Preparation And Field Responses Of Nanosized Recombined Multi-parametric Functional Oxides

Single functional material can not meet the diversity of practical application any more, thus seeking multi-functionalized material is the development tendency of future technology. The realization of multi-functionalization depends on the synergy of internal multiple parameters and external multiple field responses. It will be a great breakthrough to realize the coupling of multiple parameters and application of multi-functionalization in a single phase. Exploring recombined multi-parametric single phase materials, especially above room temperature, is with great practical significance.Layered oxides are the excellent candidates for the recombined multi-parametric single phase materials due to the particular crystal structure. However, before 2009, most of these layered oxides belong to ferroelectric and dielectric system and there is nearly no reports about the recombination of magnetism and electricity above room temperature. In 2009, Mao, Chen, and Lu et al sucessfully manufactured a new single-phase magnetoelectric material Bi-5Fe0.5Co0.5Ti3O15 through a new atomic interlayer embedded method, which exhibited large ferroelectric and ferromagnetic response at room temperature. This work realized the breakthrough of layered oxides materials potential application in quantum function field. Based on the above ideas, Prof. Lu proposed the concept "recombined multi-parametric oxides quantum functional material" in the MOST National Major Scientific Research Projects (2012CB922000). The essence is to materialize the new recombined multi-parametric oxides quantum functional material with magnetoelectricity modulated "recombined" structure within the cell and "recombined" ordered phase through new atomic interlayer embedded method. Developing more recombined multi-parametric oxides quantum functional materials is important to expand the quantum multifunctional material system, to enhance the recombination and regulation if quantum multi-function, to discover new mechanism of quantum regulation and theory of recombination.Given the advantages of structure and property of recombined multi-parametric oxides quantum functional materials, to realize more external field response via some new technology and methods will greatly enrich the multi-functionalized applications of quantum oxide functional materials. In this work, taking explorion of new recombined multi-parametric oxide materials as the key, we design the structure and composite of low dimensional materials and investigate external field responses of the nanosized recombined multi-parametric oxide materials, such as multiferroic, photocatalytic activity, sonocatalytic activity, photoluminence and so on.The original work of this paper as follows:Part 1, taking synthesis of nanostructured Bi7Fe3Ti3O21 (BFTO) as the key, investigate the multiferroic property and photocatalytic activity of low dimensional multi-parametric oxide materials. By adjusting the crystal growth time and concentration of mineralizer, the nanoshelf-like BFTO were obtained. For the first time, the photocatalysis was reported for this specific naosized BFTO together with improved multiferroic property compared with bulk form. This finding suggested an effective approcach of enhancing the visible light photocatalysis by the recombination of electric polarization and photocatalytic property.Part 2, base on the above work, the BFTO was modified by atomic interlayer embedded method to realize improved room-temparature multiferroic property, to broaden sun light spectrum response and to resolve recycling problem of small particals. Finally, the cutoff wavelength of light absorption was red-shifted from 560 nm to beyond 800 nm NIR range, and the magnetic ground state of doping samples were ferromagnetic while antimagnetic for undoping one at room temperature. The magnetism of this kind of multi-parametric nanosized photocatalyst makes it convenient to recyle from the suspension under an external magnetic field.Part 3, the ultrasound induced organic pollutant decomposition under the acoustic field response of multi-parametric nanosized catalyst was studied carefully. Also, a possible mechanism of pollutant decomposition under acoustic field was proposed:electric surface charge will be generated under the vibration of acoustic field; redox reactions will be triggered when there is enough charge accumulation, which will degradate the organic dye moleculor into carbon dioxide and water. The recombination of acoustic field response and magnetism indicates a new direction of solving environment and energy problem.Part 4, we tried to explore the photoluminence of multi-parametric nanosized functional materials by doping rare earth elements. Advanced technique was applied to control the morphology and size of nanoparticles, and this kind of nanoparticals was used to verify the biological compatibility and security this multi-parametric nanosized functional materials. This study broadened the application prospects of this kind of materials in the intergration of biological targets, imaging, diagnosis and treatments.Part 5, taking advantage of self-template characteristic of multi-parametric oxide nano-plates, highly grain-orientated bulk materials were successfully prepared with magnetic anisotropy. The grain-orientated ceramics is more reflective in the anisotropy of this kind of layered materials compared to traditional countparts.