Transition Metal Nanostructures For Electrochemical Catalysis And Sensing

Diabetes characterized by high blood sugar,is a worldwide health disorder,which can increase the risk of suffering from various diseases endangering human health,such as obesity,atherosclerosis,renal failure,stroke,coronary heart disease and neurological diseases,etc.Therefore,it is necessary to keep blood sugar levels within the normal range(3–8 mmol L^-1),which first requires an accurate and sensitive glucose sensor.Among the various methods for detecting glucose,the non-enzymatic glucose electrochemical detection has been favored by people because of its high sensitivity and wide detection range.Compared with other materials,transition metal sulfides are advantageous to the study of electrochemical sensors due to their unique morphology,structure and abundant electronic channels.In this paper,we studied the application of transition metal sulfides in glucose detection.With the development of society,it is very difficult for traditional fossil energy to meet the growing energy needs,so finding a new energy source to replace the fossil energy is imminent.Various green resources such as solar energy,win energy and tidal energy have been paid close attention,but the contingency of resources is strong and they have low sustainability.Therefore,it is necessary to develop an efficient battery system to convert various unstable resources into the stable electric energy.Among various batteries,lithium-ion batteries have excellent performance.The key factor that affect the performance of lithium-ion batteries is the choice of electrode materials.In addition to energy conversion issues,people are still looking for new clean energy,hydrogen is an ideal and environmentally friendly energy source.It is difficult to obtain hydrogen directly from nature,so solving the problem of producing hydrogen efficiently is on the agenda.In many of processes,the reaction that water electrolyzed was very clean and fast,and the key of process is to find a suitable catalyst.（1）A flower-like N-MoS₂ nanomaterial that assembled from nanosheets was synthesized by one-step hydrothermal method and tested the HER performance in the acidic conditions.When the current density is about 10 mA cm^-2,it shows low overpotential（114 mV）.The structure of the nanosheet is improved obviously when the N element is doped into the MoS₂ nanosheet,the edge effect of the material is enhanced,and the number of active sites is increased in the electrolysis hydrogen evolution reaction.And the material showed excellent stability,the catalytic current remained at about 10mA cm^-2 after 5 hours.After 5000 cycles,the LSV curve can coincide with the first circle,indicating that the nanomaterial has a good durability and strong cycle life.（2）VS₂@CNTs nanocomposites were synthesized by simple one-step hydrothermal method.The negative electrode material of lithium ion batteries was tested for battery performance.Its initial charge and discharge capacities were 460 mAh g^-1and 970 mAh g^-1respectively,and the corresponding coulombic efficiency was 47.4%.When the current density comes to 0.1 A g^-1,the corresponding capacitance is 1133 mAh g^-1.When the current density reaches 2 A g^-1,it still shows a very considerable battery capacity.When the charge and discharge cycles reach about 200 cycles,the capacitance of the material remains in a good stable state.It has been proved that the structure and element composition of the materials were synthesized as the same as we expected by various methods,such as XPS,SEM,TEM,EDS,etc.The new combination of methods has also contributed to the development of anode materials of lithium-ion batteries in the future.（3）NiMoO precursors with rod-like structure were successfully synthesized by reflowing and following calcination at high-temperature.The flexible NiMoS@GO Paper（NiMoS-GP）material was obtained by chemical deposition and one-step hydrothermal method.The morphology,elemental composition and bonding state of composites were verified by SEM,XRD and XPS.The detection of glucose was achieved successfully,the range of detection was from 0.01 mM to 0.8 mM and the minimum limit of detection was 113 nM.The sensor has good anti-interference ability and good stability.In particular,the material is a flexible material,which can be directly used as working electrode for glucose testing,and can meet the detection work in different environments.