Preparation And Performance Of Flower-like Silica And Titania

In this study,flower–like yolk–shell SiO₂ nanospheres?FYSSns?and flower–like mesoporous TiO₂ hierarchical spheres?FMTHSs?with ordered stratified structure were prepared using solvothermal methods.The morphology and structure of materials were controllable.The possible mechanisms were proposed through a series of analysis.The obtained materials were applied to electrochemical sensing and lithium-ion battery applications,respectively.We developed a facile one–pot strategy for fabricating FYSSns using cetyltrimethylammonium bromide?CTAB?–polyvinylpyrrolidone–cyclohexane–ethanol–water vesicle–microemulsion composite aggregation as templates through a simple solvothermal route.FYSSns displayed yolk–shell structures with flower–shaped yolks?260–320 nm?with ordered radial mesochannels??7 nm?,large cavities?100–120 nm?,and thin silica shells?20–30 nm?.High laccase immobilization amounts(906.67 mg g^–1)were achieved using FYSSns as supporter,and the laccase–modified FYSSns were applied to the electrochemical sensor with high selectivity for detecting catechol.Under the optimized conditions,the proposed sensor showed a wide linear range from 12.5–450?M over catechol concentration and a low detection limit of 1.6?M.The outstanding performance was attributed to the advantages of FYSSns,such as large specific surface area and its own mesochannel structure.FMTHSs with ordered stratified structure and TiO₂ nanoparticles?TNPs?were synthesized via a facile solvothermal route and an etching reaction.Multilamellar vesicles?MTSVs?and unilamellar TiO₂/SiO₂ vesicles?UTSVs?were prepared using CTAB and didodecyldimethylammonium bromide as structure–directing agents under different solvothermal conditions.The MTSVs were formed at low solvothermal temperatures?100°C and 130°C?.After etching reaction,the flower–like mesoporous TiO₂ hierarchical spheres?FMTHSsm?were obtained.FMTHSsm are assembled by petals with ordered stratified structures.At a high solvothermal temperature?160°C?,UTSVs were obtained,and TiO₂ nanoparticles?TNPs?were obtained after etching reaction.Compared with other morphologies of TiO₂,the flower–like TiO₂ obtained in this experiment has an ordered layered structure,which greatly increases the specific surface area of the particles,and this layered structure provides a possibility for the storage of guest molecules.FMTHSs display flower–like,ordered stratified structures on each petal.The thickness of the ordered stratified structure is approximately 3–6 nm,and the number of layers is approximately 2–4.The FMTHSs2 electrode exhibits the first discharge capacity of212.4 mA h g^-1 at 0.2 C,which is higher than that of TNPs electrode(167.6 mA h g^-1).The discharge specific capacity of FMTHSs2 electrode after 200 cycles at 1 C is105.9 mA h g^-1,which is higher than that of TNPs electrode(52.2 mA h g^-1)after the same number of cycles.The outstanding performance of FMTHSs2 electrode is attributed to the advantages of FMTHSs.In particular,their own stratified structure can provide additional active sites for reactions.The hierarchical structure can provide short diffusion length for Li⁺,large electrolyte–electrode contact area,and superior accommodation of the strain of Li⁺intercalation/deintercalation.