CN112746319A

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Info

Publication number: CN112746319A
Application number: CN201911036080.5A
Authority: CN
Inventors: 谢奎; 林国明
Original assignee: Fujian Institute of Research on the Structure of Matter of CAS
Current assignee: Fujian Institute of Research on the Structure of Matter of CAS
Priority date: 2019-10-29
Filing date: 2019-10-29
Publication date: 2021-05-04

Abstract

Translated fromChinese

本申请公开了一种多孔氮化铌单晶材料及其制备方法和应用，所述多孔氮化铌单晶材料中含有10nm～1000nm的孔，多孔氮化铌单晶材料中可以掺杂有0～5％的其他过渡金属元素。多孔氮化铌单晶作为一种新材料，在多孔催化，电催化领域以及电化学能源存储系统中都有潜在的应用。此外，该晶体材料的制备方法操作简单、重复性好、价格低廉。The present application discloses a porous niobium nitride single crystal material and its preparation method and application. ~5% of other transition metal elements. As a new material, porous niobium nitride single crystals have potential applications in porous catalysis, electrocatalysis, and electrochemical energy storage systems. In addition, the preparation method of the crystal material has simple operation, good repeatability and low price.

Description

Porous niobium nitride single crystal material and preparation method and application thereof

Technical Field

The application relates to a porous niobium nitride single crystal material and a preparation method and application thereof, belonging to the field of inorganic materials.

Background

Niobium nitride has high relative density (8.47), high melting point (2300 ℃), high hardness (Mohs hardness is 8, microhardness is 14.3GPa), superconductivity, is a typical B-1 type compound, has a sodium chloride crystal structure, has the superconductivity critical temperature of 17.3K, has the upper critical magnetic field of 43T, has high critical current density, high thermal stability and chemical stability, resists neutron irradiation, and is an excellent superconducting thin film material. The alloy is prepared by a sputtering method in a mixed gas of argon and nitrogen. The method is used for manufacturing the superconducting quantum instrument device with high stability.

The transition metal nitride has high melting point, high hardness, corrosion resistance, electrical property and magnetic property similar to those of metal, and can be widely applied to cutting tools, wear-resistant parts, high-temperature structural materials, electromagnetic elements and superconducting materials. Due to the relatively high critical temperature, the gamma phase and the delta phase are expected to be applied to the preparation of a superconducting device, and particularly replace the traditional metal materials (Pb and Nb) on a superconducting radio frequency resonator. As a novel nitride material, niobium nitride has wide application prospect.

Metallic porous solid materials have important applications in photocatalytic and electrochemical energy storage. The large porosity can provide a large specific surface area for a high efficiency reaction. The existing methods for preparing the nano porous material, such as a template method (use of templates), a foaming method (blistering), a dealloying method (dealloying), a Kirkendall effect method (Kirkendall effect), a resonance infiltration method (collective osmotic shock), are complex, the maximum crystal size capable of being prepared is only in the micrometer scale, and a method capable of preparing the macro-scale nano porous niobium nitride single crystal is lacked.

Therefore, it is necessary to provide a method for preparing large-size nano-porous niobium nitride single crystal to provide high-quality nano-porous niobium nitride single crystal material for niobium nitride-based electrode.

Disclosure of Invention

According to one aspect of the present application, there is provided a porous niobium nitride single crystal material having a porous structure with a large size.

The porous niobium nitride single crystal material is characterized by containing 10 nm-1000 nm pores.

Optionally, the porous niobium nitride single crystal material contains 10 nm-500 nm pores.

Optionally, the porous niobium nitride single crystal material is a porous niobium nitride single crystal film and/or a porous niobium nitride single crystal.

Optionally, the porous niobium nitride single crystal is a self-supporting nanoporous niobium nitride crystal.

Optionally, the size of one dimension in the largest surface of the porous niobium nitride single crystal is 0.1 cm-20 cm.

Optionally, the size of one dimension in the largest surface of the porous niobium nitride single crystal is 1cm to 5 cm.

Optionally, the size of the porous niobium nitride single crystal is 0.1 cm-20 cm;

the thickness of the porous niobium nitride single crystal film is 10 nm-100 mu m.

Optionally, the size of the porous niobium nitride single crystal is 1 cm-20 cm.

In another aspect of the present application, there is provided a method for preparing a porous niobium nitride single crystal material, comprising at least: carrying out contact reaction on a niobium source and a feed gas containing ammonia gas to obtain the porous niobium nitride single-crystal material;

wherein the niobium source is at least one selected from lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal and niobium oxide single crystal materials.

Optionally, the niobium oxide is at least one selected from niobium monoxide, niobium dioxide, niobium trioxide and niobium pentoxide.

Further optionally, the niobium oxide is niobium pentoxide.

Optionally, the niobium source is doped with a different transition metal element.

Optionally, the transition metal element comprises at least one of titanium, iron, cobalt, nickel, and copper.

Optionally, the mass ratio of the transition metal element to the niobium source is 0-5%.

Optionally, the niobium source is selected from at least one of lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal, or niobium oxide single crystal, and corresponding doped single crystal raw material.

Optionally, the method for preparing the porous niobium nitride single crystal material at least comprises the following steps: and (3) carrying out contact reaction on a niobium source and a raw material gas containing ammonia gas, and nitriding the niobium source by the raw material gas containing ammonia gas to obtain the porous niobium nitride single crystal material.

Optionally, the feed gas comprising ammonia provides a source of nitrogen.

Optionally, the feed gas comprising ammonia does not comprise a niobium source.

Optionally, the reaction temperature is 873K to 1673K;

the pressure of the reaction is 0.1 Torr-1000 Torr;

the reaction time is 1 min-500 h.

Optionally, the temperature of the reaction is 1273K to 1673K.

Optionally, the temperature of the reaction is 1273K to 1473K.

Optionally, the temperature of the reaction is 1173K to 1373K.

Optionally, the temperature of the reaction is 973K to 1273K.

Alternatively, the pressure of the reaction is 0.1Torr to 700 Torr.

Alternatively, the pressure of the reaction is 10Torr to 400 Torr.

Optionally, the reaction time is 30 min-20 h.

Optionally, the reaction time is 30min to 100 h.

Optionally, the upper temperature limit of the reaction is selected from 973K, 1023K, 1073K, 1123K, 1172K, 1173K, 1272K, 1273K, 1373K, 1473K, 1573K, or 1673K; the lower limit is selected from 873K, 973K, 1023K, 1073K, 1123K, 1172K, 1173K, 1272K, 1273K, 1373K, 1473K, or 1573K.

Optionally, the upper time limit of the reaction is selected from 2min, 10min, 20min, 30min, 50min, 1h, 8h, 10h, 20h, 50h, 100h, 120h, 150h, 200h, 300h, 400h, or 500 h; the lower limit is selected from 1min, 2min, 10min, 20min, 30min, 50min, 1h, 8h, 10h, 20h, 50h, 100h, 120h, 150h, 200h, 300h or 400 h.

Optionally, the upper pressure limit of the reaction is selected from 0.2Torr, 0.5Torr, 10Torr, 20Torr, 30Torr, 50Torr, 100Torr, 200Torr, 300Torr, 400Torr, 500Torr, 600Torr, 700Torr, 800Torr, 900Torr or 1000 Torr; the lower limit is selected from 0.1Torr, 0.2Torr, 0.5Torr, 10Torr, 20Torr, 30Torr, 50Torr, 100Torr, 200Torr, 300Torr, 400Torr, 500Torr, 600Torr, 700Torr, 800Torr or 900 Torr.

Optionally, when the porous niobium nitride single crystal material is a porous niobium nitride single crystal thin film, the time range of the contact reaction between the lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal or niobium oxide single crystal material, and the corresponding doped single crystal raw material and the feed gas containing ammonia gas is 1min to 20 h.

Optionally, when the porous niobium nitride single crystal material is a porous niobium nitride single crystal thin film, the lower limit of the time range of the contact reaction between the lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal or niobium oxide single crystal material, and the corresponding doped single crystal raw material and the feed gas containing ammonia gas is selected from 1min, 2min, 10min, 20min, 30min, 1h, 2h, 3h, 4h, 5h, 8h, 10h, 15h or 18 h; the upper limit is selected from 2min, 10min, 20min, 30min, 1h, 2h, 3h, 4h, 5h, 8h, 10h, 15h, 18h or 20 h.

When the prepared porous niobium nitride single crystal material is a porous niobium nitride single crystal, the contact reaction time is required to ensure that lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal or niobium oxide single crystal material and corresponding doped single crystal raw materials are all converted into the porous niobium nitride single crystal material.

Optionally, when the porous niobium nitride single crystal material is a porous niobium nitride single crystal, the time for the contact reaction of the lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal or niobium oxide single crystal material, and the corresponding doped single crystal raw material with the feed gas containing ammonia gas is 10 h-500 h.

The person skilled in the art can determine the appropriate contact reaction time according to the actual needs and the size of the lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal or niobium oxide single crystal and the corresponding doped single crystal material.

Optionally, when the porous niobium nitride single crystal material is a porous niobium nitride single crystal, the upper limit of the time range of the contact reaction between the lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal or niobium oxide single crystal material, and the corresponding doped single crystal raw material and the feed gas containing ammonia gas is selected from 15h, 20h, 50h, 100h, 120h, 150h, 200h, 250h, 300h, 350h, 400h, 450h or 500 h; the lower limit is selected from 10h, 15h, 20h, 50h, 100h, 120h, 150h, 200h, 250h, 300h, 350h, 400h or 450 h.

By adopting the method provided by the application, the crystal size of the obtained porous niobium nitride single crystal is equal to the size of the adopted lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal or niobium oxide single crystal material and the corresponding doped single crystal material. The required porous niobium nitride single crystal can be obtained by selecting lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal or niobium oxide single crystal with proper size and corresponding doped single crystal material according to actual needs by those skilled in the art.

Optionally, the feed gas containing ammonia comprises ammonia and at least one of argon and hydrogen;

wherein, the flow of ammonia is recorded as a, the flow of argon is recorded as b, and the flow of hydrogen is recorded as c, and the flow of hydrogen satisfies the following conditions:

0.05SLM≤a≤1000SLM；

0SLM≤b≤1000SLM；

0SLM≤c≤1000SLM。

wherein, the flow of ammonia is recorded as a, the flow of argon is recorded as b, the flow of hydrogen is recorded as c, satisfies:

0.05SLM≤a≤10SLM；

0SLM≤b≤1SLM；

0SLM≤c≤1SLM。

optionally, the feed gas comprising ammonia consists of a first gas and a second gas;

the first gas is ammonia; the second gas is at least one of argon and hydrogen.

Optionally, the upper flow range limit of the ammonia gas is selected from 0.1SLM, 0.2SLM, 0.3SLM, 0.5SLM, 1SLM, 1.5SLM, 2SLM, 3SLM, 4SLM, 5SLM, 6SLM, 7SLM, 8SLM, 9SLM, 10SLM, 20SLM, 30SLM, 40SLM, 50SLM, 60SLM, 70SLM, 80SLM, 90SLM, or 100 SLM; the lower limit is selected from 0.05SLM, 0.1SLM, 0.2SLM, 0.3SLM, 0.5SLM, 1SLM, 1.5SLM, 2SLM, 3SLM, 4SLM, 5SLM, 6SLM, 7SLM, 8SLM, 9SLM, 10SLM, 20SLM, 30SLM, 40SLM, 50SLM, 60SLM, 70SLM, 80SLM or 90 SLM.

Optionally, the upper flow range limit of argon is selected from 0.01SLM, 0.1SLM, 0.2SLM, 0.3SLM, 0.5SLM, 0.8SLM, 1SLM, 2SLM, 5SLM, 10SLM, 20SLM, 50SLM, 80SLM, or 100 SLM; the lower limit is selected from 0SLM, 0.01SLM, 0.1SLM, 0.2SLM, 0.3SLM, 0.5SLM, 0.8SLM, 1SLM, 2SLM, 5SLM, 10SLM, 20SLM, 50SLM or 80 SLM.

Optionally, the upper flow range limit of hydrogen is selected from 0.01SLM, 0.1SLM, 0.2SLM, 0.5SLM, 0.8SLM, 1SLM, 2SLM, 5SLM, 10SLM, 20SLM, 50SLM, 80SLM, or 100 SLM; the lower limit is selected from 0SLM, 0.01SLM, 0.1SLM, 0.2SLM, 0.5SLM, 0.8SLM, 1SLM, 2SLM, 5SLM, 10SLM, 20SLM, 50SLM or 80 SLM.

Optionally, the method comprises at least: reacting at least one of lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal or niobium oxide single crystal and corresponding doped single crystal raw materials in an ammonia-containing atmosphere, and performing surface nitriding growth on the lithium niobate single crystal, the sodium niobate single crystal, the potassium niobate single crystal or niobium oxide single crystal and the corresponding doped single crystal raw materials to obtain the porous niobium nitride single crystal film.

Optionally, the method comprises at least: reacting at least one of lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal or niobium oxide single crystal and corresponding doped single crystal raw materials in an ammonia-containing atmosphere, and carrying out surface nitriding transformation growth on the lithium niobate single crystal, the sodium niobate single crystal, the potassium niobate single crystal or niobium oxide single crystal and the corresponding doped single crystal raw materials to obtain the porous niobium nitride single crystal.

As an embodiment, the method for preparing the nano-porous niobium nitride single crystal film and the self-supporting nano-porous niobium nitride single crystal comprises the following steps:

step one, adopting a lithium niobate single crystal, a sodium niobate single crystal, a potassium niobate single crystal or a niobium oxide single crystal and a corresponding doped single crystal raw material sheet as a substrate;

placing the lithium niobate single crystal, the sodium niobate single crystal, the potassium niobate single crystal or the niobium oxide single crystal and a corresponding doped single crystal raw material sheet substrate into a vapor phase epitaxial growth reaction chamber, and carrying out substrate surface nitridation growth in a high-temperature ammonia-containing atmosphere to obtain a nano porous niobium nitride single crystal film;

and step three, further carrying out nitridation conversion growth along with the increase of nitridation time, and completely nitridizing and converting the lithium niobate single crystal, the sodium niobate single crystal, the potassium niobate single crystal or the niobium oxide single crystal and the corresponding doped single crystal raw material sheet substrate into a self-supporting nano porous niobium nitride single crystal.

Optionally, the dimensions of the lithium niobate single crystal, the sodium niobate single crystal, the potassium niobate single crystal or the niobium oxide in the step one and the corresponding doped single crystal raw material single crystal wafer substrate are in the ranges: 0.1 cm-30 cm.

Optionally, the temperature range of the high-temperature nitridation transformation growth in the second step is as follows: 873K-1073K.

Optionally, in the ammonia-containing atmosphere in the second step, ammonia gas with a flow rate of a, argon with a flow rate of b and hydrogen gas with a flow rate of c are adopted, wherein a is more than or equal to 0.05SLM and less than or equal to 1000SLM, b is more than or equal to 0SLM and less than or equal to 1000SLM, and c is more than or equal to 0SLM and less than or equal to 1000 SLM.

Optionally, the nitridation time range in the second step is as follows: 1min to 500 h.

Optionally, the pressure range of the nitriding atmosphere in the second step is as follows: 0.1Torr to 700 Torr.

As a specific implementation method, the method for preparing the nano-porous niobium nitride single crystal film and the self-supporting nano-porous niobium nitride single crystal comprises the following steps:

(a1) adopting a potassium niobate single crystal wafer as a substrate;

(b1) placing the potassium niobate single-crystal wafer substrate in a vapor phase epitaxial growth reaction chamber, and carrying out substrate surface nitridation conversion in a high-temperature ammonia-containing atmosphere to grow a nano porous niobium nitride single-crystal film;

(c1) and further carrying out nitridation transformation growth along with the increase of nitridation time, and completely nitridizing and transforming the potassium niobate single-chip substrate to grow the self-supporting nano porous niobium nitride single-crystal.

The scale range of the potassium niobate single-crystal wafer substrate in (a1) is as follows: 1 cm-5 cm.

The temperature range of the high-temperature nitridation transformation growth in the step (b 1): 1073K-1173K.

And (b1) adopting ammonia gas at a flow rate of a, argon gas at a flow rate of b and hydrogen gas at a flow rate of c in the ammonia-containing atmosphere at (b1), wherein a is more than or equal to 0.05SLM and less than or equal to 10SLM, b is more than or equal to 0SLM and less than or equal to 1SLM, and c is more than or equal to 0SLM and less than or equal to 1 SLM.

The nitriding time range in (b 1): 30 min-100 h.

The pressure range of the nitriding atmosphere in (b 1): 10Torr to 400 Torr.

The nano-porous niobium nitride single crystal in the step (c1) is a large-size (100) surface nano-porous niobium nitride single crystal.

(a2) adopting a sodium niobate single crystal wafer as a substrate;

(b2) placing the sodium niobate single-crystal wafer substrate in a vapor phase epitaxial growth reaction chamber, and carrying out substrate surface nitridation conversion in a high-temperature ammonia-containing atmosphere to grow a nano porous niobium nitride single-crystal film;

(c2) and further carrying out nitridation transformation growth along with the increase of nitridation time, and completely nitridizing and transforming the sodium niobate single-chip substrate to grow the self-supporting nano porous niobium nitride single-crystal.

The scale range of the sodium niobate single-crystal wafer substrate in (a2) is as follows: 1 cm-5 cm.

The temperature range of the high-temperature nitridation transformation growth in the step (b 2): 1173K to 1273K.

And (b2) adopting ammonia gas with a flow rate of a, argon gas with a flow rate of b and hydrogen gas with a flow rate of c in the ammonia-containing atmosphere with a flow rate of a, wherein a is more than or equal to 0.05SLM and less than or equal to 10SLM, b is more than or equal to 0SLM and less than or equal to 1SLM, and c is more than or equal to 0SLM and less than or equal to 1 SLM.

The nitriding time range in (b 2): 30 min-20 h.

Pressure range of nitriding atmosphere in (b 2): 10Torr to 400 Torr.

The nano-porous niobium nitride single crystal in (c2) is a large-size nano-porous niobium nitride single crystal.

(a3) adopting a niobium pentoxide single chip as a substrate;

(b3) placing the niobium pentoxide single crystal substrate in a vapor phase epitaxial growth reaction chamber, and carrying out substrate surface nitridation conversion in a high-temperature ammonia-containing atmosphere to grow a nano porous niobium nitride single crystal film;

(c3) and further carrying out nitridation transformation growth along with the increase of the nitridation time, and completely nitridizing and transforming the niobium pentoxide single crystal substrate to grow the self-supporting nano porous niobium nitride single crystal.

The scale range of the niobium pentoxide single-crystal substrate in (a3) is as follows: 1 cm-5 cm.

The temperature range of the high-temperature nitridation transformation growth in the step (b 3): 1073K to 1273K.

And (b3) adopting ammonia gas with a flow rate of a, argon gas with a flow rate of b and hydrogen gas with a flow rate of c in the ammonia-containing atmosphere with a flow rate of a, wherein a is more than or equal to 0.05SLM and less than or equal to 100SLM, b is more than or equal to 0SLM and less than or equal to 10SLM, and c is more than or equal to 0SLM and less than or equal to 10 SLM.

The nitriding time range in (b 3): 30 min-20 h.

Pressure range of nitriding atmosphere in (b 3): 10Torr to 400 Torr.

The nano-porous niobium nitride single crystal in (c3) is a large-size nano-porous niobium nitride single crystal.

The invention develops a large-size and low-cost nano porous niobium nitride monocrystal film and crystal through nitriding and transforming a large-size lithium niobate monocrystal, a sodium niobate monocrystal, a potassium niobate monocrystal, a niobium oxide crystal or a corresponding doped monocrystal into a nano porous niobium nitride monocrystal crystal with the same size.

In still another aspect of the present application, there is provided a use of at least one of the porous niobium nitride single crystal material described in any one of the above and the porous niobium nitride single crystal material prepared by the method described in any one of the above in the field of catalysis.

In still another aspect of the present application, there is provided a porous niobium nitride single crystal material as described in any one of the above, and a porous niobium nitride single crystal material prepared by the method as described in any one of the above, for use in the field of porous catalysis.

Alternatively, the porous catalyst catalyzes the epoxidation of an olefin.

In still another aspect of the present application, there is provided a use of at least one of the porous niobium nitride single crystal material described in any one of the above and the porous niobium nitride single crystal material prepared by the method described in any one of the above in the field of electrocatalysis.

In the present application, SLM is an abbreviation of Standard Litre Per Minute, and indicates a flow rate of 1L/min in a Standard state.

In the present application, the size of the crystal and the size of one of the largest surfaces of the crystal refer to the distance between two points adjacent to each other on the surface with the largest area of one crystal.

The beneficial effects that this application can produce include:

(1) the characteristics that the lithium niobate single crystal, the sodium niobate single crystal, the potassium niobate single crystal or the niobium oxide crystal and the niobium nitride crystal have similar structures are utilized, so that the lithium niobate single crystal, the sodium niobate single crystal, the potassium niobate single crystal or the niobium oxide single crystal substrate and ammonia gas are nitrided and transformed from outside to inside at high temperature to grow the niobium nitride crystal, and other products are completely volatilized;

(2) the method utilizes the characteristic that the niobium content in lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal or niobium oxide crystal with the same volume is less than that in niobium nitride crystal, so that the lithium niobate single crystal, sodium niobate single crystal, potassium niobate single crystal or niobium oxide single crystal substrate and ammonia gas are subjected to nitridation conversion from outside to inside at high temperature to generate nano porous niobium nitride single crystal;

(3) the application reports a nano porous niobium nitride monocrystal film and a large-size nano porous niobium nitride monocrystal for the first time;

(4) the method for preparing the nano porous niobium nitride single crystal has the advantages of simple operation, good repeatability and low price;

(5) the material has a self-supporting structure, and when the material is a blocky single crystal, the material can be used as a new material and has potential application in the field of porous catalysis/electrocatalysis and electrochemical energy storage systems.

Drawings

FIG. 1 showssample 1^#SEM picture of large-size nano porous niobium nitride single crystal;

FIG. 2 shows sample 2^#SEM picture of large-size nano porous niobium nitride single crystal;

FIG. 3 showssample 3^#SEM picture of large-size nano porous niobium nitride single crystal;

FIG. 4 shows sample M1^#XRD diffraction pattern of (1);

FIG. 5 is a drawingshowingSample 1^#XRD diffraction pattern of (1);

FIG. 6 shows sample M1^#Transmission electron microscopy images of;

FIG. 7 showssample 1^#Transmission electron microscopy images of;

FIG. 8 shows a sample M1^#Scanning electron micrographs of sections;

FIG. 9 is a graph showing the electrical characteristics ofsamples 1# to 3 #.

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

The raw materials in the examples of the present application were all purchased commercially, unless otherwise specified.

Wherein the lithium niobate single crystal is according to the literature [ Shigematsu, k.; anzai, y.; morita, s.; yamada, m.; yokoyama, H.A., GROWTH-CONDITIONS OF SUBGRAIN-FREE LINBO3 SINGLE-CRYSTALS BY THE E CZOCCHRAMLSKI METHOD.Jpn.J.appl.Phys.part 1-Regul.Pap.Brief Commun.rev.Pap.1987,26(12),1988-1996 ].

Sodium niobate single crystals and potassium niobate single crystals are according to the literature [ Shevchenko, n.b.; turk, a.v.; zhestkov, v.f.; smotrakov, v.g.; fesenko, E.G., GROWTH AND ELECTROPHYSICAL PROPERTIES OF KNB

O3 AND NANBO3 CRYSTALS. Inorg. Mater.1979,15(11),1580-1582.

Niobium oxide is according to literature [ Toropov, d.k.; degen, m.g.; bolgartserva, V.P., preamble OF SINGLE-CRYSTALS OF NB2O5 BY CHEMICAL-TRANSPORT REACTION S INVOLVING TECL4.Inorg.Mater.1976,12(2),241-243 ].

The analysis method in the examples of the present application is as follows:

and (4) analyzing by using a JEOL JSM 6330F type scanning electron microscope.

The analysis was carried out by transmission electron microscopy using FEI Titan 3G 260-300.

The PPMS-9T type electrical property analysis is utilized.

EXAMPLE 1 sample M1^#Andsample 1^#Preparation of

Will be 1cm in sizePlacing the potassium niobate single crystal substrate on a high-purity alumina boat, then placing the potassium niobate single crystal substrate into an alumina tube reactor, introducing feed gas containing ammonia (the feed gas consists of ammonia and argon, ammonia 0.2SLM and argon 0.2SLM), heating the system to 1123K, keeping the system pressure at 200Torr, reacting for 120 minutes, cooling to room temperature to obtain a porous niobium nitride single crystal film sample growing on the surface of the potassium niobate single crystal wafer substrate, wherein the film thickness is 500nm, and the sample is marked as M1^#。

Placing a potassium niobate single crystal substrate with the size of 1cm on a high-purity alumina boat, then placing the substrate into an alumina tube reactor, introducing feed gas containing ammonia (the feed gas consists of ammonia and hydrogen, 0.2SLM (ammonia 0.2SLM) and 0.1SLM) and heating the system to 1123K, keeping the pressure of the system at 300Torr, reacting for 100 hours, and cooling to room temperature to obtain a porous niobium nitride single crystal sample, which is recorded assample 1^#Sample No. 1^#Has a crystal size of 1 cm.

EXAMPLE 2 sample M2^#And sample 2^#Preparation of

Placing a sodium niobate single crystal substrate with the size of 1cm on a high-purity alumina boat, then placing the substrate into an alumina tube reactor, introducing feed gas containing ammonia (the feed gas consists of ammonia and argon, ammonia 0.2SLM and argon 0.2SLM), heating the system to 1173K, keeping the system pressure at 50Torr, reacting for 120 minutes, cooling to room temperature to obtain a porous niobium nitride single crystal film sample growing on the surface of the substrate of the sodium niobate single crystal wafer, wherein the film thickness is about 500nm, and the sample is marked as M2^#。

Placing a sodium niobate single crystal substrate with the size of 1cm on a high-purity graphite heating body of a high-frequency induction furnace, then placing the substrate into a quartz reactor, introducing a feed gas containing ammonia (the feed gas consists of ammonia and hydrogen, 0.3SLM (ammonia and hydrogen, 0.2 SLM)) and heating a system to 1173K, keeping the pressure of the system at 200Torr, reacting for 100 hours, and cooling to room temperature to obtain a porous niobium nitride single crystal sample, which is marked as a sample 2^#Sample No. 2^#Has a crystal size of 1 cm.

EXAMPLE 3 sample M3^#Andsample 3^#Preparation of

Placing a lithium niobate single crystal substrate with the size of 1cm on a high-purity alumina boat, then placing the substrate into an alumina tube reactor, introducing feed gas containing ammonia (the feed gas consists of ammonia and hydrogen, ammonia 0.3SLM and hydrogen 0.1SLM), heating the system to 1173K, keeping the system pressure at 50Torr, reacting for 120 minutes, cooling to room temperature to obtain a porous niobium nitride single crystal film sample growing on the surface of the substrate of the lithium niobate single crystal wafer, wherein the film thickness is 1000nm, and the sample is marked as M3^#。

Placing a lithium niobate single crystal substrate with the size of 1cm on a high-purity alumina boat, then placing the substrate into an alumina tube reactor, introducing a feed gas containing ammonia (the feed gas consists of ammonia and hydrogen, 0.3SLM (ammonia 0.1SLM) and heating the system to 1173K, keeping the system pressure at 50Torr, reacting for 120 hours, and cooling to room temperature to obtain a porous niobium nitride single crystal sample, which is marked as asample 3^#Sample No. 3^#Has a crystal size of 1 cm.

EXAMPLE 4 sample M4^#Sample M9^#Preparation of

Sample M4^#Sample M9^#The basic preparation procedure of (1) is the same as that of sample M1 in example 1^#And changing the substrate and the reaction conditions to obtain different samples. The relationship between the sample number and the substrate and the reaction conditions is shown in Table 1.

TABLE 1

Wherein the sample M4^#Sample M9^#The thickness of (a) is within a range of 10nm to 100 μm.

Example 5sample 4^#Sample 9^#Preparation of

Sample No. 4^#Sample 9^#The basic preparation procedure of (1) is the same as that ofsample 1 in example 1^#Change ofSubstrate and reaction conditions, resulting in different samples. The relationship between the sample number and the substrate and the reaction conditions is shown in Table 2.

TABLE 2

Sample numbering	Substrate, raw material gas, reaction temperature and reactionpressure	Reaction time
				4^#	Same as M4^#	120h
5^#	Same as M5^#	120h
			6^#	Same as M6^#	120h
7^#	Same as M7^#	120h
			8^#	Same as M8^#	120h
9^#	Same as M9^#	120h

EXAMPLE 6 sample M10^#And sample 10^#Preparation of

Sample M10^#And sample 10^#The basic production steps of (1) were the same as in example 1, except that the potassium niobate single crystal substrate was doped with 2.5% of Fe element, and the obtained sample was designated as sample M10^#Andsample 10^#。

EXAMPLE 7 sample M11^#Sample 11^#Preparation of

Sample M11^#And sample 11^#The basic preparation procedure of (1) was the same as in example 1, except that the potassium niobate single crystal substrate was doped with 3% of Co element, and the obtained sample was designated as sample M11^#And sample 11^#。

EXAMPLE 8 sample M1^#Sample M11^#Sample 1^#Sample 11^#Characterization of the topography of

The shapes of the sample No. 1to the sample No. 11 are characterized by a scanning electron microscope, and the result shows that the sample No. 1to the sample No. 11 all have holes with the diameters of 10nm to 500 nm. Sample No. 4^#Sample No. 5^#Sample 10^#And sample 11^#Morphology of (1) and sample^#Similarly, assample 1^#As a typical representative, a scanning electron micrograph of the nano-porous niobium nitride single crystal is shown in FIG. 1, and it can be seen that niobium nitride has a porous skeleton structure. Sample No. 6^#Andsample 7^#Morphology of (2) and sample^#Similarly, as sample 2^#As a typical representative, the scanning electron micrograph of the nano-porous niobium nitride single crystal is shown in FIG. 2, from which the porous structure of niobium nitride can be seen. Sample 8^#And sample 9^#Morphology andsample 3^#Similarly, assample 3^#As a typical representative, the scanning electron micrograph of the nano-porous niobium nitride single crystal is shown in FIG. 3, from which the porous structure of niobium nitride can be seen.

Sample M1^#Sample M11^#Scanning ofThe electron micrographs were respectively compared withsample 1^#Sample 11^#Similarly, as in sample M1^#Scanning electron micrograph of (1) and sample^#Similarly. Wherein the pore range of the product is within the range of 10 nm-1000 nm.

Example 9sample 1^#Sample 11^#Structural/elemental characterization of

Sample M1 was examined by X-ray crystallography and electron beam lithography combined with transmission electron microscopy^#Sample M3^#Sample 1^#Sample 11^#Atomic structure characterization was performed. X-ray powder diffraction phase analysis (PXRD) data were collected using a Rigaku MiniFlex600 powder diffractometer and illuminated using a Cu-Kalpha target reflection pattern

The test temperature is 293K, the 2 theta angle range is 5-65 degrees, the scanning step width is 0.02 degree, the current is 100mA, and the voltage is 30 KV. Transmission electron microscopy analysis was tested using (FEI Titan 3G 260-300) at 300 kV.

Sample M1^#Andsample 1^#The XRD diffractograms of fig. 4 and 5 are shown, respectively. Sample M1^#Andsample 1^#The XRD diffraction patterns of the materials have good consistency. Sample M2^#And M3^#Sample No. 2^#Sample 9^#XRD diffractogram of (1)^#Similarly. Sample M1^#Andsample 1^#The transmission electron micrographs of (A) are shown in FIG. 6 and FIG. 7, respectively. Sample M1^#Andsample 1^#The transmission electron micrographs have good consistency. Sample M2^#And M3^#Transmission electron micrograph and M1^#Similarly, sample 2^#Sample 9^#Transmission electron micrograph andsample 1^#Similarly.

The results show that these samples are all porous single crystals of niobium nitride.

Sample M1^#FIG. 8 is a scanning electron micrograph of a cross section. Sample M2^#And M3^#Scanning Electron microscopy of sections and sample M1^#Similarly.

Thus,sample 1 was obtained^#Sample 9^#All are niobium nitride single crystalSample M1^#Sample M3^#All are niobium nitride single crystal films.

Sample 10^#、11^#Andsample 1^#The XRD diffractograms of (1) have good consistency, except that because ofsample 10^#、11^#The doped transition metal element is a small amount, and the peak intensity is weak while the XRD diffraction pattern is reflected.

Example 10sample 1^#Sample 9^#Electrical property test of

In this example, sample No. 1 was used^#Sample 9^#The electrical properties of (a) were tested under the conditions of using the PPMS-9 system and a sample size of 2mm by 5mm by 0.5 mm. The test results are typically shown in fig. 9. FIG. 9 showssample 1^#Sample 3^#The electrical property test result of (1). As can be seen from the figure, the porous niobium nitride single crystal has excellent conductive performance, and the resistivity is 0.0003-0.0005 omega cm under the condition of normal temperature^-1。

Example 11sample 1^#Sample 9^#Catalytic performance test of

The porous single crystal nitride flow reactor was assembled by sealing sample # 1to sample # 9, respectively, in a stainless steel tube. The inlet of the flow reactor is controlled by a precision mechanical injector, and the outlet is vacuumized. The catalytic performance of the catalyst is evaluated within the range of 0.5-3 mm of the length of the reactor. An aqueous methanol solution (1:5) containing 8 wt% cyclooctene, 2 wt% internal standard (1-chlorobenzene), 6 wt% hydrogen peroxide was injected into a flow reactor at 60 ℃. Quantitative analysis was performed using a varian 450-GC/240-MS system. The reaction solution was evaporated to give a product, which was dissolved in deuterated chloroform, and subjected to HNMR spectroscopy using Jeol Z600 s. The oxidation product is 1,2 epoxycyclooctane, the conversion rate is more than 99 percent, and the selectivity is more than 99 percent.

Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.