1. A zinc oxide supporting heterogeneous metal oxide branch nano structure for enriching defective oxygen is characterized in that: zinc oxide (ZnO) is used as a nanorod with a branch structure, and heterogeneous metal oxide nanoparticles are loaded on the surface of the zinc oxide branch rod; wherein the diameter of the zinc oxide branch rod is 100-150nm, and the length is 200-400 nm; the diameter of the heterogeneous metal oxide nanoparticles is 5-40 nm.

2. The zinc oxide supported heterogeneous metal oxide branched nanostructure of claim 1, having a geometric topography characterized by: the multi-branch structure has the branch number of 1-20 and is in a branch flower shape.

3. The zinc oxide supported heterogeneous metal oxide branched nanostructure of claim 1, having a surface chemistry characterized by: the branched nano-structure material is enriched with defect oxygen, wherein the proportion of the defect oxygen in the oxygen element content in the material is 10-90%.

4. The chemical composition of the zinc oxide supported heterogeneous metal oxide branched nanostructure of claim 1, wherein: the metal oxide comprises cobaltosic oxide (Co)₃O₄) Copper oxide (CuO), chromium oxide (Cr)₂O₃) Nickel oxide (NiO), iron oxide (Fe)₂O₃) Tin dioxide (SnO)₂) Bismuth trioxide (Bi)₂O₃) Indium oxide (In)₂O₃) Cerium oxide (CeO)₂) Aluminum oxide (Al)₂O₃) And samarium oxide (Sm)₂O₃) Any one, two or more of them are mixed.

5. The method of claim 1, wherein the method comprises: zinc nitrate and metal salt are used as precursors.

6. The process of claim 1, wherein the preparation process comprises the following steps:

(1) hydrothermal method for preparing bimetal precursor

Adding 0.01-0.1M Cetyl Trimethyl Ammonium Bromide (CTAB) and 1-5M sodium hydroxide (NaOH) into water, mixing and stirring to obtain a solution A, then dropwise adding a certain amount of zinc nitrate hexahydrate and metal salt precursor mixed solution into the solution A, stirring for 0.5-3 hours to obtain a solution B, then transferring the solution B into a reaction kettle, and placing the reaction kettle in an oven at 80-200 ℃ for heat preservation for 4-24 hours to obtain a precursor C;

(2) calcining bimetallic precursors

And (3) placing the bimetallic precursor C in a muffle furnace at the temperature of 300-600 ℃ for calcination, wherein the heating rate is 1-10 ℃/min, and the calcination time is 2-20 hours.

7. The use of the zinc oxide supported heterogeneous metal oxide branched nanostructures of claim 1 as a sensitive material, wherein: the sensor is used for gas sensing, electrochemical sensing and biosensing of 3-hydroxy-2-butanone, isoprene, hydrogen sulfide, ethyl mercaptan, carbonyl sulfide, dimethyl sulfide and ammonia biomarkers and the like.

Background

In recent years, in the development process of the internet of things, the sensor plays an increasingly important role as a basic unit. In particular, the sensor can realize human health monitoring and food safety monitoring by accurately detecting trace biomarker gas exhaled by a human oral cavity, human sign signals (such as blood pressure, heart rate, body temperature and the like) or biological metabolites in body fluid and metabolic gas of food pathogenic bacteria in food, and is concerned by scientists and industries.

The food pathogenic bacteria and human body metabolites are various in types and can be selected as the markers of the sensor according to the abundance. For example, 3-hydroxy-2-butanone (3H-2B) is a metabolic gas of the food pathogen Listeria monocytogenes, and its content is about 32.18% at the maximum among many gases, and the food safety is detected by detecting the change in the concentration of 3H-2B. In another example, isoprene is a biomarker gas of non-alcoholic fatty liver disease, and the early diagnosis of chronic hepatitis is realized by analyzing and detecting isoprene in exhaled breath. By way of further example, hydrogen sulfide (H)₂S) and dimethyl sulfide are markers of liver diseases such as liver cirrhosis and hepatic coma and gastrointestinal diseases, and H in exhaled air is analyzed through detection₂The content of S and dimethyl sulfide realizes the monitoring and early diagnosis of the disease.

To date, scientists have conducted extensive research in an effort to achieve accurate detection of biomarkers. For example, BiVO is reported in journal of ACS Sensors, 8.8.2020₄The {010} surface of Pd is deposited to obtain Pd- {010} BiVO₄Decahedral microstructures (Gas sensor detecting 3-hydroxy-2-butanol biomakers: porous stress view decoding Pd nanoparticles from the {010} facets of BiVO₄decahedrons, ACS sensors.2020,5(8),2620-2627) was used to detect the metabolic marker 3H-2B of Listeria. As another example, a "highly sensitive and highly selective NiO/WO" was published in journal of ACS Sensors, 2 months 2021₃Composite nanoparticle detection halitosis biomarker H₂S' article describes WO for preparing modified NiO by using metal salt hydrolysis and subsequent hydrothermal process₃Nanoparticles (Highly inductive and selective NiO/WO)₃ composite nanoparticles in detecting H₂S biomararker of halitosis, ACS sensors.2021,6(3),733-741) for detecting human metabolic marker H₂S (halitosis).

Despite the progress of such research, there are still shortcomings that limit further industrialization. Firstly, the design and preparation of the sensitive material not only requires simple process, but also requires low cost, excellent repeatability, large yield and the like. Secondly, the sensitivity of the sensitive material to the biomarker needs to satisfy the basic requirements of moisture resistance, detection limit, selectivity, stability, sensitivity and the like at the same time, but the technical problem and the challenge are still remained.

Disclosure of Invention

The invention aims to overcome the defects in the prior sensitive material technology and invent a zinc oxide (ZnO) supported heterogeneous metal oxide branched nano structure with enriched defect oxygen, a preparation method and application thereof. Obtaining a ZnO supported heterogeneous metal hydroxide branched nano structure by a hydrothermal method, converting metal hydroxide into metal oxide by a high-temperature calcination process, and finally obtaining the ZnO supported heterogeneous metal oxide branched nano structure enriched in defective oxygen. The branched nano structure has the advantages of providing a large specific surface area, accelerating the electron transmission rate, increasing the potential barrier of a material contact interface and finally obtaining the enhanced sensing performance of the sensitive material.

The invention contents of the ZnO supported heterogeneous metal oxide branched nano structure are as follows:

the material of the heterogeneous metal oxide supported by ZnO comprises cobaltosic oxide (Co)₃O₄) Copper oxide (CuO), chromium oxide (Cr)₂O₃) Nickel oxide (NiO), iron oxide (Fe)₂O₃) Tin dioxide (SnO)₂) Bismuth trioxide (Bi)₂O₃) Indium oxide (In)₂O₃) Cerium oxide (CeO)₂) Aluminum oxide (Al)₂O₃) And samarium oxide (Sm)₂O₃) A mixture of any one, two or more of them.

The surface chemical state and geometric morphology characteristics of the sensitive material disclosed by the invention are that the ZnO supported heterogeneous metal oxide branched nano structure is rich in defect oxygen, wherein the proportion of the defect oxygen in the oxygen element content of the material is 10% -90%; the branched nano structure is composed of multi-branched (1-20 branched) nanorods, the diameter of the nanorods is 100-150nm, and the length of the nanorods is 200-400 nm; the metal oxide is nano-particle in geometric shape, the diameter is about 5-40nm, and the metal oxide is loaded on the surface of the ZnO branch nano-structure.

The branch nano structure of the ZnO supported heterogeneous metal oxide is prepared by taking zinc nitrate and metal salt as precursors, and the preparation process is as follows:

(1) hydrothermal method for preparing bimetal precursor

Adding 0.01-0.1M Cetyl Trimethyl Ammonium Bromide (CTAB) and 1-5M sodium hydroxide (NaOH) into water, mixing and stirring to obtain solution A, and adding a certain amount of zinc nitrate hexahydrate (Zn (NO)₃)₂·6H₂And O) dripping the mixed solution of the O) and the metal salt precursor into the solution A, stirring for 0.5-3 hours to obtain a solution B, transferring the solution B into a reaction kettle, and placing the reaction kettle in an oven at the temperature of 80-200 ℃ for heat preservation for 4-24 hours to obtain a precursor C.

(2) Calcining bimetallic precursors

And (3) placing the bimetallic precursor C in a muffle furnace at the temperature of 300-600 ℃ for calcination, wherein the heating rate is 1-10 ℃/min, and the calcination time is 2-20 hours.

The invention provides application of a ZnO-supported heterogeneous metal oxide branched nano-structure sensing material, which is applied to gas sensing, electrochemical sensing and biosensing for detecting biomarkers such as 3-hydroxy-2-butanone, isoprene, hydrogen sulfide, ethyl mercaptan, carbonyl sulfide, dimethyl sulfide, ammonia gas and the like. Supporting Co with ZnO₃O₄Branched nanostructures (ZnO/Co)₃O₄) In the case of gas sensing applications, for example, the following is illustrated:

(1) preparation of gas sensitive element

Weighing appropriate amount (10-100 mg) of ZnO/Co₃O₄Adding a proper amount of terpineol into the branched nano-structure sensing material, uniformly coating the slurry obtained after uniform stirring on the surface of the ceramic tube electrode, and finally placing the ceramic tube electrode in an oven for drying. Ceramic tube to be coated with sensitive material by solderingAnd the Ni-Cr alloy resistance wire is welded on a binding post of the gas-sensitive sensing base, and a Ni-Cr alloy resistance wire is inserted into the ceramic tube for regulating and controlling the working temperature.

(2) Sensing applications

ZnO/Co in the invention₃O₄The branched nano-structure sensing material has good sensing performance on 3H-2B. The reason is attributed to the fact that the branched nanostructures are enriched in defective oxygen, have a large specific surface area and rich gas diffusion paths. At the same time, ZnO and Co₃O₄The n-p heterojunction formed between the two increases the interface potential barrier, so that the material resistance is increased, and the pair of 3H-2B and H is formed₂The S has good gas-sensitive performance, and has important application prospects in detection of biomarkers such as listeria monocytogenes and the like, human health diagnosis and food safety monitoring.

Drawings

FIG. 1 shows ZnO/Co₃O₄Scanning electron micrographs of branched nanostructures; (b-c) transmission electron micrograph; (c)₁-c₄) And (4) element distribution diagram.

FIG. 2 shows ZnO/Co₃O₄The O1s X-ray photoelectron spectrum of the branched nano structure shows that the percentage of defect oxygen is 20.3 percent by peak fitting result, which indicates that the prepared ZnO/Co₃O₄Rich in defect oxygen.

FIG. 3 shows ZnO/Co₃O₄The branched nanostructures were exposed to different concentrations of (a)3H-2B and (B) H at 260 deg.C₂The sensing response of S.

Detailed Description

The invention is described below by means of specific embodiments. Unless otherwise specified, the technical means used in the present invention are well known to those skilled in the art. In addition, the embodiments should be considered illustrative, and not restrictive, of the scope of the invention, which is defined solely by the claims. It will be apparent to those skilled in the art that various changes or modifications in the components and amounts of the materials used in these embodiments can be made without departing from the spirit and scope of the invention. The raw materials and reagents used in the present invention are commercially available.

Example 1

(1) Hydrothermal method for preparing zinc-cobalt precursor

Adding 0.01M CTAB and 2.4M NaOH into water, mixing and stirring to obtain solution A, and adding 0.4MZn (NO)₃)₂·6H₂O with 0.05M cobalt nitrate hexahydrate (Co (NO)₃)₂·6H₂O) dropwise adding the mixed solution into the solution A, stirring for 1 hour to obtain a solution B, transferring the solution B into a reaction kettle, and placing the reaction kettle in an oven at 95 ℃ for heat preservation for 10 hours to obtain a precursor C.

(2) Calcining zinc cobalt precursor

And (3) calcining the zinc-cobalt precursor C in a 300 ℃ muffle furnace at the heating rate of 2 ℃/min for 12 hours.

Example 2

(1) Hydrothermal method for preparing zinc-copper precursor

Adding 0.02M CTAB and 2M NaOH into water, mixing and stirring to obtain solution A, and adding 0.4MZn (NO)₃)₂·6H₂O with 0.1M copper nitrate trihydrate (Cu (NO)₃)₂·3H₂O) dropwise adding the mixed solution into the solution A, stirring for 1 hour to obtain a solution B, transferring the solution B into a reaction kettle, and placing the reaction kettle in a 150 ℃ oven for heat preservation for 24 hours to obtain a precursor C.

(2) Calcining zinc-copper precursor

And (3) calcining the zinc-copper precursor C in a muffle furnace at 500 ℃, wherein the heating rate is 2 ℃/min, and the calcining time is 3 hours.

Example 3

(1) Hydrothermal method for preparing zinc-chromium precursor

Adding 0.01M CTAB and 2M NaOH into water, mixing and stirring to obtain solution A, and adding 0.4MZn (NO)₃)₂·6H₂O with 0.2M chromium nitrate nonahydrate (Cr (NO)₃)₃·9H₂O) dropwise adding the mixed solution into the solution A, stirring for 2 hours to obtain a solution B, transferring the solution B into a reaction kettle, and placing the reaction kettle in a 160 ℃ oven for heat preservation for 12 hours to obtain a precursor C.

(2) Calcining zinc-chromium precursor

And (3) calcining the zinc-chromium precursor C in a muffle furnace at 500 ℃, wherein the heating rate is 2 ℃/min, and the calcining time is 2 hours.

Example 4

(1) Hydrothermal method for preparing zinc-nickel precursor

Adding 0.01M CTAB and 2.4M NaOH into water, mixing and stirring to obtain solution A, and adding 0.5MZn (NO)₃)₂·6H₂O with 0.1M Nickel nitrate hexahydrate (Ni (NO)₃)₃·6H₂O) dropwise adding the mixed solution into the solution A, stirring for 2 hours to obtain a solution B, transferring the solution B into a reaction kettle, and placing the reaction kettle in a 120 ℃ drying oven for heat preservation for 6 hours to obtain a precursor C.

(2) Calcining zinc-nickel precursor

And (3) calcining the zinc-nickel precursor C in a muffle furnace at 500 ℃, wherein the heating rate is 2 ℃/min, and the calcining time is 2 hours.

Example 5

(1) Hydrothermal method for preparing zinc-iron precursor

Adding 0.02M CTAB and 2M NaOH into water, mixing and stirring to obtain solution A, and adding 1M Zn (NO)₃)₂·6H₂O with 0.2M iron nitrate nonahydrate (Fe (NO)₃)₃·9H₂O) dropwise adding the mixed solution into the solution A, stirring for 2 hours to obtain a solution B, transferring the solution B into a reaction kettle, and placing the reaction kettle in a 160 ℃ oven for heat preservation for 24 hours to obtain a precursor C.

(2) Calcining zinc-iron precursor

And (3) calcining the zinc-iron precursor C in a muffle furnace at the temperature of 300 ℃, wherein the heating rate is 2 ℃/min, and the calcining time is 2 hours.

Example 6

(1) Hydrothermal method for preparing zinc-tin precursor

Adding 0.01M CTAB and 1M NaOH into water, mixing and stirring to obtain solution A, and adding 0.4MZn (NO)₃)₂·6H₂O with 0.4M tin tetrachloride pentahydrate (SnCl)₄·5H₂O) dropwise adding the mixed solution into the solution A, stirring for 2 hours to obtain a solution B, transferring the solution B into a reaction kettle, and placing the reaction kettle in a 160 ℃ oven for heat preservation for 12 hours to obtain a precursor C.

(2) Calcining zinc-tin precursor

And (3) calcining the zinc-tin precursor C in a muffle furnace at 500 ℃, wherein the heating rate is 3 ℃/min, and the calcining time is 2 hours.

Example 7

(1) Hydrothermal method for preparing zinc bismuth precursor

Adding 0.01M CTAB and 2.4M NaOH into water, mixing and stirring to obtain solution A, and adding 0.5MZn (NO)₃)₂·6H₂O with 0.05M bismuth nitrate pentahydrate (Bi (NO)₃)₃·5H₂O) mixed solution (water: ethylene glycol 2: 1) dropwise adding the solution A into the solution A, stirring for 0.5 hour to obtain a solution B, transferring the solution B into a reaction kettle, and placing the reaction kettle in a 180 ℃ oven for heat preservation for 12 hours to obtain a precursor C.

(2) Calcining zinc bismuth precursor

And (3) calcining the zinc-bismuth precursor C in a muffle furnace at 500 ℃, wherein the heating rate is 5 ℃/min, and the calcining time is 3 hours.

Example 8

(1) Preparation of zinc-indium precursor by hydrothermal method

0.02M CTAB and 2.4M NaOH were added to water, mixed and stirred to obtain solution A, and then 0.5MZn (NO) was added₃)₂·6H₂O with 0.2M indium nitrate pentahydrate (In (NO)₃)₃·5H₂O) dropwise adding the mixed solution into the solution A, stirring for 1 hour to obtain a solution B, transferring the solution B into a reaction kettle, and placing the reaction kettle in a 100 ℃ oven for heat preservation for 24 hours to obtain a precursor C.

(2) Calcining zinc indium precursor

And (3) calcining the zinc-indium precursor C in a muffle furnace at 550 ℃, wherein the heating rate is 5 ℃/min, and the calcining time is 6 hours.

Example 9

(1) Hydrothermal method for preparing zinc-cerium precursor

Adding 0.01M CTAB and 2M NaOH into water, mixing and stirring to obtain solution A, and adding 0.1MZn (NO)₃)₂·6H₂O with 0.05M cerium chloride heptahydrate (CeCl)₃·7H₂And O) dropwise adding the mixed solution into the solution A, stirring for 1 hour to obtain a solution B, transferring the solution B into a reaction kettle, and placing the reaction kettle in a 180 ℃ oven for heat preservation for 4 hours to obtain a precursor C.

(2) Calcining zinc-cerium precursor

And (3) calcining the zinc-cerium precursor C in a 300 ℃ muffle furnace at the heating rate of 5 ℃/min for 2 hours.

Example 10

(1) Hydrothermal method for preparing zinc-aluminum precursor

Adding 0.01M CTAB and 1.5M NaOH into water, mixing and stirring to obtain solution A, and adding 0.5M 0.5MZn (NO)₃)₂·6H₂O and 0.1M aluminum sulfate (Al)₂(SO₄)₃) Dropwise adding the mixed solution into the solution A, stirring for 1 hour to obtain a solution B, transferring the solution B into a reaction kettle, and placing the reaction kettle in a 180 ℃ oven for heat preservation for 20 hours to obtain a precursor C.

(2) Calcining zinc-aluminium precursor

And (3) calcining the zinc-aluminum precursor C in a 600 ℃ muffle furnace at the heating rate of 5 ℃/min for 5 hours.

Example 11

(1) Hydrothermal method for preparing zinc samarium precursor

Adding 0.01M CTAB and 2.4M NaOH into water, mixing and stirring to obtain solution A, and adding 0.6MZn (NO)₃)₂·6H₂O with 0.2M samarium nitrate hexahydrate (Sm (NO)₃)₃·6H₂O) dropwise adding the mixed solution into the solution A, stirring for 1 hour to obtain a solution B, transferring the solution B into a reaction kettle, and placing the reaction kettle in a 200 ℃ oven for heat preservation for 8 hours to obtain a precursor C.

(2) Calcination of zinc samarium precursor

And (3) calcining the zinc samarium precursor C in a 600 ℃ muffle furnace at the heating rate of 5 ℃/min for 2 hours.