（急）In2O3-CuO的制备及其光活化下的室温甲醛气敏性能

以InCl3.4H2O和Cu(NO3)2.3H2O为原料,尿素为沉淀剂,采用水热法制备In2O3-CuO复合材料。通过微观结构表征和宏观气敏特性相关联,探究紫外光活化In2O3-CuO复合材料的气敏性能与传感机制。研究结果表明,In2O3-CuO复合材料在375 nm 紫外光照射室温（25℃）条件下对50 ppm甲醛气体的灵敏度为298,与纯In2O3（2.4）相比灵敏度提高124倍,气敏性能的巨大提升归因于In2O3与CuO形成的p-n异质结,协同光活化条件下异质结界面产生的光生电子-空穴与氧物种（O2和O2-）间建立了氧的光活化吸附－解吸循环,使得室温下材料的气体吸附－解吸过程和表面反应增强。为光敏材料的应用和室温气体传感材料的设计提供了新的策略。     

棒状FeS2/NiS2和FeP/Ni2P材料的合成与催化性能比较

以Fe(NO3)3?9H2O、Ni(NO3)2?6H2O、硫粉或NaH2PO2?H2O为原料,通过两步法合成了FeS2/NiS2、FeP/Ni2P复合材料,通过XRD、SEM和TEM对材料的结构和形貌进行了表征,研究了其析氧催化性能。结果表明,上述催化剂均具有很好的催化性能。在电流密度为10 mA/cm2时,FeP/Ni2P需要较小的过电位（300 mV）,表现出比FeS2/NiS2（300 mV）更好的催化活性。FeP/Ni2P催化剂相应的塔菲尔斜率值（48 mV/dec）也比FeS2/NiS2 (71 mV/dec)的小,表示在析氧反应中FeP/Ni2P催化剂具有更好的催化动力学性能。     

纳米多孔Fe_2O_3–Fe_3O_4/Ni复合材料作为锂离子电池负极材料的电化学性能

通过在NH4F+H2O的乙二醇溶液中阳极氧化铁箔,制备了纳米多孔结构的铁氧化物(Fe2O3–Fe3O4),然后在纳米多孔中电沉积镍,再经过400°C退火0.5 h,获得了镍与纳米多孔氧化铁的复合材料(Fe2O3–Fe3O4/Ni)。考察了电流密度和时间对镍沉积的影响。用扫描电镜、能谱仪、X射线衍射仪表征了复合材料的表面形貌、元素组成和物相,测试了其电化学性能并与未经电沉积镍的纳米多孔氧化铁(Fe2O3–Fe3O4)比较。结果表明,氧化铁由Fe2O3和Fe3O4组成。镀镍的最佳电流密度为2.0 m A/dm2,时间30 s。该纳米多孔Fe2O3–Fe3O4/Ni复合材料作为锂离子电池负极材料表现出更好的电化学性能──经过50次充放电循环后的放电比容量仍有438.3 m A·h/g,而Fe2O3–Fe3O4电极的放电比容量仅为110.6 m A·h/g。Fe2O3–Fe3O4/Ni电极的循环稳定性和倍率性能优异。     

g-C3N4/BiOBr异质结对罗丹明B可见光催化活性研究

采用硝酸剥离的二维g-C_3N_4纳米片为基材,通过分散掺杂溴化钾(KBr)和五水合硝酸铋(Bi(NO_3)_3·5H_2O),构建了花状的g-C_3N_4/BiOBr异质结,采用x射线衍射、场发射扫描电子显微镜和傅里叶变换红外光谱等研究了制备的复合光催化剂的微观结构和形态特征。该异质结对罗丹明B为代表的一系列偶氮类化合物产生光催化降解性能。良好的结果可归结于异质结的形成可以充分捕获催化剂表面的光激化电子,同时提高了光生载流电子的转移和分离效率,催化性能,稳定性以及降解率等。     

自掺杂NiO/SrTiO_(3-x)异质结的合成及可见光催化性能研究

通过两步法合成了一种新颖的NiO/SrTiO_(3-x)异质结光催化剂,首先,通过高温固相法合成不同Ti~(3+)自掺杂的SrTiO_(3-x),再利用浸渍法合成NiO/SrTiO_(3-x)异质结。X射线衍射(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)和紫外可见漫反射(UV-vis-DRS)等仪器被系统的用来表征SrTiO_(3-x)和NiO/SrTiO_(3-x)异质结,并对它们的物理化学性质进行分析。在可见光条件下用罗丹明B来考察样品的光催化活性,研究表明NiO/SrTiO_(3-x)具有优异的光催化性能,远远优于Ti~(3+)自掺杂的SrTiO_(3-x)。而且,NiO/SrTiO_(3-x)异质结的循环实验结果表明该材料不仅具有高效的光催化剂性能,而且还拥有良好的稳定性。     

新型磁性异质结材料的制备及其光降解染料废水的性能

为了解决光催化剂在光生电子与空穴中分离效率低且难以回收利用的问题，以钛碳化铝(Ti₃AlC₂)为原料，通过Li F+HCl刻蚀法、共沉淀法、溶剂热法和异种电荷静电自组装，获得具有磁分离性能的新型异质结光催化材料AMHNTs/TiO₂-Ti₃C₂T_x(H&M)，对其进行结构表征，并选取偶氮类染料甲基橙(MO)为污染物模型，考察模拟太阳光下H&M的降污性能及降解机理。结果表明：制备的异质结H&M融合了二维层状与一维管状的结构特征，提高电子的传导输送，具有良好的光催化活性和磁回收性，且对MO有较好的降解性能，为构筑新型磁性无机异质结光催化材料和染料的光降解提供有价值的参考。     

层状双氢氧化物掺杂Cu2O/PAN光催化纤维的制备及性能

层状双氢氧化物(LDHs)作为柔性化学材料,具有可调节的电子性能和独特的二维结构.构建了Ni3Fe1-LDH@Cu2O异质结构光催化剂,并将其负载于聚丙烯腈(PAN)纳米纤维膜上.通过在可见光下对亚甲基蓝(MB)的降解来评价不同Ni3Fe1-LDH@Cu2O添加量的光催化纤维的性能.在暗室吸附30min、可见光照射60...     

CH_4/CO_2重整反应中NiO-Ce_xZr_(1-x)O_2/Al_2O_3催化剂的研究

通过共沉淀法制备了一系列CexZr1-xO2的介孔材料,采取浸渍法负载10 wt%Ni O/γ-Al2O3,得到不同组成的Ni O-CexZr1-xO2/Al2O3(x=0,0.25,0.5,0.75,1)催化剂。对所得催化剂进行BET、XRD表征分析,同时考察了在相同条件下CH4/CO2重整反应中的催化性能。结果表明:Ni O-Ce0.75Zr0.25O2/Al2O3催化剂有较好的稳定性和抗积炭性,CH4、CO2转化率和H2收率分别可达85.5%、86.4%和93.8%;碱金属助剂有大的比表面积,可使活性组分Ni O充分分散,且随着Ce O2含量增加分散度也提高,使得催化剂抗积炭性能增强,催化活性提高。     

SnO_2/In_2O_3纳米材料的制备及其吸附-光催化性能研究

采用水热法制备了一系列不同SnO2/In2O3比例的光催化剂,应用X射线粉末衍射(XRD)和扫描电子显微镜(FESEM)对其微观形貌和晶型进行了分析,通过紫外-可见分光光度计(UV-Vis)评价了复合材料对甲基橙(MO)溶液的吸附性能及催化活性,考察了Sn/In比例值对SnO2/In2O3样品吸附性能及光催化性能的影响。结果表明:当Sn与In摩尔比为2∶1时,对MO的吸附性能和催化性能最好。     

温度对n-ZnO/p-diamond薄膜异质结器件制备和电学性质的影响

采用反应磁控溅射法在p型硼掺杂金刚石(BDD)薄膜衬底上制备了非有意掺杂n型氧化锌(ZnO)薄膜。利用XRD、SEM、I-V特性曲线对n-ZnO/p-BDD薄膜复合结构进行表征分析。n-ZnO多晶膜沉积在p-BDD膜上形成了具有良好整流特性的异质结。在空气中对异质结进行退火处理,研究了退火(400℃,700℃)对异质结性质的影响。实验表明,较高退火温度处理,可获得多取向的ZnO膜,晶粒尺寸增大,n-ZnO/p-BDD异质结开启电压减小。不同温度下的电学性质测量结果证明该异质结适合在高温环境下工作。     

Au nanoparticle modified single-crystalline p-type LaRhO3/SrTiO3 heterostructure for high performing VOCs sensor

Since the discovery of two-dimensional electron gas (2DEG) confined at perovskite LaAlO₃/SrTiO₃ (LAO/STO) interface, extensive efforts have been devoted to explore novel high-performance all oxide electronic devices, including gas sensors. Among perovskite oxides, LaRhO₃ (LRO) possesses unique p-type conductivity and catalytic properties, which offer promising benefits for sensing volatile organic compounds (VOCs) molecules. In this work, single-crystalline p-type LRO thin film was epitaxially grown on STO (110) substrate as a high-quality sensing channel. Drastic improvement of sensing performance of LRO probed by 50 ppm ethanol was accomplished by appropriate Au decoration layer, e.g., an increased response (from 2.5 to 8.4), reduced optimal operation temperature (from 325 to 275 °C), decrease of response/recovery time (from 100/85 to 54/23 s) and improvement of detection limit (from 5000 to 250 ppb). X-ray photoelectron spectroscopy (XPS) indicates that Au nanoparticles facilitates the formation of reactive chemisorbed oxygen species, which substantially trigger the charge exchange occurring at ethanol/LRO interface. Our work highlights the importance of surface engineering toward high-performance perovskite based VOCs sensors.     

Room temperature ammonia sensing based on graphene oxide integrated flexible polyvinylidenefluoride/cerium oxide nanocomposite films

ABSTRACT

In this work, novel room temperature (RT) ammonia (NH₃) sensors comprising graphene oxide (GO) integrated polyvinylidenefluoride (PVDF)/cerium oxide (CeO₂) nanocomposite films have been prepared via simple solution casting technique. The structural and morphological characteristics of flexible tertiary PVDF/CeO₂/GO nanocomposite films have been investigated using various analytical techniques and their NH₃ gas-sensing performance was evaluated at RT and the relevant sensing mechanism was established. The flexible PVDF/CeO₂/GO nanocomposite films responded strongly to NH₃ gas with enhanced gas sensing properties at RT as compared with various other volatile organic compounds (VOCs) such as acetone, ethanol, formaldehyde and toluene.     

掺杂Fe~(3+)纳米TiO_2膜光催化降解VOCs

利用玻璃弹簧负载TiO_2膜光催化降解VOCs,以室内空气污染物甲醛、丙酮和甲苯为目标污染物,采用自制反应器,分析了初始浓度、空气湿度和气体流量对甲苯降解效果的影响,考察了三种物质混合的降解效果,对比了在相同条件下单一甲苯和VOCs中甲苯的降解效果。结果表明,气体流速5 L·min~(-1)时,甲苯的降解效率为74.6%,空气湿度为30%时,甲苯降解率为81.6%,初始浓度为0.173 mg·L~(-1)时,甲苯降解率为94%,在这三种情况下,甲苯降解效果较好;对VOCs中甲苯和单一甲苯的降解效果进行对比,发现混合气体中甲苯的降解率在反应205 min后高于单一甲苯。     

Room temperature formaldehyde sensors with enhanced performance, fast response and recovery based on zinc oxide quantum dots/graphene nanocomposites

Novel zinc oxide quantum dots (ZnO QDs) decorated graphene nanocomposites were fabricated by a facile solution-processed method. ZnO QDs with a size ca. 5 nm are nucleated and grown on the surface of the graphene template, and its distribution density can be easily controlled by the reaction time and precursor concentration. The ZnO QDs/graphene nanocomposite materials enhance formaldehyde sensing properties by 4 times compared to pure graphene at room temperature. Moreover, the sensors based on the nanocomposites have fast response (ca. 30 seconds) and recovery (ca. 40 seconds) behavior, excellent room temperature selectivity and stability. The gas sensing enhancement is attributed to the synergistic effect of graphene and ZnO QDs. The electron transfer between the ZnO QDs and the graphene is due to oxidation process of the analyzed gas on the ZnO QDs' surface. This proposed gas sensing mechanism is experimentally proved by DRIFT spectra results. The ZnO QDs/graphene nanocomposites sensors have potential applications for monitoring air pollution, especially for harmful and toxic VOCs (volatile organic compounds).     

Enhanced hydrogen gas sensing properties of Pd-doped SnO2 nanofibres by Ar plasma treatment

Pd-doped SnO₂ nanofibres were prepared by electrospinning and magnetron sputtering. It was found that the efficiency of gas sensing properties in these fibres depends primarily on the density of oxygen vacancies, which can be regulated by plasma treatment. We demonstrated that moderate plasma treatment can increase the oxygen vacancy as well as improve the gas sensing performance of SnO_2. However, excessive plasma treatment led to the production of other substances that deteriorated the gas sensing performance. Furthermore, the best results for hydrogen gas sensing were obtained when the nanofibres were subjected to plasma treatment for 1 min. The fabricated material demonstrated a response of more than 53 for 500 ppm hydrogen at the optimum temperature (130 °C), which is a significant improvement as compared to sensors without plasma treatment. Evidently, plasma treatment is an effective method to further enhance the sensing properties of the fabricated nanofibres.     

Oxygen vacancy engineering on copper-manganese spinel surface for enhancing toluene catalytic combustion: A comparative study of acid treatment and alkali treatment

Copper-manganese spinel is a low-cost VOCs catalytic combustion catalyst with good performance. Oxygen vacancy has excellent properties for oxygen activation and VOCs dehydrogenation activation, which is beneficial for the catalytic combustion of VOCs. In this study, a large number of oxygen vacancies were introduced on the copper-manganese spinel surface by selective dissolution method (acid treatment and alkali treatment) for catalytic combustion of toluene. Furthermore, the effects of acid treatment and alkali treatment on the catalytic performance, oxygen vacancy amount, physical and chemical properties, and toluene catalytic combustion mechanism of copper-manganese spinel were studied. Both acid treatment and alkali treatment can produce large quantities of oxygen vacancies on the copper-manganese spinel surface. The generation of surface oxygen vacancies can greatly improve the catalytic combustion activity of copper-manganese spinel. At 240 °C, the combustion rate of toluene increased by 8.8 times for the acid-treated catalyst and 11.2 times for the alkali-treated catalyst. The numerous surface oxygen vacancies, Mn³⁺/Mn⁴⁺ at the ratio of 1.11 and appropriate acidity result in the alkali-treated catalyst exhibiting excellent catalytic activity and stability for toluene combustion. This strategy provides a new method to further improve catalytic combustion activity of copper-manganese spinel and a reference for the development of the surface oxygen vacancy engineering of transition metal oxides.     

Recent progress of Ga2O3-based gas sensors

In recent years, gas sensors fabricated from gallium oxide (Ga₂O₃) materials have aroused intense research interest due to the superior material properties of large dielectric constant, good thermal and chemical stability, excellent electrical properties, and good gas sensing. Over the past decades, Ga₂O₃-based gas sensors experienced rapid development. The long-term stable Ga₂O₃-based gas sensors for detecting oxygen and carbon monoxide have been commercialized and renowned with extremely good gas sensing characteristics. Recent pioneering studies also exhibit that the Ga₂O₃-based gas sensors possess great potentials in applications of detecting nitrogen oxides, hydrogen, volatile organic compounds and ammonia gases. This article presents recent advances in gas sensing mechanism, device performance parameters, influence factors, and applications of Ga₂O₃-based gas sensors. The impacts of influence factors, doping, material structure and device structure on the performance of gas sensors are discussed in detail. Finally, a brief overview of challenges and opportunities for the Ga₂O₃-based gas sensors is presented.     

沸石及其复合物气体传感器的研究与应用

半导体金属氧化物是一种常见的气敏材料,以该类型材料作为敏感材料可以设计出具有不同传感原理的气体传感器,但选择性和灵敏度不佳却一直是该类气体传感器的不足。为了解决该问题,常将气敏材料与沸石进行复合,制备金属氧化物/沸石气体传感器,利用沸石独特的物理、化学特性来改善金属氧化物的气敏特性。近年来,许多研究者对金属氧化物/沸石气体传感器进行了研究,使该类传感器对目标气体的选择性与灵敏度均有了提升。为了更好地总结已有的研究内容,以气体传感器的检测原理为主线,对金属氧化物/沸石气体传感器进行了总结,结合沸石对气敏特性的改善进行归纳梳理,从传感器的制备方法、气敏特性和敏感机理等多方面进行了详细的整理和分析,为后续此类工作的开展提供基础。     

聚丁二炔气敏传感应用的研究现状及展望

分析了聚丁二炔作为气敏传感材料的机理,总结了不同结构聚丁二炔衍生物作为气敏传感材料的研究现状。本文以聚氨酯、石墨烯、二硫化钼、纤维素纳米晶等增强材料为例,阐述了聚丁二炔复合材料的气敏增强原理、优点及存在的问题,介绍了如食物腐败的检测、便携腕式传感器等新型传感场合的应用研究。目前,聚丁二炔作为气敏传感材料还处于起步阶段,光学转变机理不明确、侧基改性工艺烦琐、官能团种类有限、易受环境影响失效等问题都亟待解决;未来应拓宽对增强材料的选择,调控复合材料的结构以实现对待测气体的高选择性和高灵敏度响应,更要发挥聚丁二炔复合材料成型工艺简单、与环境相容性好的优点,制备更具功能化的气敏材料。     

Adsorption/desorption of toluene on a hypercrosslinked polymeric resin in a highly humid gas stream

In many sources of volatile organic compounds(VOCs), large amounts of water vapor come from the air and the reactors. The relative humidity(RH) of exhaust gas is normally N60% and is supersaturated. Maintaining the property of adsorbent on VOCs in a highly humid gas stream is a serious industrial problem. In this study, the adsorption/desorption behavior of toluene in a micro-mesoporous polymeric resin was investigated in a highly humid environment to explore the influence of abound water vapor on resin adsorption and regeneration.This resin could selectively adsorb toluene at an RH of 80%, and its adsorption property was unaffected by the presence of water vapor. In the case of humidity saturation, the resin displayed a high adsorption capacity at a moisture content of b30%. Therefore, the polymer resin is an excellent water-resistant adsorbent of VOCs.In the regenerative experiment, the resin maintained its original adsorption capability after four adsorption/desorption cycles of toluene purging with nitrogen gas at 120 °C. The resin exhibited excellent regeneration performance at high humidity.