39 results about "Bismuth ferrite" patented technology

The invention provides a bismuth ferrite-graphite phase carbon nitride photocatalyst and a preparation method and application thereof, and relates to the technical field of photocatalysis, the preparation method comprises the following steps: dissolving a bismuth source and an iron source in a solvent, mixing with a mineralizing agent, and carrying out a hydrothermal synthesis reaction to obtain bismuth ferrite; performing first roasting treatment on the nitrogen-containing organic matter precursor to obtain graphite-phase carbon nitride; and mixing bismuth ferrite and graphite phase carbon nitride, and carrying out grinding treatment and second roasting treatment to obtain the bismuth ferrite-graphite phase carbon nitride photocatalyst. According to the preparation method, bismuth ferrite and graphite-phase carbon nitride which are prepared respectively are compounded, a Z-type heterojunction can be constructed at an interface of the bismuth ferrite and the graphite-phase carbon nitride, an internal electric field is formed, so that photo-induced electrons and holes are efficiently separated, compounding of the photo-induced electrons and the holes is effectively inhibited, and finally the oxidation-reduction capacity of the material is remarkably enhanced; therefore, the photocatalyst shows excellent photocatalytic performance, high selectivity and good cycle stability.

The application discloses a magnetoelectric heterojunction film and a preparation method thereof. The magnetoelectric heterojunction film comprises a strontium titanate base layer, a strontium ruthenate electrode layer, a bismuth ferrite ferroelectric material layer and a SmCo-based ferromagnetic material layer which are stacked in sequence. The magnetoelectric heterojunction film has the multi-ferroelectric layer room-temperature magnetoelectric coupling effect and the excellent magnetic performance of the ferromagnetic layer, and the magnetoelectric coupling effect of the heterojunction film can be enhanced through the strong exchange bias effect at the interface.

The invention discloses pure-phase bismuth ferrite-strontium titanate ceramic as well as a preparation method and application thereof, and belongs to the field of lead-free ferroelectric ceramic. Comprising the following steps: filling pure-phase BFO-STO precursor powder prepared by a hydrothermal method into a graphite mold, controlling the heating rate to a sintering temperature, and sintering under the conditions of external pressure and heat preservation, so as to finally prepare the BFO-STO ceramic. The BFO-STO ceramic is prepared through SPS sintering, volatilization of Bi < 3 + > and generation of impure phases are effectively inhibited, ferroelectric, dielectric and magnetic properties of the BFO ceramic are effectively improved, and possibility is provided for practical application of the BFO-STO ceramic in the fields of functional sensors, magnetic memories, piezoelectric generators, high-temperature inductors and the like.

The application discloses a kind of bismuth ferrite-barium titanate textured piezoelectric ceramics and preparation method thereof, belong to ceramic preparation technical field, the preparation method includes: with (001) crystal direction BaTiO3 flaky microcrystal as template, with (1-x) BiFeO3-xBaTiO3 ceramic matrix powder is mixed, through casting process, matrix powder is grown along the template crystal direction, during, by controlling the amount of BaTiO3 flaky microcrystal, so that the volume ratio of it and ceramic matrix powder does not exceed 0.06, the thickness of casting film is 30~50 μm, and high-temperature sintering and high-temperature quenching mode with temperature up to 970 ℃~1040 ℃ is used, finally form textured BF-BT ceramic, the formed ceramic has good piezoelectric property and texture degree, and the above method process is simple, without adding additional material.

This invention relates to the field of wastewater treatment technology, specifically to a metal-doped bismuth ferrite-based perovskite composite material, its preparation method, and its applications. The molecular formula of the metal-doped bismuth ferrite-based perovskite composite material is Bi. 1‑x A x Fe 1‑y B y O3; 0 ≤ x < 1, 0

The invention discloses a heat treatment method of high-polarization-intensity bismuth ferrite-lead titanate-barium zirconate titanate based ferroelectric ceramic, which comprises the following steps: arranging an electrode on the surface of a bismuth ferrite-lead titanate-barium zirconate titanate based ferroelectric ceramic sintered body, and then putting the sintered body into a rapid annealing furnace; the preparation method comprises the following steps: heating to 550-650 DEG C from room temperature at a heating rate of 5-80 DEG C / s, carrying out heat preservation for 45-75 seconds, carrying out first rapid annealing, and cooling to room temperature at a cooling rate of 250-350 DEG C / s, thereby obtaining the bismuth ferrite-lead titanate-barium zirconate titanate based ferroelectric ceramic. The heat treatment method provided by the invention can rearrange defects in the ceramic, increase domain conversion switches, improve the performance of the ceramic, and improve the performance of the ceramic. Furthermore, the ferroelectric piezoelectric property of the polarized BF-PT-BZT ceramic is greatly improved, and meanwhile, the polarized BF-PT-BZT ceramic has high Curie temperature.

The application provides a BiFeO3-graphitic carbon nitride photocatalyst and a preparation method and application thereof, relates to the field of photocatalysis technology, and the preparation method comprises the following steps: dissolving a bismuth source and an iron source in a solvent, mixing with a mineralizer, and performing a hydrothermal synthesis reaction to obtain BiFeO3; performing first calcination treatment on a nitrogen-containing organic precursor to obtain graphitic carbon nitride; and performing grinding treatment and second calcination treatment on the mixture of BiFeO3 and graphitic carbon nitride to obtain the BiFeO3-graphitic carbon nitride photocatalyst. The preparation method can construct a Z-type heterojunction at the interface of the separately prepared BiFeO3 and graphitic carbon nitride, form an internal electric field, efficiently separate photo-generated electrons and holes, effectively inhibit the recombination of the photo-generated electrons and holes, finally significantly enhance the redox capacity of the material, and make the material exhibit excellent photocatalytic performance, high selectivity and good cycle stability.

The invention discloses a texture preparation method for high-performance lead-free piezoelectric ceramics of bismuth ferrite-barium titanate. The general formula of the ceramic composition is as follows, where the molar fraction ratio of BiFeO3 and BaTiO3 is 2:1, x, y, t, and m all represent molar fractions, and 0 < x ≤ 0.05, 0 < y ≤ 0.05, 0 < t ≤ 0.05, 0 < m ≤ 0.05. In the sintering stage of the invention, a temperature gradient field is constructed to make the ceramic grains grow texture-directionally, and a textured piezoelectric ceramic with a piezoelectric constant d 33 reaching above 1000 pC / N at 350 °C and a T dr reaching above 350 °C is obtained. The preparation process of the invention is simple, and the prepared ceramic has excellent high-temperature performance and can be applied to the field of high-temperature piezoelectricity.

The invention discloses a preparation method of a functionalized palladium quantum dot loaded bismuth ferrite nanorod piezoelectric catalytic hydrogen evolution material, and belongs to the technical field of new energy catalytic materials. According to the invention, a palladium quantum dot loaded bismuth ferrite nanorod (Pd-BFO) cocatalyst is constructed by a simple method of electrostatic spinning and chemical reduction. The material can be used as a mechanical energy and chemical energy conversion platform and is used for efficient piezoelectric catalytic hydrogen evolution reaction. Under ultrasonic irradiation, the strong piezoelectric response of bismuth ferrite can induce ferroelectric polarization, and a built-in polarization field is formed to separate charges. Palladium quantum dots serve as a cocatalyst, transfer and enrichment of polarized charges can be promoted, the charge separation efficiency is improved, meanwhile, water adsorption and hydrogen desorption energy barriers are optimized, and therefore the piezoelectric catalytic hydrogen evolution activity is remarkably improved. The 0.5 wt% Pd-BFO material obtained through optimization can achieve the excellent hydrogen evolution rate of 4253.44 [mu] mol.g <-1 >. H <-1 >, and the performance of the Pd-BFO material is superior to that of most reported piezoelectric catalysts at present.

The invention discloses a microwave hydrothermal preparation method of a BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction multiferroic material. The microwave hydrothermal preparation method comprises the following steps: 1) preparing an oxyhydroxide precipitate suspension containing iron and cobalt; (2) adding bismuth ferrite single crystal nanosheets and a mineralizer into the suspension prepared in the step (1), and uniformly stirring to obtain a reaction material; (3) transferring the reaction material prepared in the step (2) into an inner container of a microwave reaction kettle, adjusting the volume of the reaction material in the inner container of the reaction kettle to 70-90% of the volume of the inner container of the reaction kettle by using deionized water, and uniformly stirring; (4) putting the microwave reaction kettle inner container into a microwave reaction kettle, putting the microwave reaction kettle into a microwave hydrothermal instrument for microwave hydrothermal treatment, raising the temperature to 200-240 DEG C in a staged temperature raising manner, and keeping the temperature for 5-2 hours; and 5) after the microwave hydrothermal reaction is completed, naturally cooling the microwave reaction kettle to room temperature, repeatedly washing a reaction product with deionized water and absolute ethyl alcohol, filtering and drying to obtain the BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction multiferroic material.

This application belongs to the interdisciplinary fields of semiconductor optoelectronic devices, multiferroic materials, and neuromorphic computing. Specifically, it discloses an in-situ differential optoelectronic synaptic device and its in-memory computing method. The method involves grounding the first and second electrodes, applying a voltage to the bottom electrode to change the polarization direction of the ferroelectric domains in the bismuth ferrite thin film, and using the polarization direction of the ferroelectric domains as the weight symbol in the neural weights to set the non-volatile synaptic weights. The voltage on the bottom electrode is then removed or reduced, and a light spot is used to illuminate the bismuth ferrite thin film. By adjusting the position of the light spot, the differential current between the first and second electrodes is read and used as the weight value in the neural weights, thus realizing the read operation. This application achieves integrated storage and computing.

This piezoelectric film substrate 100 comprises a substrate 1, a seed layer 2, a lower electrode layer 3, an adjustment layer 4, a piezoelectric layer 5, and an upper electrode layer 6. The seed layer 2 contains a zirconium oxide formed by an epitaxial growth layer on the substrate 1 composed of a (100) silicon single crystal. The lower electrode layer 3 contains at least one among iridium and platinum formed by an epitaxial growth layer on the seed layer 2. The adjustment layer 4 contains a metal oxide having a perovskite structure formed by an epitaxial growth layer on the lower electrode layer 3. The piezoelectric layer 5 is composed of bismuth ferrite preferentially oriented to (100) on the adjustment layer 4.

The invention relates to a high-temperature self-stabilization ferroelectric domain wall memory based on bismuth oxide (BFO) and a preparation method thereof, a memory function layer is formed by sequentially depositing an STO buffer layer with the thickness of 5 nm, a BFO film with the thickness of 100 nm and a planar Pt electrode pair on a strontium titanate (STO) substrate in the [001] direction, the STO substrate is obliquely cut by 0.2 degree in the [100] direction, the BFO film is of a stripe domain structure, and the electrode gap is not smaller than 500 nm. Through the limiting effect of a beveled substrate step, the BFO ferroelectric film only forms two polarization orientations, a periodic stripe domain structure is obtained, the polarization overturning controllability is improved, the electrode is prepared by adopting an electron beam photoetching and ion etching combined process, the electric domain overturning is ensured to penetrate through the film thickness, and the performance of the BFO ferroelectric film is improved. After 105 times of voltage pulse cycles at a high temperature of 135 DEG C, the device still keeps a rectification ratio greater than or equal to 25: 1, the turnover polarization retentivity is high, and the domain wall current attenuation rate is small. The bottleneck that a traditional FeRAM fails in a high-temperature environment is broken through, the storage density potential is larger than 1 Gb, and the FeRAM has the effect of being suitable for high-temperature application scenes such as aerospace, vehicle-mounted electronics and geothermal exploration.

This invention relates to electronic material development and thin film material preparation technology, specifically to a bismuth ferrite film material, its preparation method, and its applications. The preparation method includes: sequentially magnetron sputtering a bottom electrode, a bismuth ferrite film, and a top electrode onto a silicon substrate surface from bottom to top; wherein the bottom and top electrodes are made of inert metals; the gas atmosphere for magnetron sputtering the bottom electrode is a mixture of argon and oxygen, and the magnetron sputtering temperature is 200–400°C; the gas atmosphere for magnetron sputtering the bismuth ferrite film is a mixture of argon and oxygen, and the magnetron sputtering temperature is 300–500°C; the gas atmosphere for magnetron sputtering the top electrode is argon, and the magnetron sputtering temperature is 25–150°C. The bismuth ferrite film material provided by this invention, by adjusting the gas atmosphere during bottom electrode sputtering, changes the growth orientation of the bismuth ferrite material, thereby improving the overall piezoelectric properties of the bismuth ferrite film material. It eliminates the need for a buffer layer, doping with any elements, or high-temperature annealing, making the preparation method simpler.

This invention discloses a doped and modified bismuth ferrite-based heterojunction and its application in the photocatalytic degradation of organic wastewater. The doped and modified bismuth ferrite-based heterojunction is prepared through the following steps: S1, preparing carboxylated graphene oxide; S2, preparing acousto-optic dual-response carbon dots; S3, preparing the doped and modified bismuth ferrite-based heterojunction via a hydrothermal method. This invention significantly enhances the photocatalytic activity of the bismuth ferrite-based heterojunction by using rare earth gadolinium, carboxylated graphene oxide, and acousto-optic dual-response carbon dots for co-doping. The introduction of acousto-optic dual-response carbon dots endows the doped and modified bismuth ferrite-based heterojunction with catalytic activity under ultrasonic irradiation, enabling it to achieve higher wastewater degradation efficiency when used for organic wastewater treatment under both visible light and ultrasonic irradiation.

The application relates to the technical field of dielectric energy storage device materials, in particular to a high-entropy design bismuth ferrite-based energy storage ceramic, a preparation method and application thereof, the material has a chemical composition formula of (0.7-x)Bi 0.9 (Sm 0.5 Gd 0.5 ) 0.1 FeO3-0.3(Sr 0.5 Ba 0.5 )TiO3-xNaNbO3-yMnO2, wherein the value range of x is 0-0.15, and the value of y is 0-0.005. The application adopts a high-entropy strategy to design a relaxor ferroelectric material, multiple elements occupy the same site of the material to produce lattice distortion, promote the relaxor characteristics of the bismuth ferrite-based ceramic, and optimize the electric hysteresis loop. The NaNbO3 antiferroelectric material is introduced to destroy the long-range ferroelectric order and enhance the local random field, which is beneficial to obtaining a lower P r value. In addition, the appropriate addition of 0.5% mol of MnO2 can reduce the concentration of oxygen vacancies, thereby reducing the leakage current of the material, and the energy storage efficiency is improved. The material design not only enriches the application field of high-entropy ceramics, but also provides a new idea for improving the performance of energy storage ceramics.

The invention discloses pure-phase bismuth ferrite ceramic as well as a preparation method and application thereof, and belongs to the field of lead-free ferroelectric ceramic. Comprising the following steps: putting pure-phase bismuth ferrite precursor powder prepared by a hydrothermal method into a graphite mold, controlling the heating rate, heating to a sintering temperature, applying pressure, keeping the temperature, sintering, and finally preparing the pure-phase bismuth ferrite ceramic. According to the pure-phase bismuth ferrite ceramic prepared through SPS sintering, volatilization of Bi < 3 + > and generation of impure phases are effectively inhibited. The bismuth ferrite ceramic shows good magnetic performance, the magnetic performance is enhanced, good dielectric stability is shown, and the bismuth ferrite ceramic has certain ferroelectricity and good energy storage performance. Aiming at the problems that pure-phase bismuth ferrite ceramic is difficult to prepare by a traditional solid-phase reaction method, a mixed phase is generated due to Bi < 3 + > volatilization and oxygen vacancy defects caused by high-temperature sintering, multiferroic performance is unstable and the like, the preparation process of the bismuth ferrite ceramic is optimized by adopting a mode of combining a hydrothermal method and spark plasma sintering (SPS).

The invention discloses a high-performance bismuth ferrite film capable of being driven by low voltage. The high-performance bismuth ferrite film comprises a substrate, a conductive oxide buffer layer and a bismuth ferrite-based film layer, wherein the conductive oxide buffer layer and the bismuth ferrite-based film layer are spin-coated on the surface of the substrate; the thickness of the conductive oxide buffer layer is 100-350 nm; the bismuth ferrite-based thin film layer is obtained by coating the conductive oxide buffer layer with precursor sol containing bismuth, iron and doping elements and performing crystallization heat treatment; the crystallization heat treatment comprises a stage of rapidly heating to crystallization temperature and a stage of controlled slow cooling. According to the prepared film, the coercive voltage of the BiFeO3 film can be remarkably reduced, and meanwhile, the piezoelectric coefficient of the BiFeO3 film is effectively improved, so that the comprehensive piezoelectric property of the film is improved.

The invention discloses a preparation method of a multi-element co-doped bismuth ferrite film system material, the film material is Bi < 1-x > (La < 0.2 > Nd < 0.2 > Sm < 0.2 > Gd < 0.2 > Lu < 0.2 >) < x > FeO < 3 >, and x is equal to 0.05, 0.1, 0.14 and 0.2. According to the preparation method, a multi-element co-doped ceramic target material is prepared by adopting a sol-gel method, and then the multi-element co-doped bismuth ferrite film is epitaxially grown on a LaAlO3 substrate by adopting a pulse laser deposition technology. According to the preparation method, uniform doping of five rare earth elements (La, Nd, Sm, Gd and Lu) in BFO crystal lattices is achieved, the prepared ceramic target material is high in density, and an epitaxial film is high in purity and good in crystallinity. The phase structure, ferroelectricity and conductivity of the film are remarkably regulated and optimized through the multi-element co-doping effect, compared with a pure-phase bismuth ferrite film, the coercive field of the film is remarkably reduced, the conductivity is improved by several orders of magnitude, and meanwhile the film has a regular nano island structure and an excellent ferroelectric domain overturning characteristic. The thin film prepared by the method is suitable for next-generation nonvolatile memories, sensors and multifunctional electronic devices.

The present invention provides a high-strain bismuth ferrite-based lead-free piezoelectric ceramic and a preparation method thereof, which is represented by the composition general formula (1-x-y)BiFeO3-xBaTiO3-yM, where 0.25 < x < 0.35 and 0.005 < y < 0.08; the dopant M is selected from BaHfO3, CaSiO3, MgSiO3, BeSiO3, SrSiO3, SrSnO3, BiYO3, SbYO3, SbGaO3, BiYO3, YGaO3 or LaAlO3. The bismuth ferrite-based lead-free ceramic material of the present invention has excellent density (>95%), high strain performance, high Curie temperature and other characteristics. At the same time, the solid-phase sintering process technology adopted by the present invention is simple in operation and low in cost, suitable for mass production, and the prepared bismuth ferrite-based ternary system lead-free ceramic material can be used as a dielectric material for multilayer ceramic brakes.

The invention relates to the technical field of piezoelectric ceramic material preparation, and discloses a bismuth ferrite-barium titanate textured piezoelectric ceramic material with low sintering temperature and high piezoelectric property and a preparation method thereof, and the preparation method comprises the following steps: preparing a bismuth ferrite precursor template with copper oxide loaded on the surface; dispersing the template, barium titanate, bismuth oxide powder and a hyperbranched polyesteramide dispersing agent into photosensitive resin to prepare slurry; performing slip casting and in-situ photocuring under a static strong magnetic field; and carrying out glue discharging and reactive sintering to obtain a target product. An interface liquid phase is formed at the initial stage of sintering by using copper oxide on the surface of the template, and template particles are anchored through capillary force, so that template deflection in the densification process is inhibited, and the ceramic texture degree is improved; meanwhile, bismuth volatilization is inhibited through liquid-phase-assisted low-temperature sintering, the leakage current of the material is reduced, and the prepared ceramic has a high piezoelectric constant, a high Curie temperature and good insulativity.

The application relates to a bismuth ferrite-indium zinc sulfide-silver composite catalyst driven by ultrasonic and visible light, and a preparation method and application thereof, wherein the preparation method comprises the following steps: S1. hollow bismuth ferrite core preparation: taking bismuth nitrate and iron nitrate as raw materials, adding a solvent, heating to obtain a precursor powder, calcining the precursor powder to obtain a crude product, and washing and drying the crude product to obtain the hollow bismuth ferrite core; S2. shell-core type bismuth ferrite-indium zinc sulfide heterojunction preparation: taking zinc chloride, indium chloride and thioacetamide as raw materials, adding a solvent, adding the hollow bismuth ferrite after mixing, dispersing, heating and reacting to obtain the shell-core type bismuth ferrite-indium zinc sulfide heterojunction; and S3. composite catalyst preparation: dispersing the heterojunction powder into a solvent, adding silver nitrate, mixing in the dark, heating and reacting, collecting the precipitate, washing and drying the precipitate, heating and stirring the precipitate in acetone, filtering, and drying to obtain the composite catalyst. The composite catalyst can form an inner core piezoelectric field, a heterojunction interface and an outer layer Mott-Schottky potential barrier, realizes ultrasonic and visible light dual-energy driving, activates persulfate and degrades organic pollutants.

This invention discloses the preparation and application of a porous bismuth ferrite material. The preparation method includes the following steps: dissolving bismuth and iron salts in an acid solution to obtain a metal solution; adding a complexing agent and a pore-forming agent to the metal solution and mixing to obtain a precursor solution; heating the precursor solution to obtain a wet gel; drying the wet gel to obtain a dry gel; and calcining the dry gel under an inert atmosphere containing 6-10% oxygen to obtain the porous bismuth ferrite material. The porous bismuth ferrite electrode material of this invention not only solves the structural defects of traditional porous bismuth ferrite materials, such as small pore volume and insufficient utilization of active sites, but also fully utilizes its membrane capacitance characteristics and bimetallic synergistic effect, showing excellent application prospects in the field of capacitive deionization and chlorine removal.

The invention discloses bismuth ferrite-based energy storage ceramic, a preparation method thereof and an energy storage device, and belongs to the field of energy storage ceramic materials, and the bismuth ferrite-based energy storage ceramic comprises the following chemical components: 1 / 3 BiFeO3-1 / 3 BaTiO3-1 / 3 Ca0. 5Sr0. 5TiO3-xwt% of a sintering aid, wherein 0 lt; x is less than or equal to 6, and the sintering aid comprises at least one of CuO, MgO and MnO2. On the basis of the existing bismuth-ferrite-based energy storage ceramic, the performance such as energy storage density of the bismuth-ferrite-based energy storage ceramic is remarkably improved by optimally designing the chemical composition of the bismuth-ferrite-based energy storage ceramic and introducing a proper amount of sintering aid, and the low-temperature high-entropy bismuth-ferrite-based energy storage ceramic is obtained. The practical application of the bismuth ferrite-based energy storage ceramic in the fields of pulse power technology, power electronic system and the like is powerfully promoted.

Disclosed in the present invention are an organism and a method for promoting the directional growth thereof. The organism comprises at least one of a single cell, a multicellular body, a tissue and an organoid. The method comprises the step of subjecting the organism to a strong-to-weak gradient electric field environment. In the present invention, a layered material is constructed using strontium titanate as a substrate, strontium ruthenate as a regulating layer, and bismuth ferrite as an internal electric domain polarization layer. A surface potential, i.e., a gradient electric field, is generated by the layered material so as to guide the directional growth of the organism in vitro, thereby constructing an organoid that highly mimics the morphology, structure and function of a corresponding tissue in vivo.

This invention discloses a bismuth ferrite / bismuth vanadate photo-Fenton catalyst, its preparation method, and a wastewater treatment device, belonging to the field of wastewater treatment technology. This invention prepares the bismuth ferrite / bismuth vanadate photo-Fenton catalyst via a sol-gel method, which can solve the problem of Fe in traditional Fenton technology. 3+ / Fe 2+ In addition to addressing the technical problem of cyclic obstruction, the photo-Fenton catalyst of this invention has the characteristic of wavelength-selective degradation, which can generate different active species under light conditions with wavelengths <450nm and wavelengths >600nm respectively, thereby achieving segmented and efficient removal of different types of pesticides such as imidacloprid, paraquat, carbofuran, and methomyl from wastewater.

The invention relates to preparation of a bismuth ferrite / strontium titanate nano composite material and application of the bismuth ferrite / strontium titanate nano composite material in the field of piezoelectric light concerted catalysis. Compared with pure-phase BiFeO3 and SrTiO3, the bismuth ferrite / strontium titanate nano composite material synthesized by a coprecipitation method has the advantages that the utilization efficiency of the composite material in the whole sunlight spectrum range is greatly improved, and a remarkable light effect is shown. Under the synergistic effect of ultrasound and light, the bismuth ferrite / strontium titanate nanocomposite can achieve efficient degradation of rhodamine B and remarkable improvement of hydrogen production efficiency, the degradation rate constants are 11.12 times and 7.63 times of those of pure-phase BiFeO3 and SrTiO3 respectively, and the hydrogen production efficiency is 2.21 times and 1.87 times of those of pure-phase BiFeO3 and SrTiO3 respectively. The two materials have good piezoelectric electro-catalytic performance, and generate a built-in electric field under the action of ultrasound, so that the separation efficiency of electron-hole pairs is improved. The invention discloses a method for improving the production of hydrogen by degrading rhodamine B and decomposing water by the material by constructing the heterojunction, and the method is simple in process flow, high in operability and wide in application prospect.

This invention belongs to the field of functional materials and gas sensing, specifically disclosing a method for preparing a bismuth ferrite gas sensor and its application. The method employs gradient annealing, placing the bismuth ferrite sample in a series of atmospheres with continuously increasing oxygen partial pressures, ranging from zero oxygen partial pressure to 100% oxygen partial pressure. The oxygen vacancy concentration, ferroelectric domain order, and gas-sensing performance of the sample after annealing are measured, establishing a correlation between oxygen partial pressure, oxygen vacancy concentration, ferroelectric domain order, and gas-sensing performance, thereby improving the gas-sensing properties of the material. This invention also provides the application of this method in the preparation of bismuth ferrite gas sensors. The above method can maximize the sensor's sensitivity.

This application provides a magnetovoltage electro-photocatalyst, its preparation method, and its application. The magnetovoltage electro-photocatalyst comprises a core and a shell coating at least a portion of the surface of the core. The core material includes A-site doped bismuth ferrite, B-site doped bismuth ferrite, or AB-site co-doped bismuth ferrite. The shell material includes TiO2. The chemical formula of the A-site doped bismuth ferrite is (Bi... 1‑x Na x )FeO3, 0<x≤0.99; the chemical formula of the B-site doped bismuth ferrite material is Bi(Fe 1‑y Mn y O3, 0 < y ≤ 0.99, M element includes one or more of Mn and Co; the chemical formula of the AB site co-doped bismuth ferrite material is (Bi 1‑a Na a (Fe) 1‑b M b O3, 0 < a ≤ 0.99, 0 < b ≤ 0.99. This magnetovoltage electro-photocatalyst exhibits high magnetovoltage electro-photocatalytic efficiency.

The invention belongs to the technical field of inorganic functional film materials, and particularly relates to a bismuth ferrite film and a preparation method thereof. The chemical general formula of the bismuth ferrite film is Bi (1 + Z) Fe (1-X) SbXO3, X is the molar weight of an Sb element, 0.08 < = X < = 0.20, the element Bi is excessively added, the film has N layers, in the first layer to the second layer, 0.05 < = Z < = 0.08, 0.08 < = X < 0.15, in the third layer to the (N-2) th layer, Z is more than 0.10 and < = 0.15, 0.15 < = X < = 0.20, in the (N-1) th layer to the Nth layer, 0.15 < = Z < = 0.20, and 0.12 < = X < 0.18. The bismuth source is bismuth nitrate, the iron source is ferric nitrate, and the antimony source is antimony acetate. The antimony-doped bismuth ferrite film has high orientation preferential degree and excellent ferroelectric performance, and the preparation method is low in cost and easy to operate.