Bi0/Bi2O2CO3/N-TiO2复合材料的制备及其光催化性能

利用TiO2纳米带作为基底,乙二胺作为还原剂及氮源,采用溶剂热法合成光催化复合材料Bi0/Bi2O2CO3/N-TiO2.通过XRD、SEM、TEM等对催化剂的结构进行了表征.结果显示,直径为1.2～2.1 nm的单质铋(Bi0)和碳酸氧铋(Bi2O2CO3)的复合量子点均匀生长在一维TiO2纳米带(TiO2 NBs)表面.在可见光照射下,相比于TiO2 NBs(降解率30.95％),Bi0/Bi2O2CO3/N-TiO2在3 h内实现了对有机污染物罗丹明B的高效降解(降解率95.02％).活性物质捕获实验证实,h+和?OH是材料参与光催化降解罗丹明B的主要活性物质.     

N-TiO2/Ti3C2复合材料的原位合成及其光催化性能

以钛碳化铝、氢氟酸、氟硼酸钠为原料，以尿素为氮源，通过简单的溶剂热反应，在高导电性的Ti3C2 MXenes（二维过渡金属碳化物）纳米片上原位生长氮元素掺杂的TiO2纳米片，合成了二维N-TiO2/Ti3C2光催化复合材料。采用X射线衍射仪、扫描电子显微镜、透射电子显微镜、X射线光电子能谱仪、紫外-可见漫反射光谱仪、光致发光光谱仪等对催化剂样品进行了结构表征。结果表明，在可见光照射下，N-TiO2/Ti3C2复合材料对罗丹明B（RhB）表现出较好的光催化降解性能，其降解速率是纯TiO2的8.41倍，在150min内，罗丹明B降解率达到96.3%。这主要是由于氮元素的掺杂缩小了TiO2的带隙，将光响应范围扩展到可见光区域。同时，TiO2纳米片的原位生长使其与具有优异电导率的Ti3C2 MXenes纳米片形成了紧密的接触界面，促进了光生载流子的分离和迁移。自由基捕获实验和电子自旋共振测试结果显示，•O2-和•OH是N-TiO2/Ti3C2光催化体系降解罗丹明B的主要活性物种。此外，N-TiO2/Ti3C2复合材料具有良好的稳定性和可重复利用性。     

Fe3+掺杂Bi2MoO6光催化剂的合成及其活性研究

以钼酸铵、硝酸铋和硝酸铁为原料,采用水热/溶剂热法合成了铁掺杂的钼酸铋光催化剂,用X-射线粉末衍射、扫描电镜及紫外-可见吸收光谱等进行表征,并以罗丹明B为模型污染物,考察了纳米钼酸铋对罗丹明B溶液的光催化降解活性;以噻吩作为典型的含硫污染物,评价样品的光催化氧化脱硫活性。结果表明,Fe元素掺杂导致Bi2 MoO6的尺寸下降,比表面积增大;Fe掺杂,Bi2 MoO6吸收边发生红移;光催化活性与Fe元素的掺杂浓度有关,当掺杂量为0.5%时,活性最高;Fe掺杂Bi2MoO6对模拟汽油具有较好的脱硫活性,模拟可见光照射3 h,可使用模拟汽油的硫含量降低至70μg/g以下,脱硫率达到89%。     

Bi2O2CO3微/纳米片的合成及其光催化降解RhB性能研究

以尿素为表面活性剂,通过水热法成功合成了片状Bi2O2CO3光催化剂。采用X射线衍射仪（XRD）、场发射扫描电子显微镜（FESEM）、透射电子显微镜（TEM）、选区电子衍射（SAED）和紫外-可见漫反射光谱（DRS）等方法对所合成样品进表征。结果表明：所合成样品尺寸均小于2 μm,其中0.1 g尿素所合成样品的吸收边为394 nm,禁带宽度为3.14 eV。以罗丹明B（RhB）为模拟污染物,研究了所合成样品的光催化性能。结果发现0.1 g尿素所合成的样品在可见光下200 min可将RhB降解掉30%,紫外光下120 min RhB的降解率为80%,均高于商品TiO2对RhB的降解率,显示出优异的光催化活性。自由基抑制实验表明,超氧自由基（?O2-）和空穴（h ）是Bi2O2CO3在光催化降解过程中主要的活性物种。循环降解实验发现所合成样品具有较高的稳定性。     

g-C3N4/Bi/Bi2WO6光催化材料的协同改性研究

以五水合硝酸铋[Bi（NO₃）₃·5H₂O]为铋源、二水合钨酸钠（Na₂WO₄·2H₂O）为钨源通过水热法制备出多孔钨酸铋（Bi₂WO₆）,并以纳米板条堆叠形成椭球结构的类石墨相氮化碳（g-C₃N₄）为基底通过溶剂热法在原位还原金属铋（Bi）的同时制备出具有Z型异质结构的g-C₃N₄/Bi/Bi₂WO₆（CN/B/BWO）复合光催化材料。采用X射线衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）、氮气吸附-脱附等温线（BET）、紫外-可见吸收光谱（UV-Vis）和光致发光（PL）光谱等检测手段对制备的样品进行了表征。结果表明,金属铋可以作为类石墨相氮化碳和钨酸铋之间的电荷转移媒介,其产生的表面等离子体共振（SPR）效应可协同增强光生电子-空穴对的分离效率和载流子的迁移率,从而提升样品的光催化活性。采用350 W氙灯照射30 min,样品CN/B/BWO-0.7对盐酸四环素（TC-H）的降解率达到99.94%,并对其降解机理进行了探讨。     

Bi2S3/CNFs复合材料制备及其光催化性能

采用水热法制备硫化铋(Bi2S3)和活性纳米碳纤维掺杂硫化铋复合材料(Bi2S3/CNFs),以降解水溶液中甲硝唑(MTZ)抗生素.通过XRD、SEM、TEM、FTIR、XPS、UV-Vis和PL等对样品的晶型、形貌、结构、元素组成、表面官能团、光学性质进行了表征.结果表明,活性纳米碳纤维(CNFs)引入Bi2S3中,可降低光生电子-空穴对的复合速率,提高其光催化活性.在可见光照射下,考察了Bi2S3/CNFs复合材料光催化降解MTZ的活性,发现CNFs掺量为47％(以Bi2S3质量计,下同)、MTZ质量浓度为10 mg/L,复合材料用量为60 mg时,Bi2S3/CNFs复合材料光催化性能优异,在3 h内,MTZ的降解率为92％.Bi2S3/CNFs复合材料在3次循环后也表现出良好的稳定性和可回收性.活性基团捕获实验表明,羟基自由基(?OH)、光生空穴(h+)和超氧自由基(?O2–)参与了Bi2S3/CNFs对MTZ的降解,而?OH和h+是该体系的主要活性组分,并在此基础上初步探讨了光催化反应机理.     

Fe^3＋掺杂Bi_2MoO_6光催化剂的合成及其活性研究

以钼酸铵、硝酸铋和硝酸铁为原料,采用水热/溶剂热法合成了铁掺杂的钼酸铋光催化剂,用X-射线粉末衍射、扫描电镜及紫外-可见吸收光谱等进行表征,并以罗丹明B为模型污染物,考察了纳米钼酸铋对罗丹明B溶液的光催化降解活性;以噻吩作为典型的含硫污染物,评价样品的光催化氧化脱硫活性。结果表明,Fe元素掺杂导致Bi2 MoO6的尺寸下降,比表面积增大;Fe掺杂,Bi2 MoO6吸收边发生红移;光催化活性与Fe元素的掺杂浓度有关,当掺杂量为0.5%时,活性最高;Fe掺杂Bi2MoO6对模拟汽油具有较好的脱硫活性,模拟可见光照射3 h,可使用模拟汽油的硫含量降低至70μg/g以下,脱硫率达到89%。     

柠檬酸改性Bi2O3光催化材料性能的研究

以Bi（NO3）3溶液为原料,浓氨水为矿化剂,在柠檬酸掺杂量为1％-3％（质量分数）的条件下制备了纳米Bi2O3粉体。以样品对水中罗丹明B的光催化降解性能为评价指标,对样品的光催化性能进行了评价。研究结果表明：采用水热合成法制备的柠檬酸改性纳米Bi2O3粉体光催化降解水中罗丹明B的反应为表观零级反应。当柠檬酸的掺杂量为1．5％时,样品的光催化性能最优,继续增加掺杂量,样品光催化性能有所下降。紫外光条件下样品的光催化性能优于日光条件下。     

纳米钼酸铋/偕胺肟纤维光催化剂的制备及性能研究

以Bi(NO3)3和Na2Mo O4为原料,偕胺肟纤维作为配体,采用液相法合成钼酸铋/偕胺肟纤维(Bi2Mo O6/AOCF),通过X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、能谱(EDS)对样品进行了表征分析。结果显示,颗粒状的Bi2Mo O6均匀分布在纤维表面,并以配位键的形式与纤维结合。以罗丹明B(Rh B)为模拟污染物来考察Bi2Mo O6/AOCF的光催化活性,实验表明,Bi2Mo O6/AOCF有着很好的光催化活性,并且在酸性条件下的催化活性更好。催化剂对活性黄、亚甲基蓝和甲基橙也表现出较好的光催化活性,且重复使用5次后对Rh B的降解率仍可以达到91.4%。光催化反应过程符合一级反应动力学。     

Bi2MoO6/Ag3PO4复合光催化剂的制备及其光催化性能EI北大核心CSCD

以片状的Bi2MoO6为前驱物,通过原位化学沉淀法制备了Bi2MoO6/Ag3PO4复合光催化剂,考察了其光催化降解罗丹明B（Rh B）的活性。研究表明：Bi2MoO6和Ag3PO4复合可显著提高光催化活性,Bi2MoO6和Ag3PO4匹配的能级结构有利于光生电子和空穴的分离,延长光生载流子的寿命;当Bi2MoO6的质量分数为35%时,复合光催化剂具有最佳的光催化活性。     

(1-x)(Bi1/2Na1/2)0.900Ba0.088Sr0.012TiO3-x(Bi1/2K1/2)TiO3无铅压电陶瓷的电学和力学性能

利用常规烧结方法制备出了多种A位离子掺杂的钛酸铋纳[(Bi1/2Na1/2)TiO3,BNT]无铅压电陶瓷.对BNT基陶瓷的电学性能和力学性能进行了研究.在(1-x)(Bi1/2Na1/2)0.900Ba0.088Sr0.012TiO3-x(Bi1/2K1/2)TiO3(x=0-0.14)陶瓷体系中,当x=0.10时,可获得最大压电常数(168pC/N).在1 kHz,这种陶瓷的介电常数、介电损耗和平面机电耦合系数分别为1 221,0.0361和0.2281.Curie温度随x的增加先增加,当x=0.12时,达到最高值(300℃),随后,当x值进一步增加,Curie温度降低.该种无铅压电陶瓷的Vickers硬度和断裂韧性分别为5.0GPa和2.0MP·m1/2,均高于Pb(Zr,Ti)O3陶瓷.     

含铋掺杂TiO2及其铋系光催化剂的研究现状

光催化氧化法是近年来发展较快的新技术之一,而高效光催化荆是该技术的核心.TiO2掺杂改性或新型可见光催化剂的研发是当前光催化研究的焦点.本论文就国内外对TiO2掺杂Bi、新型铋系光催化剂的研究现状进行了综述,并展望了该类可见光催化剂的发展前景.     

Phase transformations in the relaxor Na1/2Bi1/2TiO3 studied by means of density functional theory calculations

The relaxor material Na_1/2Bi_1/2TiO₃ (NBT) is an important basis for the development of lead‐free piezoceramics, but still many features of this material are not well understood. Here, we study the kinetics of phase transformations by octahedral tilts and A‐cation displacements in NBT by means of density functional theory calculations, employing ab initio molecular dynamics and nudged elastic band calculations. Our results show that the energetic differences between the low temperature rhombohedral, intermediate orthorhombic and other metastable phases are close to the room temperature thermal energy. Therefore, it is likely that above room temperature, several octahedral tilt patterns are present simultaneously on the local scale, just because of thermal vibration of the oxygen ions. Octahedral tilt transformations and A‐cation displacements show similarly high energy barriers, however, since the vibrational frequency of oxygen is higher, tilt transformations occur more frequently. Further, tilt transformations in which the oxygen octahedra get deformed the least are more probable to occur. We also find that the chemical A‐cation order affects energy barriers, influences the coupling between rotational and displacive modes and determines the stability of certain octahedral tilt orders. We conclude that the so‐called polar nanoregions in this material result from local octahedral tilt transformations and subsequent A‐cation displacements, which are driven by thermal vibration and are mediated by the underlying chemical order.     

The synthesis of biotemplate-based Bi2WO6/TiO2 composite photocatalyst for degradation of microcystin

Microcystin is a harmful hepatic toxin produced by cyanobacteria, is a serious threat due to its toxicity to water ecosystems, and it is found recently that TiO₂ photocatalyst is effective in degradation of microcystin. In this study, hierarchical porous Bi₂WO₆/ TiO₂ composite photocatalysts were synthesized with a novel hydrothermal method by using rice husk as the biological template. The results showed that the original micro- and nanopores of rice husk were efficiently replicated by the synthesized porous TiO₂ photocatalyst with a specific surface area of 137.09 m²/g, which increased by nearly 100 m²/g over the surface area. SEM, TEM, XRD, and XPS spectra showed that heterogeneous structures were formed by Bi₂WO₆ and TiO₂, with which process the crystal structures of both were not affected. In the meantime, we studied the effect of hierarchical porous TiO₂ photo-catalyst, pure TiO₂ photo-catalyst, Bi₂WO₆ photo-catalyst, Bi₂WO₆/ hierarchical porous TiO₂ photo-catalyst on degradation of 1 mg/L MC-LR, and the results showed that to use the unique silicon-carbon structure of rice husk to prepare hierarchical porous TiO₂ photo-catalyst can have the degradation rate of 53.5%, which is higher than that of commercially available TiO₂ photo-catalyst by 13.8%. Compared with a single photo-catalyst, the photo-catalytic activity of Bi₂WO₆/ hierarchical porous TiO₂ photo-catalyst is significantly improved. The optimal mingling amount of Bi₂WO₆ is 0.2 mol/mol. At this time, the degradation rate of MC-LR is 85.3%, and the main active substances for degradation are h+ and ·OH. In addition, the degradation process of MC-LR fit well with the kinetic model of Quasi Primary Reaction. The insight of green synthesis of Bi₂WO₆/ TiO₂ composite photocatalysts for degradation of microcystins was provided by this study.     

Bi2SiO5/SiO2的合成及催化丙烯气相环氧化反应

水热法合成了具有介孔特征的系列Bi2SiO5/SiO2催化剂（记为SBn,n为Si与Bi物质的量比,n=0.5、5、10、20、50）,并通过X射线粉末衍射、N2物理吸附-脱附和扫描电镜等技术对SBn催化剂进行表征。结果表明,以O2为氧源,SBn催化剂在气相丙烯环氧化反应中具有良好的催化活性。在温度330 ℃,SB20催化剂上环氧丙烷选择性达50%,对应丙烯转化率为0.6%;而在温度470 ℃时,SB20催化剂上丙烯转化率接近20%,但环氧丙烷选择性降至20%。     

Controlled synthesis of Bi2O3/BiOBr/Zn2GeO4 heterojunction photocatalysts with enhanced photocatalytic activity

BiOBr/Zn₂GeO₄ heterojunctions decorated by Bi₂O₃ quantum dots (QDs; named as Bi₂O₃/BiOBr/Zn₂GeO₄ hereafter) with intriguing micro/nanostructures have been constructed via a two‐step hydrothermal route. The compositions, phases, and morphologies of Bi₂O₃/BiOBr/Zn₂GeO₄ were investigated in detail. The light absorption ability, photocurrent responses, and photocatalytic degradation of methylene blue (MB) experiments were performed to evaluate the photocatalytic activity of the micro/nanoheterostructured Bi₂O₃/BiOBr/Zn₂GeO₄, which present a degradation efficiency of 88% after 240 minutes under light irradiation (λ = 300‐600 nm) over 100 mg Bi₂O₃/BiOBr/Zn₂GeO₄ in a 100 mL, 4 mg/L MB solution. The photocatalytic performance could be retained for at least four runs, indicating its excellent reusability for the degradation of MB in aqueous solution. It is found that the photodegradation of MB over Bi₂O₃/BiOBr/Zn₂GeO₄ is mainly ascribed to a hole oxidation mechanism in combination with a superoxide oxidation process. The high photocatalytic performance of Bi₂O₃/BiOBr/Zn₂GeO₄ upon UV light irradiation can be attributed to the effective charge separation and smoothly transferring of the photogenerated charge carriers throughout the heterojunction. The feasible strategy of preparing Bi₂O₃/BiOBr/Zn₂GeO₄ ternary composites is also of benefit to fabricate other efficient heterojunction catalysts with specific morphologies and properties.     

钨与铋摩尔比对Bi2WO6微晶形貌及光学性能的影响

以Bi（NO3）3·5H2O和Na2WO4·2H2O为原料,采用水热法合成了Bi2WO6微晶。采用x射线衍射、场发射扫描电子显微镜、透射电子显微镜和紫外一可见漫反射光谱研究n（W）／n（Bi）摩尔比对合成Bi2WO6粉体的形貌和光学性能的影响。结果表明：不同的n（W）／n（Bi）比对水热法合成Bi2WO6微晶有很大影响;在n（W）/n（Bi）=0．5：1．0～2：2范围内均可制备出斜方晶系钨铋矿型结构的Bi2WO6微晶。当n（W）／n（Bi）=1：2时,Bi2WO6的结晶性能最好;随n（W）／n（Bi）比增加,Bi2WO6的形貌由卡片状球形结构向致密球形结构转变。光学性质研究表明,所制备的微晶表现出较强的紫外吸收特性,随n（W）／n（Bi）比增加,其带隙呈现减小的趋势,当n（W）／n（Bi）=1.5：2.0时所得样品的带隙最小,为2．58eV。     

Spark Plasma Sintering-Assisted Synthesis of Bi2Fe4O9/Bi25FeO40 Heterostructures with Enhanced Photocatalytic Activity for Removal of Antibiotics

Bismuth ferrite-based heterojunction composites have been considered as promising visible-light responsive photocatalysts because of their narrow band gap structure; however, the synthetic methods reported in the literature were usually time-consuming. In this study, we report a facile and quick preparation of bismuth ferrite-based composites by the hydrothermal method, combined with spark plasma sintering (SPS), a technique that is usually used for the high-speed consolidation of powders. The result demonstrated that the SPS-assisted synthesized samples possess significant enhanced photoelectric and photocatalytic performance. Specifically, the SPS650 (sintered at the 650 °C for 5 min by SPS) exhibits a 1.5 times enhancement in the photocurrent density and a 3.8 times enhancement in the tetracycline hydrochloride photodegradation activity than the unmodified bismuth ferrite samples. The possible influence factors of SPS on photoelectric and photocatalytic performance of bismuth ferrite-based composites were discussed carefully. This study provides a feasible method for the facile and quick synthesis of a highly active bismuth ferrite-based visible-light-driven photocatalyst for practical applications.     

Preparation of Bi2O3@PCPA-KH590/chloroprene composites with good mechanical properties under high-filling

As a “green” radiation protection material with the potential to replace lead oxide, bismuth oxide has more research applications in the field of γ protection. However, due to their different surface properties, there are compatibility and interaction problems between metal oxides and rubber. To enhance the performance of bismuth oxide in neoprene, Bi₂O₃@PCPA-KH590 was prepared by coating bismuth oxide with polyphenol/polyamine and grafting KH590 on the surface of bismuth oxide. This allows for creating more active sites with the help of polyphenol/polyamine, enabling KH590 to be grafted onto bismuth oxide particles. The S functional group on the silane coupling agent is then cross-linked with the rubber substrate, enhancing the dispersibility of the bismuth oxide powder. This improvement not only improves the dispersibility of the bismuth oxide powder but also enhances the mechanical properties of the rubber composite material. Compared with pure CR, the mechanical properties of 60 wt% filler-modified powder composites can still be maintained at a high level, with the tensile strength reaching 12.83 Mpa. In sum, the proposed method appears feasible for preparing highly filled radiation protection rubber-based materials.     

CuO/Bi2O3催化合成3-己炔-2,5-二醇

采用均匀沉淀法在水热体系中制备出CuO/Bi2O3粉体催化剂,讨论了水解过程中pH对生成晶形沉淀的影响,通过TG分析确定合适的焙烧温度。采用XRD、SEM、BET等技术对催化剂进行了表征,结果表明,在400℃下焙烧可得到晶形完善,比表面积较大,平均尺寸0.1～0.5μm的粉体颗粒。在高压反应釜中考察了Bi质量分数、反应温度、乙炔分压、pH对催化活性的影响,得到了催化合成3-己炔-2,5-二醇的适宜反应条件:Bi质量分数12%,反应温度120℃,乙炔分压1.0 MPa,pH=6～7,产物收率达20.10%。