42 results about "Truncated octahedron" patented technology

An alloy catalyst for redox reaction which is capable of obtaining even superior catalytic activity comprises alloy particles of platinum and nickel, wherein the alloy particle is equipped at an outer surface with a crystal lattice plane represented by a Miller index {111}, and has an average particle diameter in a range of from 6 to 20 nm. The alloy particle preferably takes a shape selected from a regular octahedron, a truncated octahedron, a regular tetrahedron, and a truncated tetrahedron.

A preparation method of vanadate photocatalytic material. The invention relates to a preparation method of a photocatalytic material. The present invention aims to solve the problem that introduction of high valent and difficultly removed organic additives in the existing bismuth vanadate BiVO4 preparation process leads to poor purity of BiVO4. The method comprises the following steps: adding bismuth nitrate and ammonium metavanadate into the nitric acid, heating to dissolve, and adjusting the pH value to 1-6.5 to obtain a mixed solution; transferring the mixed solution to a reaction kettle, placing the reaction kettle into an oven with a temperature of 120-180 DEG C for heat treatment for 6-12 h, washing and drying to obtain the vanadate photocatalyst material. The photocatalytic material is vanadate BiVO4 with a hollow grading structure, has a construction unit of an octahedron or a truncated octahedron and a purity of not less than 99%, and can be used for degradation of organic pollutants.

The invention belongs to the technical field of preparation of supported nano crystal catalysts and in particular relates to in situ controllable equipment for hydrotalcite-supported Pd nano crystal catalysts with different morphologies and research on activity of the hydrotalcite-supported Pd nano crystal catalysts in catalysis of a Heck coupled reaction. The synthesis process of the hydrotalcite-supported Pd nano crystal catalyst comprises the following step of: growing Pd nano crystals with different morphologies (cube, truncated octahedron and triangle) and different exposed crystal faces ({111} and {100}) in situ on the surface of hydrotalcite by adopting a one-pot synthesis method under the conditions of different reducing agents (polyvinylpyrrolidone and ethylene glycol) and surface capping agents (I<->, Cl<-> and polyvinylpyrrolidone) with a mixed solution composed of Na2PdCl4 and nitrate intercalation hydrotalcite. Besides, the synthesized hydrotalcite-supported Pd nano crystal catalysts with different morphologies are used for evaluating the Heck coupled reaction and researching a catalytic activity sequence of different exposed Pd crystal faces of the hydrotalcite-supported Pd nano crystal catalysts, and a foundation is laid for further reasonably designing an efficient supported nano crystal catalyst.

The invention discloses a preparation method of graphene quantum dots-sensitized urchin-like titanium dioxide photocatalytic material; the preparation method comprises: preparing nano TiO2 powder, preparing GQDs (graphene quantum dots) via thermal cracking, preparing GQDs-TiO2 and other steps. The GQDs-sensitized urchin-like TiO2 provided herein is different from conventional anatase TiO2, and is TiO2 having special spherical urchin morphology; compared with truncated octahedral morphology of the original anatase TiO2, the TiO2 has greatly improved active surface area; spatial size of urchin spikes is of submicron level, capillary effect can be generated, bonding of liquid pollutants to the catalytic surface of the TiO2 is promoted, and photocatalytic effect of the TiO2 is improved. The preparation method is low in cost, handy, and easy to use to achieve large-scale production.

The invention discloses an alpha-Fe2O3 nanorod and an Au / alpha-Fe2O3 catalyst, and synthesis and application thereof. The alpha-Fe2O3 maintains a porous nanorod-shaped structure, and the average size of an Au particle is increased to 8.6nm from 2.2nm. Meanwhile, the alpha-Fe2O3 nanorod-shaped structure can also modulate a morphology of an Au nanometer particle, and the morphologies of the Au nanometer particles on the Au / alpha-Fe2O3 catalyst roasted at the temperature of 300, 400 and 500 DEG C respectively are respectively a two-dimensional thin stratified structure, three-dimensional truncated octahedron and a schistose truncated octahedron, so that the peculiarity of the alpha-Fe2O3 rod-shaped structure on dispersing and stabilizing the Au nanometer particles is embodied. The prepared Au / alpha-Fe2O3 catalyst can catalyze CO oxidation at room temperature, and the reaction rate reaches to 0.8047mol CO / gAuh.

The invention discloses a graduated porous titanium dioxide microsphere, and a preparation method and applications thereof. According to the preparation method, preparation is completed via one-step hydrothermal reaction; the preparation method is simple and convenient; yield is high; large-scale production can be realized easily; the graduated porous titanium dioxide microsphere possesses a microspheric structure; microsphere diameter ranges from 2 to 5<mu>m; the graduated porous titanium dioxide microsphere is obtained via assembling of truncated-octahedral nanocrystals; the particle size of the truncated-octahedral nanocrystals ranges from 50 to 100nm; anatase phase high-energy (001) crystal faces are exposed; the graduated porous titanium dioxide microsphere possesses a graduated porous structure; pore size ranges from 5 to 20nm. Indirectly-heated gas sensor technology can be adopted for coating, welding, and aging of the graduated porous titanium dioxide microsphere material so as to prepare semi-conductive type gas sensors. It is shown by gas sensitive property testing results that the semi-conductive type gas sensors possesses structural enhanced gas-sensitive property on acetone, and research approach of resistance-type semiconductor gas sensors is widened.

The invention relates to a three-dimensional overall modular expansion structure, and belongs to the technical field of design of expansion structures. The truncated octahedron-shaped overall expansion structure and the quadrangular-shaped overall expansion structure are the basic cellular structures, by which the three-dimensional overall modular expansion structure can be established. The truncated octahedron-shaped overall expansion structure is used as a hinge-typed link in the three-dimensional overall modular expansion structure. The quadrangular-shaped overall expansion structure is meshed with the truncated octahedron-shaped overall expansion structure to expand the overall structure. A dimensional rectangular coordinate system should be established, using the center of the truncated octahedron-shaped overall expansion structure as its base point and the plane center lines drawn between the base point and the center of six truncated planes as its x-axis, y-axis and z-axis. The truncated octahedron-shaped overall expansion structure and the quadrangular-shaped overall expansion structure should be connected in the x-axis, y-axis and z-axis directions. The three-dimensional overall modular expansion structure has the advantages of being modularized and easily operated. The problem of lacking in designing and constructing the three-dimensional overall modular structure can also be solved.

Tensegrity structures and methods of constructing tensegrity structures of three-dimensional tensegrity lattices formed from truncated octahedron elementary cells. Space-tiling translational symmetry is achieved by performing recursive reflection operations on the elementary cells. This topology exhibiting unprecedented static and dynamic mechanical properties.

Demanding chemical reactions typically require a catalyst of three-dimensional form rather than a flat surface. For ethane hydrogenolysis, one example, reaction rates increase by a factor of 20 by inserting into the reactants a 20-angstrom diameter micro-particle of surface nickel over a truncated octahedron base. Advanced nanotechnological processing techniques with ultrahigh cooling rates such as chill block melting will produce a locally atomically flat substrate. Placing this substrate in compressive stress and then depositing a catalytically active metal such as nickel or platinum on the substrate in a conventional atomic layer deposition system will create nano-scale surface ripples. The ripple wavelength and slope in two dimensions can be optimized to mimic the geometry of the bulk catalyst particles. This modified rippled surface built up over the substrate will have the enhanced catalytic properties of the nano-sphere catalyst, but will be firmly attached to the substrate, a marked advantage over insertion of catalytic particles into the reactant flow stream. This new surface will also allow far more efficient catalytic conversion of reactants flowing over the surface than simply a flat metal catalytic surface. For an automobile catalytic converter whose flow stream comprises gases with hydrocarbons requiring demanding catalytic reactions, such a modified surface will allow construction of a converter that is substantially smaller and less expensive than now exists. However, this technique is not confined to this particular application but is a general technique for enhancing the efficiency of demanding catalytic reactions utilizing fixed catalytic surfaces.

The present invention provides oxide particles having a compositional formula of Pb(ZrxTi1-x)O3, wherein x is 0.46≦x≦0.6; wherein a size of the particle is from 0.5 to 10 μm; a porosity of a surface of the particle is 20% or less; and a shape of the particle is any one of a cube, a rectangular parallelepiped, or a truncated octahedron.

The invention discloses a method for preparing anode materials lithium nickel manganese oxide with micron-size truncated octahedral structures. The method includes steps of (1), dissolving lithium salt, nickel salt and manganese salt in absolute ethyl alcohol solution at the room temperature according to a molar ratio of 2.1:1:3 and ultrasonically stirring the lithium salt, the nickel salt, the manganese salt and the absolute ethyl alcohol solution to obtain clear and transparent solution; (2), adding graphite into the solution and continuously ultrasonically stirring the graphite and the solution for 1-6 h; (3), heating and drying obtained solution by distillation at the temperatures of 60-80 DEG C, recycling solvents, preparing black paste and drying the paste at the temperatures of 60-100 DEG C for 6-15 h; (3), carrying out ball-milling treatment on dried paste for 1-5 h and then calcining the paste at the temperatures of 700-900 DEG C for 8-15 h to obtain the lithium nickel manganese oxide with the micron-size truncated octahedral structures. The molar concentration of manganese ions is 0.2-1.2 mol / L. The molar weight of the graphite is 0.04 times the molar weights of the manganese ions.

The invention discloses a synthesis method of a sub-five nanometer truncated octahedron PtCu nanocrystal. The synthesis method comprises the steps of adding PVP and NaI into an organic solvent DMF, and performing stirring in a room temperature; adding a metal platinum salt precursor solution and a copper salt precursor solution into a mixed solution, and performing stirring in the room temperature, wherein the mole ratio of a metal platinum salt precursor to a copper salt precursor is (1:1)-(1:5); adding hydroxylamine chloride into the obtained mixed solution, and performing stirring in the room temperature, wherein the mass ratio of the hydroxylamine chloride to the PVP is (1:1)-(3:1); transferring the obtained mixed solution to a high-pressure reaction kettle for reaction for 2-12 hours, wherein the temperature is controlled to be 100-150 DEG C; and washing the obtained product after cooling, and performing centrifugal separation to obtain the sub-five nanometer truncated octahedron PtCu nanocrystal. The sub-five nanometer truncated octahedron PtCu nanoalloy has excellent catalytic performance on ethanol oxidation and oxygen reduction in an alkaline medium, and can substitute a current commercial carbon-supported platinum black catalyst.

The invention provides a preparation method of a spinel type single-crystal cobalt-free high-voltage lithium nickel manganese oxide positive electrode material. The method comprises the following steps of A) under the action of a precipitator, ammonia water and a complexing agent, adding a nickel source and a manganese source, and carrying out coprecipitation reaction to obtain a Ni0. 5Mn1. 5(OH)4 binary precursor; and B) mixing the Ni0. 5Mn1. 5(OH)4 binary precursor with a lithium source, carrying out high-temperature calcination, then carrying out low-speed annealing and heat preservation, and finally, naturally cooling to obtain the single-crystal LiNi0. 5Mn1. 5O4 positive electrode material. The main morphology of the material is a combination of a regular octahedron and a truncated octahedron, so that the material has the advantages of low price, simple preparation process, high compaction density, excellent electrochemical performance and the like. The invention also provides the spinel type single-crystal cobalt-free high-voltage lithium nickel manganese oxide positive electrode material and a lithium ion battery.

An improved dimple pattern for a golf ball is disclosed. The dimples may be arranged according to an Archimedean pattern. The dimples may be arranged on the golf ball such that there is no great circle about the golf ball that does not intersect a dimple. Preferred Archimedean patterns include a truncated octahedron, a great rhombcuboctahedron, a truncated dodecahedron, and a great rhombicosidodecahedron. A nonplanar parting line may be used. The parting line may include a parallel segment parallel to the true equator of the golf ball and a plurality of diverging segments that diverge and converge relative the true equator. The parallel segment may be non-collinear with the true equator. The diverging and converging parting line segments may cooperate to form areas that diverge and converge away from the true equator. The size of this area may be designed to not fully surround the biggest dimple or to minimize any undercut.

The invention relates to a three-dimensional wireless sensor network coverage method and system. In the system, a target space is filled by taking a truncated octahedron as a filling subunit; arranging a sensor node at each overlapped vertex of any two adjacent truncated octahedrons, and arranging a node at each vertex, except the overlapped vertex, of all truncated octahedrons; taking the sensing radius as a coverage radius, and judging whether the target space is covered by k or not according to the coverage radiuses of all nodes; if the target space is not covered by k, progressively increasing deployment nodes in the truncated octahedron one by one, and after the target space is covered by k, performing dormancy on part of the nodes according to sensing contribution and decision parameters of the nodes; and an improved artificial bee colony awakening algorithm is adopted to perform staged awakening, so that the energy consumption of the nodes can be reduced by performing dormancy and awakening on all the nodes while the target space is ensured to be covered by k, and the service life of the nodes is prolonged.

The invention relates to a method of using a membrane distributor to greenly prepare cuprous oxide with controllable morphology. The method comprises: using a raw material (mixture of copper salts, alkali sources and citrates) of cuprous oxide as a continuous phase and the reducing agent glucose as a disperse phase, passing the disperse phase through membrane holes at a certain rate into the continuous phase, allowing reacting to form cuprous oxide particles of specific morphology, filtering, washing, and drying to obtain cuprous oxide powder. The method has the advantages that cuprous oxide particles having different morphologies, such as sphere, cuboid, truncated octahedron, octahedron and octangle, and different particle sizes can be prepared just by adjusting reaction material concentration; the reaction solution is quickly and efficiently mixed in micro drop form via a membrane dispersion technique, mass transfer is enhanced, the product has uniform and regular particle size and morphology; using high-price surfactants and toxic reducing agents or organic solvents is not required; the method features good operational convenience, greenness, safety, good amplifying convenienceand the like.

The invention discloses a porous artificial temporal-mandibular joint structure and a making method.The porous artificial temporal-mandibular joint structure comprises a coracoid, a condyle process, a condyle process neck and titanium plates provided with nail holes.The coracoid protrudes from the front edge of the upper end of the condyle process neck, the condyle process protrudes from the back edge of the upper end of the condyle process neck, and the titanium plates are arranged at the lower end of the condyle process neck.The artificial temporal-mandibular joint is a porous component and is composed of a plurality of mesh units, the mesh units are in hollowed truncated octahedron shapes, the thickness of frames of the mesh units ranges from 200 microns to 300 microns, the apertures of the mesh units range from 500 microns to 1,250 microns, and the porosity of a porous body is 75%-80%.The strength of the porous artificial temporal-mandibular joint structure is similar to that of primary skeleton of a patient, the tenacity of the porous artificial temporal-mandibular joint structure is similar to that of the primary skeleton of the patient, stress concentration generated after implantation can be avoided, and the porous structure can assist peripheral tissues in combination with the artificial temporal-mandibular joint.

The invention discloses a linearly arranged artificial porous bone structure, comprising a shell and a porous body in the shell, wherein the porous body is formed by linear connection and arrangement of multiple grid cells, each grid cell is of a hollow truncated octahedron, the thickness of a frame of each grid cell is 200 to 300mu m, the aperture of each grid cell is 500 to 1250mu m, and the porosity of the porous body is 75 percent to 80 percent. According to the linearly arranged artificial porous bone structure, the porous body prepared by utilizing 3D (three dimensional) selective laser melting integral molding is high in porosity and high in strength, a highly interconnected spatial through-hole structure can provide extensive bone ingrowth, the high friction coefficient can provide good initial stability of a transplant, and a considerable clinical medical prospect is achieved.

The invention discloses a multi-defect multi-doped titanium dioxide nanoparticle with high visible light catalytic activity and a preparation method. The titanium dioxide has a size of 10 to 20 nanometers, a particle diameter of 10 to 20 nanometers, and a specific surface area of ​​140 to 160 cm. 3 , truncated octahedral nanoparticles where {001} and {101} planes coexist. The preparation method is to first use tetrabutyl titanate and ammonium hexafluorotitanate as titanium source and fluorine source respectively, and synthesize TiO by hydrothermal method. 2 and NH 4 TIOF 3 mixture, the prepared sample was further treated with boric acid, NH 4 TIOF 3 It undergoes a topological transformation process and is converted into titanium dioxide while achieving in-situ doping of a small amount of nitrogen to obtain titanium dioxide with exposed {001} crystal planes. Then the photoreduction method is used to introduce a large number of defects on the surface of titanium dioxide and achieve fluorine doping at the same time. The oxygen defects introduced in the present invention can significantly improve the absorption of visible light by titanium dioxide. At the same time, the exposure of {001} crystal planes and the co-doping of nitrogen and fluorine atoms improve the separation of carriers during the photocatalytic process. This enables it to efficiently degrade rhodamine B under visible light irradiation.

The invention discloses a preparation method of jarosite. The jarosite is prepared by carrying out hydrothermal reaction on potassium permanganate and hexahydrated ammonium ferrous sulfate. Specifically, the preparation method of the jarosite comprises the following steps of: dissolving the hexahydrated ammonium ferrous sulfate and potassium permanganate in water in a weight ratio of 15:2 to 20:1; placing the solution to a sealed hydrothermal reaction kettle for being heated the solution to 100 DEG C to 200 DEG C to carry out hydrothermal reaction for 2 hours to 16 hours; and performing post-treatment to obtain jarosite after the reaction is finished. The preparation method of the jarosite disclosed by the invention has the advantages of being simple in process, convenient to operate and suitable for industrial production; moreover, the reaction conditions are gentle without solvent pollution, and so the preparation method belongs to a green synthesis process. According to the preparation method of the jarosite disclosed by the invention, the jarostie with a regular appearance and an octahedral structure or an octahedral section structure can be finally obtained by controlling the reaction temperature, the reaction time and the weight ratio of the hexahydrated ammonium ferrous sulfate to the potassium permanganate.

The invention relates to a preparing method of a monoclinic phase truncated octahedron bismuth vanadate crystal. The method comprises the steps of obtaining a solution A through bismuth nitrate pentahydrate, a nitric acid solution and a fluorinion solution; obtaining a solution B through ammonium metavanadate and a sodium hydroxide solution; obtaining a solution C through the solution A and the solution B; conducting a microwave hydrothermal reaction on the solution C to obtain a crystal sample; cleaning and drying the crystal sample to obtain the monoclinic phase truncated octahedron bismuthvanadate crystal. According to the preparing method, the microwave hydrothermal reaction is adopted for preparing the bismuth vanadate crystal, and by controlling the mole ratio of fluorine ions to bismuth ions, the reaction temperature, the reaction time and other parameters, the bismuth vanadate crystal with a monoclinic phase truncated octahedron is prepared and synthesized; the prepared crystal has the advantages of being high in purity and good in photocatalytic performance.

The invention provides a three-dimensional dense friction nanometer power generation module and system. The module includes a shell provided as a truncated octahedron, a nanosphere arranged in the shell and having the size matched with that of the shell to enable the nanosphere and the shell to generate relative motion, and a friction motor attached to the inner surface of the shell and used for generating a current through mutual friction with the nanosphere. The shell of the friction nanometer power generation module is designed to be in a truncated octahedron shape, so that the number of friction nanometer power generation units capable of being placed in unit space reaches the maximum, and the space utilization rate of the system is greatly increased.

The invention discloses a palladium truncated octahedron nanometer material and a preparation method thereof, belongs to the field of palladium nanometer material preparation methods, and solves the technical problem of simple, green and quick preparation of the palladium truncated octahedron nanometer material. Dry Chinese parasol leaves are selected, and are cleaned for drying and crushing; then, Chinese parasol leaf powder and distilled water are fed in a flask for normal-pressure extraction under a certain temperature to obtain extract liquid; palladium salt water solution with a certain mole concentration and cetyl trimethyl ammonium bromide are prepared; the palladium salt water solution and the cetyl trimethyl ammonium bromide are weighed according to the volume ratio, and are uniformly stirred to obtain mixed palladium salt water solution; and the extract liquid, the mixed palladium salt water solution and the distilled water are weighed according to a certain volume ratio forheating and stirring reaction by a certain time to obtain the palladium truncated octahedron nanometer material after centrifugation, cleaning and drying. The method is simple, green and quick.

The invention belongs to the technical field of chemical synthesis, and discloses a chemically catalytically synthesized iron series pigment ihleite and a preparation method thereof. The method is characterized in that the iron series pigment ihleite is prepared through a reaction of reactants comprising ferrous sulfate and sulfate under acidic conditions with at least one of sodium nitrite and nitric acid as a catalytic oxidant. The iron series pigment ihleite is prepared through a hydrothermal reaction through carrying out catalytic oxidation on ferrous sulfate by the efficient catalyst sodium nitrite or nitric acid, so the use amount of the catalyst is small, and the catalysis efficiency is high; and the method has the advantages of mild reaction conditions, implementation of the reaction under normal pressure or a pressurized condition, simple process, simple operation, suitableness for industrial production, high production efficiency, low cost and environmental protection. The ihleite product with uniform particle size, a bright and pure color, a structured morphology and a basically octahedral structure or truncated octahedral structure is finally obtained through controlling the reaction temperature, the reaction time and the material ratio, the purity is 89% or above, and the iron series pigment ihleite has wide application prospect.

The invention discloses a three-dimensional environment-oriented wireless sensor network coverage enhancement method and system. The method includes: using truncated octahedrons to seamlessly stack the three-dimensional area to be monitored, and determining the centroid coordinate matrix; calculating the distance matrix according to the centroid coordinate matrix and the position matrix of each sensor node at the current iteration number; The algorithm solves the bipartite graph maximum matching model; exchanges the optimal mobile task matrix corresponding to the optimal solution; moves N sensor nodes according to the exchanged results, and determines the position coordinates of the moved N sensor nodes; Calculate the coverage rate of the wireless sensor network according to the position coordinates of the moved N sensor nodes; iterate according to the coverage rate and the current iteration value until the end. The invention can reduce the total mobile energy consumption of each sensor node and balance the remaining energy of each sensor node under the premise of improving the coverage rate of the wireless sensor network in the three-dimensional environment.

The invention relates to the technical field of wireless communication networks, and particularly provides a three-dimensional sensor deployment method and system based on a regular grid. The method comprises the following steps: constructing a plurality of random movement deployment models of a sensor based on a regular grid structure; the random mobile deployment model comprises at least one of a cubic basic sensor network model, a regular hexagonal prism basic sensor network model, a rhombic dodecahedron basic sensor network model and a truncated octahedron basic sensor network model; based on the plurality of random movement deployment models of the sensor, determining connectivity of different random movement deployment models of the sensor under different sensing radiuses and communication radiuses; according to the connectivity of different random movement deployment models of the sensor, the random movement deployment model meeting the preset condition is determined from the multiple random movement deployment models to deploy the sensor, random movement deployment and polyhedral coverage deployment of the sensor in a three-dimensional space are achieved, and high reliability and connectivity are achieved.

The invention discloses a chemical molecule satellite with high deformability. The chemical molecule satellite comprises an atomic satellite and a single mechanical arm and / or double mechanical arms. The atomic satellite is constructed to be in a truncated octahedron shape, the atomic satellite comprises eight first functional areas and six second functional areas, and at least one of the first functional areas and the second functional areas is provided with a connecting structure; the single mechanical arm comprises a rod-shaped arm body, a first connecting part and a second connecting part, the first connecting part and the second connecting part are arranged at the two ends of the arm body, the first connecting part and the second connecting part can at least partially rotate and bend relative to the arm body, and both the first connecting part and the second connecting part can be connected to a connecting structure. The double mechanical arms are formed by connecting two adjacent single mechanical arms. The chemical molecule satellite can be flexibly deformed to form various different configurations, can perform quick response, has higher survival adaptability, and can meet various different task requirements.

The invention discloses a biological molecular dynamics detection method under an ellipsoidal-cavity mirror image model. The method is implemented mainly through the construction of the ellipsoidal-cavity mirror image mixed solvent model; the model comprises an ellipsoid and a truncated octahedron arranged in the ellipsoid; the truncated octahedron is a 14-sided polyhedron formed by 6 quadrangles and 8 hexagons. Compared with an existing spherical-cavity mirror image solvent model, the structure of the ellipsoidal-cavity mirror image mixed solvent model, provided by the invention, is more effective in biological macromolecular dynamics simulation of some slender biological macromolecules such as actin and DNA.

The invention relates to a preparing method of a monoclinic phase truncated octahedron bismuth vanadate crystal. The method comprises the steps of obtaining a solution A through bismuth nitrate pentahydrate, a nitric acid solution and a fluorinion solution; obtaining a solution B through ammonium metavanadate and a sodium hydroxide solution; obtaining a solution C through the solution A and the solution B; conducting a microwave hydrothermal reaction on the solution C to obtain a crystal sample; cleaning and drying the crystal sample to obtain the monoclinic phase truncated octahedron bismuthvanadate crystal. According to the preparing method, the microwave hydrothermal reaction is adopted for preparing the bismuth vanadate crystal, and by controlling the mole ratio of fluorine ions to bismuth ions, the reaction temperature, the reaction time and other parameters, the bismuth vanadate crystal with a monoclinic phase truncated octahedron is prepared and synthesized; the prepared crystal has the advantages of being high in purity and good in photocatalytic performance.