50 results about "Bismuth titanate" patented technology

The invention discloses a strontium-doped bismuth titanate-based ferroelectric film and a preparation method thereof, and belongs to the technical field of dielectric energy storage materials. The chemical composition of the film is Ba < 1-x > Sr < x > Bi < 4 > Ti < 4 > O < 15 >, wherein x ranges from 0.025 to 0.1. The preparation method comprises the following steps: mixing ethylene glycol monomethyl ether and ethylene glycol, adding bismuth nitrate, barium acetate, strontium acetate and butyl titanate, fully stirring and filtering to obtain a precursor solution, aging, dripping to the center of a substrate for spin coating, heating a spin-coated sample to obtain a dry film, and annealing to obtain the ferroelectric film. The method is low in technological condition requirement, and the thin film obtains the optimal energy storage density by changing the doping proportion of Sr. According to the ferroelectric film, when x is equal to 0.075, the leakage current density of Ba0. 925Sr0. 075Bi4Ti4O15 (BBST75) is only 1.59 * 10 <-7 > A / cm < 2 >, the breakdown field strength is as high as 3.22 MV / cm, and at the moment, the film has the energy storage density of 28.2 J / cm < 3 > and the energy storage efficiency of 80.36%.

The invention relates to the technical field of piezoelectric ceramics, in particular to a bismuth ferrite-lead titanate-zinc bismuth titanate ternary system piezoelectric ceramic material as well as preparation and application thereof. The chemical general formula of the bismuth ferrite-lead titanate-zinc bismuth titanate ternary system piezoelectric ceramic material disclosed by the invention is (1-x-y) BiFeO3-x (PbMez) TiO3-yBi (Zn0. 5Ti0. 5) O3, wherein Me is an alkaline earth metal element, x is equal to 0.4-0.8, y is equal to 0.05-0.3, z is equal to 0.05-0.5, and 1-x-y is greater than 0. The piezoelectric ceramic material has large anisotropy (d33 / d31 is between 5 and 60) and relatively high voltage (d33 is greater than 100pC / N), has a wide application prospect in the technical field of high-frequency image sonar transducers, and solves the problems of low piezoelectric coefficient and piezoelectric anisotropy of the existing bismuth ferrite-lead titanate-zinc bismuth titanate ternary system piezoelectric ceramic material.

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 application discloses a low-loss high-Curie-point bismuth ferrite-barium titanate lead-free piezoelectric ceramic material and a preparation method thereof. 1.02 FeO3-(0.25-x)BaTiO3-xCaZrO3+y%GeO2+z%MnO2; wherein x, y and z represent molar fractions, 0.005<=x<=0.020, 0.3<=y<=1, 0.5<=z<=1.5. The application introduces the third component CaZrO3, and adds GeO2 and MnO2, controls the crystal phase composition and the conductive carrier concentration, improves the microstructure, reduces the loss and improves the temperature stability, so that the Curie temperature, the depolarization temperature and the piezoelectricity are obviously improved. The lead-free piezoelectric ceramic material provided by the application has a simple synthesis process, and is expected to be applied to the preparation of high-temperature piezoelectric sensor devices.

The application discloses a Bi4Ti3O12 nanosheet piezoelectric catalyst and a preparation method and application thereof. Bi(NO3)3*5H2O, Ti(OC4H9)4 and Ta2O5 are used as raw materials to prepare a precursor through co-precipitation, NaCl and KCl are used as molten salts to mix the precursor, and then ball milling is carried out, the obtained powder after the ball milling is dried, and then a molten salt reaction is carried out, so that the product is obtained, and after washing and drying, the Bi4Ti3O12 nanosheet piezoelectric catalyst is obtained, and is successfully applied to piezoelectric catalytic degradation of rhodamine B. The prepared Bi4Ti3O12 nanosheet piezoelectric catalyst is a nanosheet with high purity and good crystallinity, and a high-activity exposed surface is beneficial to improving the transmission and separation of photo-generated charges, improving the piezoelectric catalytic performance of the Bi4Ti3O12 nanosheet piezoelectric catalyst, and the preparation process is simple.

The present invention relates to a bismuth titanate niobate-based relaxor ferroelectric ceramic material for energy storage, a preparation method thereof and an application thereof. The relaxor ferroelectric ceramic material has the general formula Bi 3‑x La x TiNbO9, 0≤x≤1.1; this relaxor ferroelectric ceramic material is prepared by lanthanum-doping Bi3TiNbO9 using a solid-phase sintering method; the lanthanum doping is performed with lanthanum oxide. The present invention has the advantage that the resulting bismuth titanate niobate-based relaxor ferroelectric energy storage ceramic material effectively overcomes the low energy storage density and efficiency of conventional ferroelectric materials, especially bismuth layered ferroelectric materials, making the energy storage performance of the present invention significantly superior to that of undoped bismuth titanate niobate ferroelectric ceramics and other bismuth layered ferroelectric ceramic materials, while also having better working environment stability. The preparation method of the present invention is simple, the raw materials are readily available, and the production efficiency is high, making it suitable for large-scale practical production applications.

The invention discloses a bismuth titanate biomass charcoal composite material for environmental remediation and a preparation method thereof, and relates to the field of environmental functional materials.The composite material takes corncob biomass charcoal as a carrier, and bismuth titanate nanoparticles are loaded on the surface and in pores of the corncob biomass charcoal; the corncob biomass charcoal has a hierarchical porous structure, the specific surface area of the corncob biomass charcoal is not less than 1500 m / g, and the surface of the corncob biomass charcoal is rich in oxygen-containing functional groups; the bismuth titanate nanoparticles and the corncob biomass charcoal are tightly combined through a heterojunction interface; according to the bismuth titanate biomass charcoal composite material for environmental restoration and the preparation method of the bismuth titanate biomass charcoal composite material, firstly, pollutants are rapidly adsorbed and enriched to the periphery of bismuth titanate active sites through the high specific surface area and abundant pore structure of the corncob charcoal, local high concentration is formed, and favorable conditions are created for subsequent photocatalytic reaction; bismuth titanate generates strong oxidizing active oxygen species under excitation of visible light, and adsorbed pollutants are thoroughly degraded.

The application discloses a preparation method of a sheet-shaped Nb element doped modified bismuth titanate catalyst material. 3‑x Nb x O 12 , wherein 0.15<=x<=0.40, the molar ratio of Bi, Ti and Nb is taken as bismuth oxide, titanium dioxide and niobium pentoxide; step two: the raw materials in step one and the mass ratio of the molten salt are mixed, then the mixture is put into a crucible and fully grinded to obtain a mixture; step three: the mixture prepared in step two is fired in a muffle furnace, and a light yellow product is obtained after cooling; step four: the light yellow product prepared in step three is washed with deionized water, filtered and dried to obtain a sheet-shaped Nb element doped bismuth titanate catalyst powder. The technology can significantly improve the structural uniformity, defect concentration and piezoelectric response activity of the material, greatly reduce the energy consumption and time cost, provides an efficient path for large-scale production of high-performance catalysts, and has a wide market prospect.

The application relates to the technical field of nanometer materials, and particularly discloses a bismuth titanate nanometer material, a preparation method thereof and a sewage treatment method. The preparation method of the bismuth titanate nanometer material comprises the following steps: uniformly mixing bismuth oxide, titanium oxide, holmium oxide, sodium chloride and potassium chloride according to a molar ratio of Bi:Ti:Ho:NaCl:KCl=(3.5-3.92):(2.8-3.2):(0.1-0.5):(40-55):(40-55) to obtain a precursor; calcining the precursor to obtain an intermediate product; and removing sodium chloride and potassium chloride in the intermediate product. By implementing the application, the polarity and piezoelectric response of the bismuth titanate nanometer material can be improved, and the piezoelectric-optical catalytic performance of the bismuth titanate nanometer material can be improved.

The invention discloses a bismuth titanate and bismuth vanadate compounded high-performance photoelectrode and a preparation method thereof, and belongs to the technical field of electrode materials. The bismuth titanate composite bismuth vanadate high-performance photoelectrode comprises the BiVO4 layer, the BiVO4-x layer, the Bi4Ti3O12 layer and the NiCoBi layer, the bismuth titanate layer serves as a hole transport layer, the surface state is passivated, transport of carriers is promoted, recombination of surface charges is reduced, and the performance of the electrode is greatly improved; the NiCoBi layer improves the photo-corrosion defect of the material, the catalytic ability of water decomposition is improved, and the stability is obviously improved; and meanwhile, a heterojunction is formed between the BiVO4 layer and the Bi4Ti3O12 layer, so that the separation efficiency of photon-generated carriers is enhanced, and the high-performance photoelectrode with high stability, high carrier separation efficiency and high surface catalytic oxygen production efficiency is finally obtained.

This invention belongs to the field of biomedical materials technology, and relates to a piezoelectrically enhanced nanoenzyme composite material, its preparation method, and its antibacterial application. Cobalt-doped molybdenum disulfide is grown in situ on the surface of bismuth titanate nanosheets to obtain a BTO@Co-MoS2 composite material. This composite material exhibits a piezoelectric effect under pressure stimulation. Electrons, under the influence of the built-in electric field at the BTO@Co-MoS2 interface, promote the self-cycling of the molybdenum disulfide redox pair, thereby improving the catalytic activity of halogen-like peroxidases. Simultaneously, the piezoelectric catalysis of hydrogen peroxide generation alleviates the problem of insufficient endogenous hydrogen peroxide. In antibacterial applications, the piezoelectrically enhanced nanoenzyme composite material prepared by this invention achieves bactericidal rates of 98.39% and 99.95% against Staphylococcus aureus and Escherichia coli, respectively.

This invention relates to the field of piezoelectric ceramics technology, and in particular to a composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic and its preparation method. The general formula for high-temperature piezoelectric ceramics is: Ca 1‑x (LiCe) x / 2 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 , where x is a complex high-valence ion (LiCe). 4+ Twice the molar amount, x = 0.02, 0.05, 0.08, 0.10. This invention employs the above-mentioned composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic and its preparation method to meet the application requirements in high-temperature environments while ensuring the material's environmental friendliness.

The application relates to the technical field of catalysts, and particularly discloses a sulfur-tolerant shift catalyst as well as a preparation method and application thereof. The sulfur-tolerant shift catalyst provided by the application comprises the following components in parts by weight: a carrier, an active component and an additive; the carrier is an acid-modified attapulgite-bismuth titanate composite carrier; the active component is CoO and MoO3, and the loadings of the active component in the catalyst are 2-5 wt% and 8-12 wt% respectively; wherein, the preparation method of the acid-modified attapulgite-bismuth titanate composite carrier comprises the following steps: preparing an acid-modified attapulgite, preparing a bismuth titanate precursor solution, compounding and calcining and activating. The sulfur-tolerant shift catalyst provided by the application has the advantages of low preparation cost, high catalytic activity, good stability and the like, and has a good application prospect.

The invention belongs to the technical field of piezoelectric ceramics, and particularly relates to a high-temperature magnesium bismuth titanate-lead zirconate titanate piezoelectric ceramic material and a preparation method thereof. Comprising the following chemical general formula: 0.65 Bi (Mg < 0.51 > Ti < 0.49 >) O < 3 >-0.35 Pb (Zr < x > Ti < 1-x >) O < 3-y > wt% La2O3, wherein x is equal to 0.01 to 0.7, and y is equal to 0.01 to 2. The piezoelectric ceramic material is prepared from the following raw materials: Pb3O4, TiO2, ZrO2, Nb2O5, Bi2O3, MgO and La2O3. The novel piezoelectric ceramic system has higher Curie temperature of 460-520 DEG C, and can work in a high-temperature environment of 260-400 DEG C. The novel piezoelectric ceramic system is suitable for being applied to a high-temperature sensor piezoelectric device.

The invention provides high-reflection ultralow-temperature UV curing ink, a preparation method thereof and a photovoltaic module, and relates to the technical field of UV curing ink. The high-reflection ultralow-temperature UV curing ink is prepared from the following raw materials in percentage by mass: 50-70% of modified ink oil and 30-50% of glaze powder, wherein the total mass of the raw materials is 100%; the modified ink is prepared from the following raw materials: transparent resin, a high-reflection additive and an auxiliary agent; the glaze powder is prepared from the following raw materials: glass powder, titanium dioxide, bismuth titanate and Bi2Ti2O7 nanocrystals. The high-reflection ultralow-temperature UV curing ink has the advantages that the service life is prolonged, the good environmental protection performance is realized, and the environmental pollution in the production process is favorably reduced; through specific material combination, spectral selectivity is increased, and high reflection of light in a specific wavelength range can be realized, so that the optical performance of the photovoltaic module is optimized; and photo-thermal loss is reduced.

The invention belongs to the technical field of powder preparation by a wet chemical method, and provides a sodium bismuth titanate powder material and a preparation method thereof, the powder material is rhombohedral phase (Bi0. 5Na0. 5) TiO3, the particle morphology of the powder material is a nanocube, and the average size is 76nm. The (Bi0. 5Na0. 5) TiO3 nanocube is prepared through a two-step heating hydrothermal method, has the advantages of being simple in process, low in cost, good in stability and repeatability, capable of being produced on a large scale and the like, and has wide application prospects in the fields of sodium bismuth titanate, sodium bismuth titanate-based ferroelectric ceramics, barium titanate-based thermal sensitive ceramics and the like. The (Bi0. 5Na0. 5) TiO3 nanocube powder prepared by the invention is used as a raw material, (Bi0. 5Na0. 5) TiO3 ceramic sintered at 1100 DEG C for 4 hours has good sinterability and ferroelectricity, the relative density of the (Bi0. 5Na0. 5) TiO3 ceramic is 95% or above, and the maximum polarization intensity, the remanent polarization intensity and the coercive field of the (Bi0. 5Na0. 5) TiO3 ceramic are 40.02 mu C / cm < 2 >, 27.78 mu C / cm < 2 > and 87.5 kV / cm respectively.

The invention provides a piezoelectric catalyst and a preparation method and application thereof. The piezoelectric catalyst comprises a polymerized carbon nitride / bismuth titanate heterojunction. The piezoelectric catalyst is a bifunctional catalyst with high catalytic efficiency and high recycling rate, has the characteristics of simplicity in operation, low cost and environmental protection when being applied to degradation of organic pollutants, and has wide application prospects in the fields of wastewater pollutant degradation, environmental restoration and the like.

This invention discloses a yarn-like ball-shaped BaTiO3 / Bi4Ti3O 12 The preparation method of the catalyst material and the product obtained are described. An ethanol solution of flake-shaped bismuth titanate and tetrabutyl titanate, along with a barium salt solution, are stirred and mixed with an alkaline conditioning solution to obtain an alkaline suspension. After hydrothermal reaction, the suspension is acid-washed, washed, filtered, and dried to obtain yarn-like spherical BaTiO3 / Bi4Ti3O3. 12 Catalyst powder. The catalyst of this invention has a structure of hollow, woolen spheres assembled from nanowires, with nanoparticles embedded on the surface of the spheres. This effectively increases the contact area between the catalyst and the reactants, thereby improving the carrier separation efficiency in piezoelectric catalysis and greatly enhancing catalytic activity. The raw materials of this invention are inexpensive and the operation is simple, solving the problems of complex processes and high costs associated with the synthesis of one-dimensional catalysts or the need for templates and morphology modifications in existing technologies. The product can be applied in photocatalysis and piezoelectric catalysis, and has high application value.

The invention relates to a calcium bismuth titanate piezoelectric ceramic with a high piezoelectric constant and a piezoelectric voltage constant and a preparation method of the calcium bismuth titanate piezoelectric ceramic. The chemical composition of the bismuth calcium titanate piezoelectric ceramic is Ca < 0.94 > Bi < 4.06 > Ti < 4 > O < 15-x > wt% MgO, x represents the mass percent of MgO in a Ca < 0.94 > Bi < 4.06 > Ti < 4 > O < 15 > matrix, and x is greater than 0 and less than or equal to 0.3. The Ca0. 94Bi4. 06Ti4O15 component with good piezoelectric property is taken as a matrix, and MgO with low dielectric constant is added, so that the dielectric constant of the calcium bismuth titanate-based high-temperature piezoelectric ceramic is regulated and controlled; meanwhile, a built-in electric field can be established when the free moving charges are polarized, so that the polarization intensity is enhanced, and the piezoelectric property is improved.

The invention relates to a calcium bismuth titanate piezoelectric ceramic with high piezoelectric property and high-temperature resistivity and a preparation method thereof. The chemical composition of the bismuth calcium titanate piezoelectric ceramic is Ca < 1-x > Bi < 4 + x > Ti < 4 > O < 15 >, and x is the mole percent, 0 lt; x is less than or equal to 0.08. By designing the composition of the calcium bismuth titanate, replacing Ca < 2 + > with Bi < 3 + > and utilizing space charge polarization to improve the piezoelectric property, the piezoelectric property and the high-temperature resistivity of the calcium bismuth titanate piezoelectric ceramic are remarkably improved under the condition that the high Curie temperature of the calcium bismuth titanate piezoelectric ceramic is maintained, and the calcium bismuth titanate piezoelectric ceramic with high Curie temperature, high piezoelectric property and high direct-current resistivity is obtained. The requirements of the piezoelectric ceramic material for the high-temperature piezoelectric vibration sensor are met, and the application of the piezoelectric ceramic material in the high-temperature field is promoted.

The invention relates to the technical field of piezoelectric ceramics, in particular to composite ion modified bismuth layered calcium bismuth titanate-based high-temperature piezoelectric ceramics and a preparation method thereof, the general formula of the high-temperature piezoelectric ceramics is Ca < 1-x > (LiCe) x / 2 Bi < 3.75 > Nd < 0.25 > Ti < 3.935 > Sc < 0.065 > O15, x is two times of the molar weight of composite high valence ions (LiCe) < 4 + >, and x = 0.02, 0.05, 0.08 and 0.10. According to the composite ion modified bismuth layered calcium bismuth titanate-based high-temperature piezoelectric ceramic and the preparation method thereof disclosed by the invention, the application requirements in a high-temperature environment are met, and meanwhile, the environment friendliness of the material is ensured.

The invention discloses an ultrasonic and visible light dual-energy driven bismuth titanate-polydopamine-silver iodate composite catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: S1, preparing a BTO nanosheet; s2, modifying the BTO nanosheet by using polydopamine; and S3, compounding the AIO with the BTO modified by the polydopamine. Nanosheet-layer bismuth titanate is used as an inner core, polydopamine is grafted for surface modification, then composite silver iodate nanosheets are deposited on the outer layer, the composite catalyst of a two-dimensional / two-dimensional composite structure in which BTO and AIO make full contact is formed, the composite catalyst has an inner core piezoelectric electric field, an S-type heterojunction and other built-in electric fields, and the BTO / AIO composite catalyst has the advantages that the BTO / AIO composite structure is obtained; the separation path of ultrasonic and visible light-generated carriers is shortened through multiple channels, the separation speed of the carriers is increased, the composite catalyst can be successfully used as an efficient composite catalyst for synthesizing H2O2, and a proton donor is not needed. The composite catalyst is simple in preparation process, low in cost, stable in catalytic performance and beneficial to popularization and application.

The invention provides Sb < 3 + > / Ta < 5 + > co-doped bismuth titanate-based piezoelectric ceramic. The chemical formula of the piezoelectric ceramic is Bi4Ti < 3-2x > (SbTa) xO12, wherein x is not less than 0.01 and not more than 0.03. According to the Sb < 3 + > / Ta < 5 + > co-doping regulation and control method provided by the invention, by increasing lattice distortion and reducing oxygen vacancy concentration, the electrical property of the material is improved while the relative stability and high density of the material structure are ensured. The result shows that the Sb < 3 + > / Ta < 5 + > co-doping not only can obviously improve the piezoelectric coefficient of the BIT ceramic to 25.1 pC / N, but also can ensure that the BIT ceramic still has excellent resistivity of 8.1 * 10 < 6 > omega.cm at 500 DEG C. The invention also provides a preparation method and application of the Sb < 3 + > / Ta < 5 + > co-doped bismuth titanate-based piezoelectric ceramic.

This invention provides a method for preparing bismuth titanate nanoparticles using molten salt assistance. Sodium bismuthate dihydrate, sodium sulfite, titanium sulfate, and sodium nitrate are mixed and ground uniformly to obtain a solid mixture. The solid mixture is then heated at 350°C to melt the sodium nitrate, creating an ion-molten liquid environment. Under this environment, a redox reaction between sodium bismuthate dihydrate and sodium sulfite generates the transition product bismuth oxysulfate, producing sodium hydroxide and creating a self-generated alkaline condition. Simultaneously, under this self-generated alkaline condition, bismuth oxysulfate reacts with titanium sulfate to form bismuth titanate. The reaction product is then post-processed to obtain Bi... 24 Ti2O 40 Nanoparticles. The advantages of this invention are: a synthesis strategy based on an ion-molten liquid environment, accelerated reactant diffusion, and improved chemical reaction efficiency to prepare Bi. 24 Ti2O 40 Nanopowders are easy to prepare, convenient to operate, have a mild reaction, and are low in cost, making them suitable for industrial production.

The invention relates to the technical field of ferroelectric ceramic manufacturing, in particular to a calcium bismuth titanate based ferroelectric ceramic material and a preparation method and application thereof. The chemical formula of the calcium bismuth titanate-based ferroelectric ceramic material is CaBi4-xRxTi4O15-yMnO2, R is one or more of lanthanide rare earth elements, in the formula, x is more than 0 and less than or equal to 0.2, and y is more than or equal to 0.1 wt% and less than or equal to 0.5 wt%. The calcium bismuth titanate-based ferroelectric ceramic material disclosed by the invention has the original ferroelectric, piezoelectric and dielectric properties, also has a photoluminescence characteristic, and belongs to a novel multifunctional material. The ceramic material has excellent photoelectric properties, and has wide application prospects in the fields of photoelectric integration, micro electro mechanical system, photoelectric sensing, LED technology and the like.

The invention relates to bismuth titanate-based lead-free antiferroelectric ceramic as well as a preparation method and application thereof. The chemical composition of the bismuth titanate-based lead-free antiferroelectric ceramic is Bi (4-x) PrxTi3O12, wherein x is greater than or equal to 1.2 and less than or equal to 1.4. The bismuth titanate-based lead-free antiferroelectric ceramic is successfully designed based on typical three-layer bismuth titanate ceramic by introducing a specific amount of Pr element to induce oxygen octahedron rotation, and has the characteristics of antiferroelectric characteristic, high breakdown field strength, high energy storage density and high efficiency. The bismuth titanate-based lead-free antiferroelectric ceramic has relatively high energy storage application potential, the recoverable energy density is 8.0 to 11.97 J / cm < 3 >, the energy storage efficiency is 75.0 to 87.0 percent, and the breakdown electric field is 898 to 1058 kV / cm.

The invention provides a photo-thermal catalyst as well as a preparation method and application thereof. The photo-thermal catalyst comprises a substrate and an active component, the substrate has a stacked mixed metal oxide structure, and the active component comprises metal nanoparticles; and the metal nanoparticles are precipitated in situ from the matrix and are dispersed on the surface and / or inside the matrix. The photo-thermal catalyst provided by the invention has good catalytic conversion activity on carbon dioxide under the illumination of a full-spectrum xenon lamp, and compared with a bismuth titanate catalyst, the photo-thermal catalyst provided by the invention has better performance of photo-thermally catalyzing reduction of carbon dioxide to produce formic acid. The photo-thermal catalyst provided by the invention has obviously enhanced photo-thermal catalytic efficiency in the carbon dioxide reduction process, and can be used for realizing carbon cyclic utilization and relieving the greenhouse effect.

The invention discloses a crystal face junction bismuth titanate photocatalyst, which is a Bi4Ti3O12 material with a macroporous-mesoporous graded porous framework and has a continuous (001) / (100) crystal face junction. The preparation method comprises the following steps: 1) adopting plant stem tissues as a biological template precursor, and performing alkaline leaching, acid leaching and other treatments to obtain a biological template; 2) dissolving a bismuth source and a titanium source in an organic solvent / strong acid mixed solution; then, a biological template is soaked in the obtained Bi4Ti3O12 precursor solution; and 3) carrying out segmented high-temperature calcination on the product obtained in the step 2) in an air atmosphere to prepare the crystal face junction Bi4Ti3O12 photocatalyst. A biological template method is combined with a segmented high-temperature calcination process to induce synchronous construction of a hierarchical porous structure and a crystal face junction, efficient and directional separation of space charges is achieved, and the H2O2 synthesis efficiency and the organic pollutant degradation and mineralization capacity under the low-light-intensity condition are remarkably improved.

The invention provides a piezoelectric catalyst and a preparation method and application thereof. The piezoelectric catalyst is amorphous zinc-cadmium-sulfur composite bismuth titanate and comprises a bismuth titanate nanosheet and amorphous zinc-cadmium-sulfur nanoparticles attached to the bismuth titanate nanosheet. The piezoelectric catalyst provided by the invention has very high degradation efficiency on organic pollutants, and still keeps very high catalytic activity after being repeatedly recycled.

The invention discloses a preparation method and application of a composite photocatalyst guided by a ferroelectric polarization field. The preparation method comprises the following steps: synthesizing a layered ferroelectric material bismuth titanate nanosheet from a catalyst raw material through a molten salt method; the bismuth titanate nanosheet is subjected to surface etching treatment, a catalyst BT-HCL is obtained, nano Ag particles are loaded on the catalyst BT-HCL through a photodeposition method, and the silver-loaded catalyst is obtained. According to the invention, selective anchoring and uniform dispersion of Ag nanoparticles on the surface of the catalyst and in pores are realized by using a ferroelectric polarization field, agglomeration is avoided, spatial selective distribution of the Ag nanoparticles is realized, in gas-solid phase CO2 photocatalytic reduction, the CO yield can reach more than 16 times that of original Bi4Ti3O12, the selectivity is high, the stability is good, and the photocatalytic CO2 reduction performance of the Bi4Ti3O12 is improved.