基于二氧化钛/石墨烯纳米复合物的光电化学适体传感器测定土霉素

采用水热法在掺杂氟的SnO2(FTO)导电玻璃上生长纳米二氧化钛(TiO2),并通过简单的电化学还原在其表面原位沉积石墨烯,以纳米TiO2/石墨烯为光电传感基底,构建用于土霉素(OTC)检测的光电化学适体传感器。通过扫描电镜表征了复合材料的形貌,电化学工作站测试了单一材料与复合材料的光电响应性能。结果表明,相比于单一的TiO2,TiO2/石墨烯复合材料能明显增强光电流响应,提高灵敏度。基于土霉素适配体对土霉素的高特异性识别,将其固定在TiO2/石墨烯复合纳米材料修饰的FTO表面,可用于土霉素的测定。该方法对目标物的线性范围为5.0×1.0^-9~5.0×10^-6mol/L,相关系数(r)为0.9887,检出限为1.0×1.0^-9mol/L。方法简单、成本低、线性范围宽,有望于实际样品中土霉素残留的测定。

一种基于激光直写技术的自供电光电化学传感器

设计了一种基于激光直写技术制备的二氧化钛/石墨烯(TiO_(2)/Graphene)为光阳极和铂电极为阴极的葡萄糖自供电光电化学传感器。探究了钛源添加量、纳米激光作用仪输出功率与溶液pH对传感器性能的影响。实验结果表明,所设计的传感器对葡萄糖浓度在50~500μmol·L^(-1)之间呈现出良好的线性关系,检出限为6.8μmol·L^(-1),最大输出功率为2.01μW·cm^(-2)。

Synthesis of graphene/tourmaline/TiO_2 composites with enhanced activity for photocatalytic degradation of 2-propanol

We report the construction of a graphene/tourmaline/TiO2(G/T/TiO2)composite system with enhanced charge‐carrier separation,and therefore enhanced photocatalytic properties,based on tailoring the surface‐charged state of graphene and/or by introducing an external electric field arising from tourmaline.A simple two‐step hydrothermal method was used to synthesize G/T/TiO2composites and poly(diallyldimethylammonium chloride)‐G/T/TiO2composites.In the photocatalytic degradation of2‐propanol(IPA),the catalytic activity of the composite containing negatively charged graphene was higher than of the composite containing positively charged graphene.The highest acetone evolution rate(223?mol/h)was achieved using the ternary composite with the optimum composition,i.e.,G0.5/T5/TiO2(0.5wt%graphene and5wt%tourmaline).The involvement of tourmaline and graphene in the composite is believed to facilitate the separation and transportation of electrons and holes photogenerated in TiO2.This synergetic effect could account for the enhanced photocatalytic activity of the G/T/TiO2composite.A mechanistic study indicated that O2??radicals and holes were the main reactive oxygen species in photocatalytic degradation of IPA.

Direct fabrication of highly porous graphene/TiO_2 composite nanofibers by electrospinning for photocatalytic application

We reported the fabrication of highly porous graphene/TiO2 composite nanofibers in the form of a nonwoven mat by electrospinning followed by calcination in air at 450°C.The graphene can uniformly disperse in highly porous TiO2 nanofibers.The highly porous graphene/TiO2 composite nanofibers exhibited excellent catalytic activities.The new method for producing graphene/TiO2 composite nanofibers is versatile and can be extended to fabricate various types of metal oxide and graphene nanocomposites.

Catalytic performance and synthesis of a Pt/graphene-TiO_2 catalyst using an environmentally friendly microwave-assisted solvothermal method

A Pt/graphene‐TiO2catalyst was prepared by a microwave‐assisted solvothermal method and was characterized by X‐ray diffraction,scanning electron microscopy,transmission electron microscopy,cyclic voltammetry,and linear sweep voltammetry.The cubic TiO2particles were approximately60nm in size and were distributed on the graphene sheets.The Pt nanoparticles were uniformly distributed between the TiO2particles and the graphene sheet.The catalyst exhibited a significant improvement in activity and stability towards the oxygen reduction reaction compared with Pt/C,which resulted from the high electronic conductivity of graphene and strong metal‐support interactions.

Direct electrospinning method for the construction of Z-scheme TiO_2/g-C_3N_4/RGO ternary heterojunction photocatalysts with remarkably ameliorated photocatalytic performance

A series of Z-scheme TiO2/g-C3N4/RGO ternary heterojunction photocatalysts are successfully constructed via a direct electrospinning technique coupled with an annealing process for the first time. They are investigated comprehensively in terms of crystal structure, morphology, composition, specific surface area, photoelectrochemical properties, photodegradation performance, etc. Compared with binary TiO2/g-C3N4 and single-component photocatalysts, ternary heterojunction photocatalysts show the best photodegradation performance for RhB under stimulated sunlight. This can be attributed to the enlarged specific surface area (111.41 m2/g), the formation of Z-scheme heterojunction, and the high separation migration efficiency of photoexcited charge carriers. A potential Z-scheme mechanism for ternary heterojunction photocatalysts is proposed to elucidate the remarkably ameliorated photocatalytic performance based on active species trapping experiments, PL detection test of hydroxyl radicals, and photoelectrochemical properties.