Controlled Synthesis Of Low-Dimensional(Hydro)oxide Nickel/Carbon Hybrid Nanomaterials And Their Applications For Glucose Sensing

In recent years, hybrid nanomaterials have found prosperous applications in diversefields, such as catalysis, biology, iatrology, and photoelectromagnetic devices becauseof their peculiar morphologies and structures together with their fascinating physicaland chemical properties. Considering the fact that the synergistic effect has existed inhybrid nanomaterials as demonstrated by previous researches, it is therefore possible todevelop novel functional materials by integrating multicomponent nanoscale entitiesinto hybrid system. In this work, we focused our research on the synthesis of graphene/Ni（OH）₂and NiO/C nanomaterials with low-dimension and their application in glucosesensing. Additionally, the relationships between electrochemical properties and themorphology and structure of the resultant hybrid materials were also discussed.Synthesis and electrochemical performance of graphene/Ni（OH）₂hybrid nanomaterials.In this chapter, we demonstrated a facile method for the preparation of graphene/Ni（OH）₂hybrid nanomaterials. Firstly, azide-terminated poly（vinylpyrrolidone）（PVP-N₃） and alkyne functionalized graphene oxide （AGO） were separately prepared. Thenpolymer functionalized graphene oxide （PGO） was prepared by Cu（I） catalyzed clickcoupling of AGO with PVP-N₃. Subsequently, Ni（OH）₂nanoparticles were depositedonto graphene nanosheets using PGO as a template. Upon reduction with sodiumborohydride, graphene/Ni（OH）₂hybrid nanostructure was constructed. The as-preparedgraphene/Ni（OH）₂hybrid nanosheets were directly immobilized onto the surface ofglassy carbon electrode for glucose determination. This nonenzymatic glucose sensorexhibited a wider linearity range from0.3to750μM with a detection limit of30nM（S/N=3）.Synthesis of Ni（SO₄）_0.3（OH）_1.4/C core‐shell nanobelts. Ni（SO₄）_0.3（OH）_1.4nanobelts havebeen synthesized via a simple template-free hydrothermal reaction in an aqueoussolution containing nickel sulfate and sodium acetate. It is found that the sulfate ions can play a capping agent role in crystal growth and result in anisotropic crystal growthin the dissolution-crystallization process. Under optimized conditions （[Ni2+]=25mM,[Ni2+]/[Ac]=1/4,180oC,48h）, Ni（SO₄）_0.3（OH）_1.4nanobelts have been successfullysynthesized. Subsequently, core-shell Ni（SO₄）_0.3（OH）_1.4/C composite nanobelts havebeen synthesized from the carbonization and polymerization of glucose under a mildhydrothermal condition in the presence of newly produced Ni（SO₄）_0.3（OH）_1.4nanobelt.The shell thickness of the core-shell nanobelts can be varied from2to18nm byadjusting the concentration of glucose ranged from1.125–6.750g/L. In addition, XRD,SEM, TEM, XPS, and FTIR techniques were used to characterize the nanobelts beforeand after carbon deposition.Synthesis of NiO/C core‐shell nanobelts and their applications for glucose sensing. Thestructural evolution from core-shell Ni（SO₄）_0.3（OH）_1.4/C to NiO/C has been performedvia ex situ heat treatment. The influences of heat treatment temperature on the structureand properties of resultant NiO have been systematically investigated. Firstly, thestructural evolution from Ni（SO₄）_0.3（OH）_1.4to NiO has been studied by using FTIR andXRD spectroscopy. Subsequently, the morphology and electrochemical properties havebeen elevated by using SEM, cyclic voltammtery and chronoamperometry. Theas-prepared NiO and NiO/C composites were directly deposited onto the surface ofglassy carbon electrode （GCE） for nonenzymatic glucose determination. Underoptimized conditions, the as-fabricated NiO/GCE sensor exhibited a linearity rangefrom1to170μM glucose with a detection limit of210nM （S/N=3）, while theNiO/C/GCE sensor exhibited a wider linearity range from0.5to180μM glucose witha detection limit of25.5nM （S/N=3）. Additionally, the NiO/C/GCE sensor has beensuccessfully used for the assay of glucose in serum samples with good recovery,ranging from92.9%to98.7%.