质结复合物,并且利用透射电子显微镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、紫外-可见漫反射光谱(UV-Vis DRS)、光电化学(PEC)和荧光光谱(PL)对其微观形貌、物相结构、元素化学态和光电性能等进行表征分析,以及采用可见光(加λ>420 nm的滤光片)照射来评价2D/2D WO₃/Ag:ZnIn₂S₄ Z型异质结复合物光解水制氢气和光降解甲基橙(MO)的催化性能。结果表明,在2D/2D WO₃/Ag:ZnIn₂S₄ Z型异质结复合物中,随着Ag:ZnIn₂S₄的含量增加,光催化性能也显著增强。当Ag:ZnIn₂S₄的质量分数为35.0%时,复合物表现出最佳的制氢速率(158.93 μmol.g_-1^.h_-1⁾与降解速率(0.18 min_-1^),这为基于WO₃纳米片设计和构筑2D/2D Z型异质结复合物用于可见光催化制氢和污染物降解提供了新的见解。     

双模板法CeO2/g-C3N4形貌结构特征及湿式催化性能

利用微波辅助双模板法、软模板法制备了一系列的CeO₂/g-C₃N₄复合催化材料,通过XRD、N₂吸附-脱附、XPS、SEM和TEM等方式对材料进行表征,并对其湿式催化性能进行研究。结果表明,双模板法制备的D-CeO₂/g-C₃N₄复合材料表现出立方相CeO₂和层叠g-C₃N₄的特征,比表面积和孔径较大,属于介孔结构,表面存在Ce^₃₊和Ce^₄₊,有利于氧空位的形成。加入1 g嵌段共聚物 F127,使用无水乙醇溶液为溶剂,调节混合液呈碱性,微波辐射反应120 min后得到的D-CeO₂/g-C₃N₄(7.5)样品,结构完整均匀,具有最佳形貌特征。控制反应温度75 ℃,D-CeO₂/g-C₃N₄(7.5)投加0.7 g,H₂O₂投加 0.5 mL,初始pH值为5时,100 mg/L的苯酚溶液COD去除率可达80%以上。 D-CeO₂/g-C₃N₄(7.5) 复合催化材料使用五次以后仍可达60%以上的催化降解效果。     

基于WO3-MoO3和TiO2/CdS复合电极的光电致变色器件

电致变色广泛应用于智能窗领域,但电致变色材料仍需外部电源驱动,将太阳能电池与电致变色材料结合起来的光电致变色器件可实现无需外部供电的智能变色调控。性能优异的变色阴极和光阳极是当下光电致变色器件的研究热点。通过水热法制备WO₃-MoO₃薄膜,研究其电致变色性能;通过水热法结合连续离子层沉积法制备TiO₂/CdS复合薄膜,研究其光电转换性能。最后将WO₃-MoO₃薄膜和TiO₂/CdS复合薄膜分别作为光电致变色器件的变色阴极、光阳极构建WO₃/MoO₃-TiO₂/CdS光电致变色器件。WO₃/MoO₃-TiO₂/CdS光电致变色器件具有较大的光学调制范围(630nm处为41.99%)、更高的着色效率(35.787%),将其作为智能窗应用在现代建筑、通行工具等领域具有重要应用价值。     

测试——聚乙烯亚胺改性磁性膨润土对Pb2+和Cu2+的吸附性能(测试稿件)

在磁性膨润土(MBent)表面接枝聚乙烯亚胺(PEI)制备了聚乙烯亚胺改性磁性膨润土(PEI/KH560/MBent),采用FTIR、VSM、XRD、TGA、EA、SEM和EDS对其进行了表征,考察了其对水溶液中Pb_²⁺和Cu_²⁺的吸附性能。结果表明,聚乙烯亚胺已成功接枝于磁性膨润土表面,并有效提高其对Pb_²⁺和Cu_²⁺吸附量；溶液初始pH对吸附量影响较大,随着pH的增大,吸附量增加。在pH=5,溶液初始质量浓度为300 mg/L,PEI/KH560/MBent对Pb_²⁺和Cu_²⁺吸附量分别为96.21和61.08 mg/g；吸附过程符合准二级动力学模型,吸附行为符合Langmuir吸附等温模型。热力学研究表明,吸附为自发吸热过程。经过5次循环利用后,其吸附容量仍保持初始的60%以上,表明PEI/KH560/MBent具有一定的重复利用性。     

Zn-Al共掺和形貌调控制备LiMn2O4正极材料及电化学性能

采用固相燃烧法和不同的焙烧温度制备了600、650、700和750 ℃的LiZn_0.05Al_0.03Mn_1.92O₄材料。实验结果表明,Zn-Al复合掺杂和焙烧未改变LiMn₂O₄的晶体结构,样品结晶性随焙烧温度的升高而增加,650 ℃及以上时形成了较多包含高暴露{111}、小面积{110}和{100}晶面的截断八面体形貌晶粒,但750 ℃时部分样品发生分解。优化焙烧温度650 ℃的样品具有优良的倍率容量和容量保持率,在5 C和10 C下,初始放电比容量和1000次循环后容量保持率分别为101.3 mAh/g、81.5%和99.9 mAh/g、74.3%。CV和EIS表明,其具有较好的循环可逆性和较大的Li₊^{扩散系数。}Zn-Al共掺和形貌调控改性LiMn₂O₄正极材料有效抑制了LiMn₂O₄材料的Jahn-Teller效应,形成的截断八面体颗粒形貌降低了Mn的溶解,同时提供了更多的Li₊^{迁移三维通道},改善了材料的倍率容量及循环寿命。     

NiPd/TiO2催化剂的制备及其催化甲酸分解制氢性能

高效、清洁且无毒无害的催化剂是实现以甲酸(HCOOH)为化学储氢材料分解制氢的重点。本文采用水热法在453K的条件下制备TiO₂载体,再通过浸渍法向其中加入总量为0.1 mmol的NiCl₂.6H₂O和K₂PdCl₄金属溶液,将活性组分Ni、Pd负载到TiO₂载体上合成NiPd/TiO₂催化剂,并探究其对催化甲酸分解制氢的性能的影响。探究结果表明,在光照条件下,NiPd/TiO₂催化剂中,当金属Ni:Pd比例为2:8时,催化剂的反应转化频率(TOF)值最大,此时催化剂的 TOF 为3528 h_-1^,且该催化剂上甲酸分解的活化能(E_a)为53.9 kJ/mol。关键词：镍钯催化剂;甲酸;分解制氢;二氧化钛;光照中图分类号：TQ630 文献标识码： A 文章编号：     

钢包用矾土尖晶石浇注料的抗渣侵蚀机理研究

利用XRD,SEM等分析手段对用后的以铝酸钙水泥和MgO-SiO₂-H₂O为复合结合剂的钢包矾土尖晶石浇注料进行表征，并对其抗渣侵蚀机理进行研究。分析结果表明：铝酸钙水泥及MgO-SiO₂-H₂O体系的复合结合剂在高温下与基质中矾土细粉、α-Al₂O₃等反应生成非晶态熔融相，使得基质的致密度提高，抑制了钢包渣向其内部的渗透；预合成及原位反应生成的镁铝尖晶石吸附渣中的Fe²⁺，导致渣中Fe²⁺的浓度降低，粘度提高，最终渣的成分转变为硅含量较高的CaO-SiO₂-Al₂O₃渣；矾土原料晶界处杂质在高温下生成的非晶态熔融相迁移至基质，其富含的TiO₂与CaO-SiO₂-Al₂O₃渣中的CaO反应生成稳定的钙钛矿，降低了渣中CaO的含量，渣的粘度进一步提高，抑制了渣向矾土尖晶石浇注料内部的持续渗透和扩散。     

Nd2O3掺杂对MnCoNi系NTC热敏电阻电性能的影响

采用传统固相法制备了Co_0.7-xMn_2.1Ni_0.2Nd_xO₄(X=0,0.04,0.06,0.08)样品。利用X射线衍射、SEM、阻值测量等手段,研究了微量Nd₂O₃掺杂对MnCoNi系NTC热敏电阻材料的影响。研究结果表明：在0≤X≤0.08掺杂范围内,随着Nd₂O₃掺杂量的增加,MnCoNi系NTC热敏电阻的晶相结构和阻温特性并没有改变,晶粒变小,电阻率和B值分别由202.8Ω.cm、3432K,上升到2944.7Ω.cm、4152K;老化特性得到显著提高,△R₂₅/ R₂₅和△B_25/50/ B_25/50变化率分别由1.15%,0.75%降至0.31%,0.22%。     

Cu2O/rGO复合材料修饰阴极强化MFC产电脱氮性能及其机理

微生物燃料电池(MFC)在处理含硝酸盐(NO_3^--N)废水时具有同时产电和脱氮的潜力,寻找成本低且改善其产电脱氮性能的阴极修饰材料是MFC在含氮废水处理领域应用的关键。氧化亚铜/还原氧化石墨烯(Cu₂O/rGO)复合材料具有良好的电化学性能,在替代铂基材料提高MFC性能方面具有一定的应用前景。本研究通过还原法制备了Cu₂O/rGO复合材料,并对材料的结构和氧还原性能进行表征；同时,将其负载于阴极碳布后分析其电化学性能,并通过MFC的输出电压、功率密度和NO_3^--N的去除率探究Cu₂O/rGO阴极对MFC产电和脱氮性能的强化作用；通过对反硝化相关酶活性和胞外聚合物的测定,探究Cu₂O/rGO阴极强化MFC性能的机理。结果表明：Cu₂O/rGO复合材料具有大量的介孔结构,能够为电子传递提供更多的通道,并且Cu₂O/rGO复合材料具有良好的氧化还原可逆性；与Pt/C阴极相比,Cu₂O/rGO阴极的交换电流密度升高33.53%,电子转移阻力降低65.53%；Cu₂O/rGO-MFC在处理NO_3^-N废水时获得的最大平均输出电压(662.54 mV)、最大功率密度(26.27 mW/cm^₂)、平均库伦效率(32.02%)和NO_3^--N去除速率(83.33 mg NO_3^--N L/h)均高于Pt/C-MFC(485.33 mV,16.98 mW/cm^₂,7.38%,41.67 mg NO_3^--N L/h)；Cu₂O/rGO复合材料通过提高MFC阴极反硝化关键酶活性和类蛋白组分含量,改善了MFC的产电和脱氮性能。     

Z型g-C3N4/WO3·H2O的制备与光催化二氧化碳还原性能

利用可见光将CO₂转化为CO和CH₄有望同时解决温室效应和能源危机。Z型光催化体系能够最大限度降低光生电子-空穴对的复合,提高光催化效率。本文采用水热合成法制备了g-C₃N₄/WO₃·H₂O (CNW-1)复合材料,通过X射线衍射、X射线光电子能谱、电镜等方法进行结构表征,探究了298 K、0.1 MPa条件下其对CO₂的可见光催化还原性能,并提出了可能的反应机理。通过调控三氧化钨结晶水含量可以实现CO和CH₄的产量调节,在反应10 h后,CNW-1具有最高的CH₄产率(0.33 μmolg^_-1),而CNW具有最高的CO产率(0.67 μmolg_-1⁾。这项研究为CO₂选择性还原为C1化合物提供了一种有效策略,同时也突出了以g-C₃N₄作为半导体构建Z型光催化体系在催化领域的应用潜力。     

Photocatalytic activity of TiO2 supported on multi-walled carbon nanotubes under simulated solar irradiation

TiO₂ particles supported on multi-walled carbon nanotubes (MWCNTs) were prepared using a sol–gel method to investigate their photocatalytic activity under simulated solar irradiation for the degradation of methyl orange (MO) in aqueous solution. The prepared composites were analyzed using XRD, SEM, EDS and UV–vis absorption spectroscopy. The results of this study indicated that there was little difference in the shape and structure of MWCNTs/TiO₂ composite and pure TiO₂ particles. The composite exhibited enhanced absorption properties in the visible light range compared to pure TiO₂. The degradation of MO by MWCNTs/TiO₂ composite photocatalysts was investigated under irradiation with simulated solar light. The results of this study indicated that MWCNTs played a significant role in improving photocatalytic performance. Different amounts of MWCNTs had different effects on photodegradation efficiency, and the most efficient MO photodegradation was observed for a 2% MWCNT/TiO₂ mass ratio. Photocatalytic reaction kinetics were described using the Langmuir–Hinshelwood (L–H) model. The photocatalyst was reused for eight cycles, and it retained over 95.2% photocatalytic degradation efficiency. Possible decomposition mechanisms were also discussed. The results of this study indicated that photocatalytic reactions with TiO₂ particles supported on MWCNTs under simulated solar light irradiation are feasible and effective for degrading organic dye pollutants.     

Degradation of dye wastewater in a thin-film photoelectrocatalytic (PEC) reactor with slant-placed TiO2/Ti anode

A thin-film photoelectrocatalytic (PEC) reactor with slant-placed TiO₂/Ti anode was developed and successfully applied to degrade Rhodamine B (RhB) and textile effluent. Using a 5–150 mg L⁻¹ RhB solution as the model system, thin-film PEC removed total color and TOC by 99–28% and 78–15%, respectively, in 1 h, which is much higher than 82–7% and 60% to zero by conventional PEC. The enhanced treatment efficiency achieved by thin-film PEC process was attributed to the significantly reduced path length of irradiation light source. The wastewater was kept circulating during the experiments to timely refresh the aqueous film on the TiO₂/Ti anode and promote the mass transfer of the target pollutants and the degradation products in the bulk solution. The thin-film PEC reactor can degrade both simulated and real dye wastewater efficiently under UV light irradiation. Results suggested that thin-film PEC was particularly superior for treating a high concentration solution. The thin-film PEC reactor was also applied to treat RhB solution efficiently under solar light irradiation. The recycle experiments demonstrated excellent stability and reliability of the slant-placed TiO₂/Ti anode. This study proposed a simple and effective method to design PEC reactor applicable for industrial dye wastewater treatment.     

Tungsten and nitrogen co-doped TiO2 nano-powders with strong visible light response

A two-step method, combining with sol–gel and mechanical alloying (MA) method, was used to fabricate the tungsten and nitrogen co-doped TiO₂ nano-powders ((W, N) co-doped TiO₂ NPs). The (W, N) co-doped TiO₂ NPs showed strong absorbance in visible range, as long as 650 nm. Enhanced photocatalytic activities under visible light irradiation were also observed from the results of photodegradation experiments and chemical oxygen demand (COD) analysis. Physical, chemical, and optical properties of the samples were investigated. Possible reasons for the enhanced photocatalytic activities were analyzed based on the experimental results. Oxygen vacancies detected by electron spin response (ESR) spectra, acting as trapping agencies for electrons (e⁻) to produce active oxygen species (O²⁻), were proved to be the main cause for the improved photocatalytic performances.     

Synthesis of Co3O4 Nanoparticles-Decorated Bi12O17Cl2 Hierarchical Microspheres for Enhanced Photocatalytic Degradation of RhB and BPA

Three-dimensional (3D) hierarchical microspheres of Bi₁₂O₁₇Cl₂ (BOC) were prepared via a facile solvothermal method using a binary solvent for the photocatalytic degradation of Rhodamine-B (RhB) and Bisphenol-A (BPA). Co₃O₄ nanoparticles (NPs)-decorated BOC (Co₃O₄/BOC) heterostructures were synthesized to further enhance their photocatalytic performance. The microstructural, morphological, and compositional characterization showed that the BOC microspheres are composed of thin (~20 nm thick) nanosheets with a 3D hierarchical morphology and a high surface area. Compared to the pure BOC photocatalyst, the 20-Co₃O₄/BOC heterostructure showed enhanced degradation efficiency of RhB (97.4%) and BPA (88.4%). The radical trapping experiments confirmed that superoxide (^•O₂⁻) radicals played a primary role in the photocatalytic degradation of RhB and BPA. The enhanced photocatalytic performances of the hierarchical Co₃O₄/BOC heterostructure are attributable to the synergetic effects of the highly specific surface area, the extension of light absorption to the more visible light region, and the suppression of photoexcited electron-hole recombination. Our developed nanocomposites are beneficial for the construction of other bismuth-based compounds and their heterostructure for use in high-performance photocatalytic applications.     

Efficient decomposition of organic compounds with FeTiO3/TiO2 heterojunction under visible light irradiation

FeTiO₃/TiO₂, a new heterojunction-type photocatalyst working at visible light, was prepared by a simple sol–gel method. Not only did FeTiO₃/TiO₂ exhibit greatly enhanced photocatalytic activity in decomposing 2-propanol in gas phase and 4-chlorophenol in aqueous solution, but also it induced efficient mineralization of 2-propanol under visible light irradiation (λ ≥ 420 nm). Furthermore, it showed a good photochemical stability in repeated photocatalytic applications. FeTiO₃ showed a profound absorption over the entire visible range, and its valence band (VB) position is close to that of TiO₂. The unusually high photocatalytic efficiency of the FeTiO₃/TiO₂ composite was therefore deduced to be caused by hole transfer between the VB of FeTiO₃ and TiO₂.     

TiO2 photocatalyst loaded on hydrophobic Si3N4 support for efficient degradation of organics diluted in water

TiO₂ photocatalyst loaded on Si₃N₄ (TiO₂/Si₃N₄) was prepared by a conventional impregnation method and its photocatalytic performance for the degradation of organics (2-propanol) diluted in water was compared with that of TiO₂ photocatalysts (TiO₂/SiO₂, TiO₂/Al₂O₃, and TiO₂/SiC) loaded on various types of supports (SiO₂, Al₂O₃, and SiC). The formation of the well-crystallized anatase phase of TiO₂ was observed on the calcined TiO₂/Si₃N₄ photocatalyst, while a small anatase phase of TiO₂ was observed on the TiO₂/SiC photocatalyst and amorphous TiO₂ species was the main component on the TiO₂/SiO₂ and TiO₂/Al₂O₃ photocatalysts. The measurements of the water adsorption ability of photocatalysts indicated that the TiO₂/Si₃N₄ photocatalyst exhibited more hydrophobic surface properties in comparison to other support photocatalysts. Under UV-light irradiation, the TiO₂/Si₃N₄ photocatalyst decomposed 2-propanol diluted in water into acetone, CO₂, and H₂O, and finally, acetone was also decomposed into CO₂ and H₂O. The TiO₂/Si₃N₄ photocatalyst showed higher photocatalytic activity than TiO₂ photocatalyst loaded on other supports. The well-crystallized TiO₂ phase deposited on Si₃N₄ and the hydrophobic surface of Si₃N₄ support are important factors for the enhancement of photocatalytic activity for the degradation of organic compounds in liquid-phase reactions.     

TiO2-V2O5纳米纤维光催化氧化烟气中的Hg0

对静电纺丝法制备的TiO₂和TiO₂-V₂O₅纳米纤维进行光催化脱除模拟烟气中Hg⁰的研究。对纳米纤维进行了SEM、TEM、XRD、BET和UV-Vis检测。结果表明TiO₂-V₂O₅纳米纤维为锐钛矿,V₂O₅高度分散在TiO₂中。纤维直径在200 nm左右,由粒径为10 nm左右的微粒组成。掺杂V₂O₅后,纤维的吸光范围扩大,在可见光范围内的吸光度比纯TiO₂时有了很大提高。实验研究了不同光照条件、V₂O₅的掺杂量和循环次数对脱汞的影响,分析了TiO₂-V₂O₅催化脱汞的机理。当V₂O₅的质量含量为3%时,TiO₂-V₂O₅在可见光下的脱汞率可达到66%,比纯TiO₂时的7%有了显著提高;纤维的脱汞性能稳定,多次循环后紫外光和可见光下的脱汞率仍分别保持在80%和65%左右。电子的跃迁和电子、空穴的快速分离是TiO₂-V₂O₅在可见光下脱汞率提高的主要原因。     

Photocatalytic degradation of rhodamine B and phenol by solution combustion synthesized BiVO4 photocatalyst

Visible-light-induced BiVO₄ photocatalyst has been successfully synthesized via a solution combustion synthesis (SCS) method. The photocatalytic activities of the as-synthesized sample were evaluated by the photodegradation of rhodamine B (RhB) and phenol under visible-light irradiation (λ > 420 nm). The decolorization of high-concentrated RhB (10^− 4 M) and the variation of the chemical oxygen demand (COD), demonstrated that the BiVO₄ photocatalyst was efficient in aromatic organic compounds degradation. The reduction of total organic carbon (TOC) (about 22.0% after 4.5 h of irradiation) showed that the mineralization of RhB over the BiVO₄ photocatalyst is realized. Additionally, much enhanced photocatalytic performance for phenol degradation was also realized with the assistance of appropriate amount of H₂O₂.     

Nb/N Co-Doped Layered Perovskite Sr2TiO4: Preparation and Enhanced Photocatalytic Degradation Tetracycline under Visible Light

Sr₂TiO₄ is a promising photocatalyst for antibiotic degradation in wastewater. The photocatalytic performance of pristine Sr₂TiO₄ is limited to its wide bandgap, especially under visible light. Doping is an effective strategy to enhance photocatalytic performance. In this work, Nb/N co-doped layered perovskite Sr₂TiO₄ (Sr₂TiO₄:N,Nb) with varying percentages (0–5 at%) of Nb were synthesized by sol-gel and calcination. Nb/N co-doping slightly expanded the unit cell of Sr₂TiO₄. Their photocatalytic performance towards antibiotic (tetracycline) was studied under visible light (λ > 420 nm). When Nb/(Nb + Ti) was 2 at%, Sr₂TiO₄:N,Nb(2%) shows optimal photocatalytic performance with the 99% degradation after 60 min visible light irradiation, which is higher than pristine Sr₂TiO₄ (40%). The enhancement in photocatalytic performance is attributed to improving light absorption, and photo-generated charges separation derived from Nb/N co-doping. Sr₂TiO₄:N,Nb(2%) shows good stability after five cycles photocatalytic degradation reaction. The capture experiments confirm that superoxide radical is the leading active species during the photocatalytic degradation process. Therefore, the Nb/N co-doping in this work could be used as an efficient strategy for perovskite-type semiconductor to realize visible light driving for wastewater treatment.     

Asymmetric TiO2 hybrid photocatalytic ceramic membrane with porosity gradient: Effect of structure directing agent on the resulting membranes architecture and performances

Asymmetric TiO₂ hybrid photocatalytic ceramic membranes with porosity gradient have been fabricated via acid-catalyzed sol–gel method. Different structure directing agents (SDAs) i.e. Pluronic P-123, Triton X-100, Tween 20 and Tween 80 were incorporated in the preparation of TiO₂ sol to obtain a porous multilayered TiO₂ coated on the alumina ceramic support. Six different SDA-modified membrane specimens were fabricated. Four of which were coated with the TiO₂ sols prepared using only one type of SDA. The remaining two specimens were fabricated via multilayer coating of different TiO₂ sols prepared using different types of SDAs. Physico-chemical and morphological properties of different TiO₂ layers were thoroughly investigated. The membrane M1 which had the most porous TiO₂ sub-layers showed a high pure water permeability of 155 L m⁻² h⁻¹ bar⁻¹. The membrane showed a relatively high Rhodamine B (RhB) removal of 2997 mg m⁻² over 8 h treatment duration in the batch photoreactor, second only to the Pluronic-based TiO₂ membrane (specific RhB removal of 3050 mg m⁻²). All membrane specimens exhibited good performances while operated in the flow-through photocatalytic membrane reactor. Over 91% of RhB removal capability was retained after 4 treatment cycles. All membranes also showed self-cleaning property by retaining >90% of initial flux after 4 treatment cycles. The flexibility of optimizing membrane performances by fine-tuning the porosity gradient configuration of the photocatalytic layer has also been demonstrated.