Synthesis Of Cobalt And Molybdenum Nanocomposites And The Drug Loading Behaviors And Electrocatalysis Study

Oral administration is the most common method of medication.However,it must overcome some shortcomings such as low solubility in water、poor stability and acidic gastric environment.In order to improve oral bioavailability of insoluble drugs,reduce the toxic and side effects of the drug itself and exert the efficacy,there is an urgent need for a new type of drug carrier to solve this problem.Novel nanostructured inorganic materials combine the advantages of abundant channels pores,high specific surface area and good biocompatibility,the solubility and bioavailability of insoluble drugs can be effectively improved once they are confined in nanochannel structures and increase the contact area between drugs and dissolution medium.In addition,the materials with this type of structure are also used as electrocatalysts,they can catalyze the hydrogen evolution reaction（HER）,oxygen evolution reaction（OER）and overall water splitting efficiently to prepare clean energy of hydrogen and solve environmental problems.In this study,hollow Co₉S₈nanospheres were used as templates to synthesize Co₉S₈@MoS₂ inorganic nanocomposites that MoS₂ nanosheets in-situ growth on the surface of templates by two-step heating hydrothermal method.And then Co₉S₈@MoS₂ used as drug carrier and electrocatalyst and their various indicators were assessed.The main research contents are as follows:1.The Co₉S₈@MoS₂inorganic nanocomposite with abundant pore channels and high specific surface was obtained by two-step heating hydrothermal method,which MoS₂ nanosheets were in-suite self-assembly on the surface of hollow Co₉S₈ nanospheres,sodium molybdate aqueous solution as molybdenum source and the thiourea as vulcanizing agent,respectively.They were calcined at different temperature to prepared a series of complexes Co₉S₈@MoS₂-T（T represents temperature）.The morphology,element and crystal form were characterized by scanning electron microscopy（SEM）,X-ray powder diffraction（XRD）and X-ray photoelectron spectroscopy（XPS）.By adjusting the calcining temperature to 400℃,the prepared Co₉S₈@MoS₂-4with clear topography and the most abundant active sites,which had great potential in drug carriers and electrocatalysts.2.The insoluble ibuprofen（Ibu）was loaded on Co₉S₈@MoS₂-T by solvent evaporation and formed a series of Ibu-Co₉S₈@MoS₂-T carrier composites.The Ibu-Co₉S₈@MoS₂-T were confirmed by TEM,XRD,IR and SEM and the Ibu had been exactly loaded in the composites by analysing the characterization spectrum.Compared with their drug loading,the experimental results showed that Ibu-Co₉S₈@MoS₂-4 can reach the highest loading amount at 36.88%.Then,the dissolution of Ibu-Co₉S₈@MoS₂-4 was tested in different medium（pH=6.8phosphate buffer solution,water and pH=7.4 phosphate buffer solution）and the corresponding curve was drawn.It showed that the cumulative drug release amount was 76.6%at pH=7.4,which was higher than 68.2%in water and 72.8%at pH=6.8 solution and also higher than the solubility of pure Ibu in water.The test demonstrated that the materials can significantly improve solubility and had pH dependence when the Ibu was loaded on Co₉S₈@MoS₂-4 composite.In addition,Ibu-Co₉S₈@MoS₂-4 was placed in high temperature and strong light environment to study the stability.The experimental results showed that it had good stability.Finally,the cytotoxicity of mouse bone marrow mesenchymal stem cells（BMSC）was investigated and showed that the cells had no significant toxicity when the concentration of materials less than 30μM.3.In the electrochemical test,the performance of catalyzing OER,HER and water splitting of series Co₉S₈@MoS₂-T samples were evaluated by standard three-electrode system.The results showed that Co₉S₈@MoS₂-4possessed the most efficient catalytic performance in all of Co₉S₈@MoS₂-T samples.For OER,the over potential at the current density of 10 mA cm^-2was only 330 mV in the 1M KOH electrolyte and the corresponding Tafel slope was137 mV dec^-1,which was significantly lower than commercial RuO₂.For HER,the current density of 10 mA cm^-2for Co₉S₈@MoS₂-4 was the smallest in the same electrolyte,which was only 132 mV and the corresponding Tafel slope was 131 mV dec^-1.The required overpotential was closed to commercial Pt/C catalyst.Finally,a two-electrode device with Co₉S₈@MoS₂-4 as anode and cathode was assembled and showed that the current density of 10 mA cm^-2for overall water splitting was only 1.66 V,which was advantageous compared with other non-precious metal monolithic electrocatalyst.It provides theoretical basisa for selecting novel nanostructured inorganic materials as efficient electrocatalyst in the future development.