Fabrication Of Molybdenum Disulfide Based Composites And Their Application In Electrochemical Sensors

The graphene-like layered molybdenum disulfide(MoS2)has some properties similar to those of graphene,such as high chemical stability,large specific surface area and etc.At the same time,MoS2 also has high catalytic activity.Thus,it has been widely applied in various fields.However,MoS2 is a semiconductor and shows poor conductivity,which impedes its application in electrochemical analysis.In order to overcome the shortcoming,we combine MoS2 with some conductive materials and extend its application in electrochemical sensor.The main contents are summarized as follows:1.Fabrication and application of electrochemical quercetin sensor based on Pd/MoS2-ionic liquid functionalized ordered mesoporous carbonA Pd/MoS2-ionic liquid functionalized ordered mesoporous carbon(Pd/MoS2-IL?OMC)composite was prepared by using IL as anchor and OMC as substrate.MoS2 nanosheets were in situ prepared on the IL-OMC surface by hydrothermal method and then Pd nanoparticles were deposited on the obtained MoS2-IL-OMC via chemical reduction method.As the nanocomposite combined the high conductivity of IL-OMC and the catalytic activity of Pd nanoparticles and MoS2,the resulting sensor exhibited good response towards quercetin(QR).Its linear detection range was 0.020-10?mol·L-1,with a detection limit of 8.0 nmol·L-1(S/N = 3)and a sensitivity of 150.1?mol·L-1(?mol·L-1)-1 cm-2.It also showed good reproducibility and stability,and could be applied to the detection of QR in dried blueberries and grape juice.2.MoS2/porous graphene composite based electrochemical sensor for luteolinA MoS2/porous graphene composite(MoS2/PGN)was synthesized by a simple hydrothermal method.The porous structure of pGN effectively prevented the aggregation of GN sheets and could provide large specific surface area for MoS2 growing.Therefore,the stacking of MoS2 nanosheets was effectively restrained and it showed few-layer structure,thus the catalytic property of MoS2 was enhanced remarkably.In addition,the porous structure of pGN could shorten the diffusion pathways and facilitate the electron transfer of target analyte.Hence,the composite modified electrode presented sensitive response to luteolin.The linear detection range was 0.010-5.0 ?mol·L-1 and the low detection limit was 6.0 nmol·L-1(S/N = 3)).The sensor was successfully applied in the detection of luteolin in real samples.3.Fabrication of surface-molecularly imprinted poly-carbazole on MoSz/graphene-carbon nanotubes nanocomposite modified electrode and the electrochemical determination of luteolinA MoS2/graphene-carbon nanotubes(MoS2/GN-CNTs)nanocomposite was prepared by hydrothermal method.The nanocomposite combined the high catalysis of MoS2 with the superior electronic conductivity of GN-CNTs,and exhibited highly sensitive electrochemical response towards luteolin.A electrodeposited surface-molecularly imprinted polymer(MIP)film,based on carbazole monomer and luteolin template,was used to improve the selectivity.Thus the resulting electrochemical sensor MIP/MoS2/GN-CNTS/GCE showed good performance.Its limit of detection and linear detection range were 9.0 nmol·L-1(S/N = 3)and 0.040-2.0 ?mol·L-1,respectively,while its sensitivity was 381.3 ?A(?mol·L-1)-1 cm-2.In addition,the sensor presented outstanding capability of resistant to interference and could distinguish luteolin from its analogues.It was applied to the determination of luteolin in carrot and chrysanthemum tea samples.