A method for Cr 3+ Modified nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2 nanomicrospheres, preparation method and application thereof

Abstract

The application discloses a kind of for Cr 3+ Modified nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2 Nanomicrosphere, its preparation method and application, solve the technical problems that Cr 3+ Detection mode cannot be accurately detected under low voltage and low content conditions.The present application first prepares praseodymium iron oxide Pr 0.5 Fe 0.5 O2 Nanomicrosphere, praseodymium chloride, ferric chloride, ammonium chloride and sodium dodecylbenzenesulfonate are added to ethylene glycol, and praseodymium iron oxide Pr 0.5 Fe 0.5 O2 Nanomicrosphere is prepared in a high-pressure reactor;Pr 0.5 Fe 0.5 O2 Nanomicrosphere is placed downstream of a tube furnace, and melamine is placed upstream, and the non-metallic nitrogen on the Pr 0.5 Fe 0.5 O2 Nanomicrosphere is doped by using the thermal decomposition of melamine, and nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2 Nanomicrosphere is prepared.In this way, a photoelectrochemical aptamer sensor is constructed for detecting trivalent chromium, and by combining the high sensitivity of the photoelectrochemical sensing material with the specific recognition technology of the nucleic acid aptamer, the sensitivity and accuracy of Cr 3+ Detection is significantly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photoelectric active materials and photoelectric sensors, in particular to a modified nitrogen-doped praseodymium iron oxide N-Pr 3+ for Cr 0.5 detection 0.5 O2 nanomicrosphere, a preparation method and application thereof. BACKGROUND

[0002] Chromium mainly exists in three valence states, namely Cr 2+ , Cr 3+ and Cr 6+ . These ionic forms have different stability and toxicity in the environment. Among them, Cr 3+ is relatively stable and has certain toxicity. Heavy metal Cr ions exist widely in natural environment, such as rocks, soil and water. Hexavalent chromium is toxic to the human body and is considered a carcinogen. Long-term exposure or ingestion of high concentrations of hexavalent chromium can cause damage to the lungs, kidneys and skeletal system. There have been many reports on the detection methods of hexavalent chromium. In contrast, trivalent chromium has lower toxicity, but under certain conditions it can also be converted into hexavalent chromium, thereby increasing its toxicity. Therefore, Cr 3+ has important influence on the environment and human health.

[0003] The traditional detection of trivalent chromium ions mainly relies on large instruments, most of which use atomic absorption spectrometry, voltammetry, surface plasmon field enhanced resonance light scattering and the recently popular colorimetric detection method, etc. Although these methods can detect trivalent chromium ions, they cannot detect trivalent chromium ions in real time and accurately due to their bulkiness or low precision. Moreover, the stability of the traditional photoelectric sensing platform for detecting trivalent chromium is generally poor, and it is difficult to accurately detect trivalent chromium at low voltage and low content.

[0004] In the prior art, the photoelectrochemical aptamer sensor is a biosensing platform that combines the high sensitivity of photoelectrochemical detection with the specific recognition technology of aptamers. Under light conditions, photoelectric materials absorb light energy and generate photoelectrons. These electrons are transferred and transmitted, eventually reaching the electrode and converting into an electrical signal. As a specific recognition element, aptamers can bind to target substances with high efficiency and specificity. When the target substance binds to the aptamer, it will change the surface state or electron transfer process of the photoelectric material, thereby triggering changes in photocurrent or photovoltage. Photoelectrochemical sensors have low background signals and low detection limits, enabling high-sensitivity detection of target substances. Aptamers, as biological recognition elements, have high specificity and biocompatibility, enabling precise identification of target substances. Photoelectrochemical aptamer sensors are easy to operate and can be easily automated and miniaturized. Compared with traditional detection methods, photoelectrochemical aptamer sensors have lower costs and faster detection speeds. Photoelectrochemical aptamer sensors have been widely used in biological analysis, food detection, environmental protection, and other fields. For example, in environmental detection, they can be used to detect harmful substances such as environmental estrogens and heavy metal ions; in biological analysis, they can be used to detect biomarkers such as cancer markers and disease-related proteins.

[0005] Therefore, there is an urgent need to provide a photoelectrochemical aptamer sensing platform that can achieve high-efficiency and high-sensitivity detection of Cr 3+ . SUMMARY

[0006] The present application provides a photoelectrochemical aptamer sensing platform for detecting Cr 3+ with high efficiency and high sensitivity. 3+ 0.5 Fe 0.5 O2 nanomicrosphere and its preparation method and application.

[0007] To achieve the above purpose, the present application is implemented by the following technical solutions: the present application provides a modified nitrogen-doped praseodymium iron oxide N-Pr 3+ Fe 0.5 O2 nanomicrosphere for detecting Cr 0.5 .

[0008] (1) Preparation of praseodymium iron oxide Pr 0.5 Fe 0.5 O2 nanomicrosphere:

[0009] ​A certain mass ratio of praseodymium chloride PrCl3, ferric chloride FeCl3, and ammonium chloride NH4Cl is weighed out, and a mixed solution is prepared using ethylene glycol. Sodium hexadecyl benzene sulfonate is added to the mixed solution, and after dissolution, the solution is placed in a polytetrafluoroethylene-lined high-pressure reaction kettle, and reacted at 120-220°C for 10-20 hours to obtain praseodymium iron oxide Pr 0.5 Fe 0.5 O2nanoparticles;

[0010] (2) Preparation of nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2nanoparticles:

[0011] The thermal decomposition of melamine is used to achieve the doping of non-metallic nitrogen on Pr 0.5 Fe 0.5 O2nanoparticles, and the praseodymium iron oxide Pr 0.5 Fe 0.5 O2nanoparticles prepared in step (1) is placed downstream of a tube furnace, and melamine is placed upstream of the tube furnace. The upstream of the tube furnace is heated from room temperature to 600-1200°C for reaction, and the downstream of the tube furnace is heated from room temperature to 1000-1200°C for reaction under a nitrogen atmosphere, to obtain nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2nanoparticles.

[0012] Preferably, step (3) is further included for preparing aminated nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2-NH2:

[0013] The nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2nanoparticles prepared in step (2) and 3-aminopropyl triethoxysilane are dispersed in an ethanol solution, and maintained at a temperature of 80-135°C for 20-40 minutes for reaction. After centrifugation, washing, and drying, aminated N-Pr 0.5 Fe 0.5 O2-NH2nanoparticles are obtained.

[0014] Preferably, step (1) for preparing praseodymium iron oxide Pr 0.5 Fe 0.5 O2nanoparticles includes the following specific steps:

[0015] The weight ratio of praseodymium chloride, ferric chloride, and ammonium chloride was weighed as follows: praseodymium chloride:ferric chloride:ammonium chloride = (2.2-10.0)g:(1.0-5.5)g:(2.0-10.0)g. This mixture was added to 500ml of ethylene glycol solvent to prepare a mixed solution. 1.0mg-100mg of sodium hexadecylbenzenesulfonate was added to the mixed solution, and after sonication, the mixture was placed in a high-pressure reactor lined with polytetrafluoroethylene. The reaction was carried out at 120℃-220℃ for 10-20 hours to obtain praseodymium iron oxide (Pr). 0.5 Fe 0.5 O2 nanospheres.

[0016] Preferably, step (2) involves preparing nitrogen-doped praseodymium iron oxide (N-Pr). 0.5 Fe 0.5 In O2 nanospheres

[0017] The praseodymium iron oxide Pr 0.5 Fe 0.5 The ratio of O2 nanospheres to melamine added is (2.0-10.0)g:(10.0-25.0)g;

[0018] Under a nitrogen atmosphere, the upstream of the tubular furnace is heated from room temperature to 600℃-1200℃ and held for 15min-60min, while the downstream of the tubular furnace is heated from room temperature to 1000℃-1200℃ and held for 60min-120min.

[0019] Preferably, step (3) prepares nitrogen-doped praseodymium iron oxide (N-Pr). 0.5 Fe 0.5 In O2-NH2, 10 mg of nitrogen-doped praseodymium iron oxide (N-Pr) was added. 0.5 Fe 0.5 O2 nanospheres were added to 20 ml of 3-aminopropyltriethoxysilane and dispersed in 100 ml of ethanol solution. After ultrasonic treatment for 30 min, the mixture was kept at 80℃-135℃ for 20 min.

[0020] The above is used for Cr 3+ Detected modified nitrogen-doped praseodymium iron oxide (N-Pr) 0.5 Fe 0.5 O2 nanospheres, modified nitrogen-doped praseodymium iron oxide (N-Pr) 0.5 Fe 0.5 O2 nanospheres are specifically amino nitrogen-doped praseodymium iron oxide (N-Pr). 0.5 Fe 0.5 O2-NH2 nanospheres with a diameter of 8 nm.

[0021] Used for Cr 3+ Detected modified nitrogen-doped praseodymium iron oxide (N-Pr) 0.5Fe 0.5 The application of O2 nanospheres can transform the aforementioned modified nitrogen-doped praseodymium iron oxide (N-Pr) 0.5 Fe 0.5 O2 nanospheres—Amino nitrogen-doped praseodymium iron oxide (N-Pr) 0.5 Fe 0.5 O2-NH2 nanospheres are used to prepare photoelectrochemical aptamer sensors, specifically for the detection of Cr. 3+ Photoelectrochemical sensors.

[0022] Preferably, Cr is detected 3+ Applications in photoelectrochemical sensors, using nitrogen-doped praseodymium iron oxide (N-Pr) 0.5 Fe 0.5 The preparation of the working electrode for the photoelectrochemical sensor using O2-NH2 includes the following specific steps:

[0023] (1) Take 5-20 mg of nitrogen-doped praseodymium iron oxide (N-Pr) 0.5 Fe 0.5 O2-NH2 nanospheres were dispersed in 50-200 mL of distilled water and ultrasonically dispersed to form a dispersion.

[0024] Take 6-20 μL of the dispersion and modify it on the ITO electrode, then air dry it at room temperature to form an ITO / N-Pr film. 0.5 Fe 0.5 O2-NH2 electrode;

[0025] (2) Add 1-10 μL of 2.5% glutaraldehyde solution and 1-5 μg / mL of specific Cr to the solution in sequence. 3+ The aptamer strand DNA1 forms ITO / N-Pr 0.5 Fe 0.5 O2-NH2 / DNA1 electrode;

[0026] (3) Then add 5-20 μL and 0.1 fg·mL dropwise in sequence. -1 ~10ng·mL -1 A series of different concentrations of Cr 3+ Cr was obtained by rinsing the solution with ultrapure water. 3+ Photoelectrochemical aptamer sensor ITO / N-Pr 0.5 Fe 0.5 O2-NH2 / DNA1-ITO / N-Pr 0.5 Fe 0.5 O2-NH2 / DNA1 / Cr 3+ .

[0027] Preferably, the specific detection method steps are as follows:

[0028] (1) An electrochemical workstation was used for testing with a three-electrode system, using a saturated calomel electrode as the reference electrode and a graphite electrode as the auxiliary electrode. The prepared Cr... 3+ The photoelectrochemical aptamer sensor was used as the working electrode, and the test was performed in PBS buffer solution with pH adjusted to 5.0-8.0 and concentration of 0.1mol / L-1.0mol / L.

[0029] (2) Using the time-current method to study Cr 3+ For testing, set the voltage to -0.2V to 0.2V, the running time to 30s to 80s, and the light source wavelength to 400nm to 550nm.

[0030] (3) Turn on the light source every 20 seconds for 20 seconds, record the photocurrent, and plot the working curve.

[0031] This invention provides a method for Cr 3+ Detected modified nitrogen-doped praseodymium iron oxide (N-Pr) 0.5 Fe 0.5 O2 nanospheres, their preparation methods, and applications. They possess the following beneficial effects:

[0032] (1) This invention prepares materials for Cr 3+ Detected modified nitrogen-doped praseodymium iron oxide (N-Pr) 0.5 Fe 0.5 O2 nanospheres possess excellent photoelectrochemical properties. In the field of photoelectrochemicals, they have a unique molecular structure and tunable energy level band gap. As electron acceptors and photogenerated charge transport mediators, they can effectively capture photogenerated electrons in semiconductor materials, thereby promoting charge separation and transport.

[0033] The introduction of nitrogen atoms introduces extra electrons into the material, forming negatively charged nitrogen-doped regions, thereby enhancing the material's conductivity. Nitrogen doping alters the surface structure and electronic properties of the material, thus improving its catalytic activity.

[0034] Ultimately, through the combined effect of nitrogen doping and praseodymium iron oxide, the material of this invention exhibits excellent photoelectrochemical properties. Under illumination, it can generate significant photocurrent and photovoltage responses, which is beneficial for applications in the field of photoelectrochemistry.

[0035] The multiple valence states and catalytic activity of praseodymium and iron also have a positive impact on catalytic performance; therefore, nitrogen-doped praseodymium iron oxide (N-Pr) 0.5 Fe 0.5 O2 exhibits remarkable catalytic performance and also demonstrates good stability under various conditions.

[0036] (2) This invention is used for Cr 3+ Detected modified nitrogen-doped praseodymium iron oxide (N-Pr)0.5 Fe 0.5 O2 nanomicrosphere, as a photoelectrochemical sensing material, is used to prepare a photoelectrochemical aptamer sensor, which utilizes photoelectrochemical principle to generate current or voltage response through light excitation as a detection signal, thereby significantly improving the accuracy and sensitivity of Cr 3+ detection.

[0037] Moreover, the specific reaction between the nucleic acid aptamer and the photoelectrochemical sensing material effectively avoids the interference of other substances on the detection, so that the sensor of the present application can accurately identify the target substance in a complex environment, significantly improves the accuracy of the detection, has a rapid response, can provide a detection result in a short time, and realizes the detection requirements of real-time monitoring and rapid response.

[0038] Compared with the traditional detection method, the present application realizes the purpose of rapid and ultra-sensitive detection of Cr 3+ under visible light conditions, the linear range of the detection of trivalent chromium is 0.1 fg·mL -1 -10 ng·mL -1 , the detection limit is 0.033 fg·mL -1 , and the detection concentration order of magnitude reaches 10 -17 g·mL -1 , while the detection limit of the conventional detection method is usually 10 -5 -10 -12 g·mL -1 , which is more sensitive. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a transmission electron microscope image of the N-Pr 0.5 Fe 0.5 O2 nanomicrosphere prepared in the present embodiment 1;

[0040] Figure 2 is a high-angle annular dark field scanning transmission electron microscope image of the N-Pr 0.5 Fe 0.5 O2 nanomicrosphere prepared in the present embodiment 1;

[0041] Figure 3 is a performance test image of the Cr 3+ photoelectrochemical aptamer sensor prepared in the present embodiment 2;

[0042] Figure 4 is a detection linear range test image of the Cr 3+ photoelectrochemical aptamer sensor in the present embodiment 3. DETAILED DESCRIPTION

[0043] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application.

[0044] Embodiment 1

[0045] Preparation of Cr 3+ Modified nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 The method for preparing Fe2O3nanomicrospheres comprises the following steps:

[0046] (1) Preparation of praseodymium iron oxide Pr 0.5 Fe 0.5 O2 nanomicrospheres

[0047] 5 g of praseodymium chloride, 2 g of ferric chloride, and 5 g of ammonium chloride are weighed by an electronic balance and configured into a mixed solution with 500 mL of ethylene glycol; 20 mg of sodium dodecylbenzenesulfonate is added to the mixed solution, and the solution is ultrasonically treated for 10 min, and then placed in a polytetrafluoroethylene-lined high-pressure reaction kettle for reaction at 120℃ for 20 h, so that praseodymium iron oxide Pr 0.5 Fe 0.5 O2 nanomicrospheres are obtained.

[0048] (2) Preparation of nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2 nanomicrospheres

[0049] The praseodymium iron oxide Pr 0.5 Fe 0.5 O2 nanomicrospheres prepared in step (1) above are taken, and 25.0 g of melamine is added to the downstream of a tubular furnace, and the upstream of the tubular furnace is heated from room temperature to 1200℃ under a nitrogen atmosphere, and the downstream of the tubular furnace is heated from room temperature to 1200℃, and the nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2 nanomicrospheres are obtained.

[0050] (3) Preparation of aminated nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2-NH2

[0051] 10 mg of the nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5O2 nanomicrosphere is dispersed into 100ml of ethanol solution, 20ml of 3-aminopropyl triethoxysilane is added, the above mixed solution is ultrasonically treated for 30min, and then is kept at 80-135 DEG C for 20min; finally, after centrifugation, washing and drying, the amino-functionalized N-Pr 0.5 Fe 0.5 O2 nanomicrosphere is dispersed into 100ml of ethanol solution, 20ml of 3-aminopropyl triethoxysilane is added, the above mixed solution is ultrasonically treated for 30min, and then is kept at 80-135 DEG C for 20min; finally, after centrifugation, washing and drying, the amino-functionalized N-Pr

[0052] As Figure 1 and Figure 2 The nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2 prepared in the embodiment has a diameter of 8nm. The material has a unique molecular structure and a tunable energy band gap, can be used as an electron acceptor and a photo-generated charge transport medium, can effectively capture photo-generated electrons in a semiconductor material, and thus promotes the separation and transmission of charges.

[0053] Meanwhile, the introduction of nitrogen atoms can change the lattice structure of the original oxide, introduce additional electrons in the material, form a negatively charged nitrogen-doped region, and the nitrogen doping also changes the magnetic properties of the praseodymium iron oxide due to the interaction between the nitrogen atoms and the atoms in the original lattice, thereby enhancing the electrical conductivity of the material. And the N-Pr 0.5 Fe 0.5 O2 prepared in the embodiment has a diameter of 8nm. The material has a unique molecular structure and a tunable energy band gap, can be used as an electron acceptor and a photo-generated charge transport medium, can effectively capture photo-generated electrons in a semiconductor material, and thus promotes the separation and transmission of charges.

[0054] The nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2 prepared in the embodiment has a diameter of 8nm. The material has a unique molecular structure and a tunable energy band gap, can be used as an electron acceptor and a photo-generated charge transport medium, can effectively capture photo-generated electrons in a semiconductor material, and thus promotes the separation and transmission of charges. 0.5 Fe 0.5 O2 prepared in the embodiment has a diameter of 8nm. The material has a unique molecular structure and a tunable energy band gap, can be used as an electron acceptor and a photo-generated charge transport medium, can effectively capture photo-generated electrons in a semiconductor material, and thus promotes the separation and transmission of charges.

[0055] Example 2

[0056] The nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5The O2 nanomicrosphere is applied to prepare a photoelectrochemical aptamer sensor, and the specific preparation method steps are as follows:

[0057] (1) 5 mg of N-Pr 0.5 Fe 0.5 O2-NH2 nanomicrosphere prepared in the embodiment 1 is dispersed in 50 mL of distilled water, and ultrasonic dispersion is performed for 30 min to form a dispersion liquid;

[0058] 6 μL of the dispersion liquid is taken and modified on an ITO electrode, and the ITO / N-Pr 0.5 Fe 0.5 O2-NH2 electrode is formed after being dried at room temperature to form a film.

[0059] (2) 5 μL of 2.5% glutaraldehyde solution and 1 μg / mL of specific recognition Cr 3+ nucleic acid aptamer chain DNA1 are sequentially added dropwise to form an ITO / N-Pr 0.5 Fe 0.5 O2-NH2 / DNA1 electrode.

[0060] (3) 5 μL of Cr -1 solution with different concentrations in the range of 0.1 fg·mL -1 -10 ng·mL 3+ is further added dropwise, and the photoelectrochemical aptamer sensor ITO / N-Pr 0.5 Fe 0.5 O2-NH2 / DNA1-ITO / N-Pr 0.5 Fe 0.5 O2-NH2 / DNA1 / Cr 3+ is prepared by washing with ultrapure water.

[0061] The room temperature in the embodiment of the application is 20-25℃.

[0062] The main components of the photoelectrochemical aptamer sensor prepared in the embodiment of the application are a photoelectrochemical converter and an aptamer sensor. The photoelectrochemical converter is used to convert light energy into electric energy to provide energy for the whole sensor. The aptamer sensor is a kind of biological molecule with high affinity, and is responsible for specifically recognizing and capturing target substances. When the target substances are combined with the aptamer, the photoelectrochemical signal inside the sensor changes, so that the detection of the target substances is realized.

[0063] The photoelectrochemical aptasensor adopted in the present application is an analysis method combining photoelectrochemical technology and aptamer recognition reaction principle. The electron-hole pairs generated after the photoelectrochemical sensing material absorbs energy form photocurrent or photovoltage through electron transfer. When the aptamer recognition reaction occurs, it will indirectly or directly change the original electric signal generated by the photoactive material. By monitoring the change of these electric signals, the quantitative determination of the target substance is realized.

[0064] As shown in Figure 3 , the photoelectrochemical aptasensor utilizes the principle of photoelectrochemistry to generate current or voltage response through light excitation as the detection signal. Since the excitation light source is separated from the detection signal, the background current is low, so the sensor has higher sensitivity. This high sensitivity enables the sensor to detect trace substances, improving the accuracy and reliability of the detection. Aptamer is a kind of biological molecule with high affinity, which can specifically recognize target substances. By screening and optimizing aptamer, specific recognition of target substances is realized, thereby avoiding interference of other substances.

[0065] This high selectivity enables the sensor to accurately identify target substances in complex environments, improving the accuracy of detection. Moreover, the photoelectrochemical aptasensor in the present application also has fast response speed. When the target substance binds with the aptamer, it will cause changes in the photoelectrochemical signal inside the sensor, which can be quickly detected. Therefore, the photoelectrochemical aptasensor can provide detection results in a short time, which is beneficial to real-time monitoring and rapid response.

[0066] Example 3

[0067] The photoelectrochemical aptasensor in Example 2 was applied to the detection of Cr 3+ , and the specific steps were as follows:

[0068] (1) The electrochemical workstation was used to test in a three-electrode system, with a saturated calomel electrode as the reference electrode, a graphite electrode as the auxiliary electrode, and the prepared Cr 3+ photoelectrochemical aptasensor as the working electrode. The test was carried out in a PBS buffer solution with pH of 7.4 and concentration of 0.5 mol / L;

[0069] (2) The Cr 3+ was detected by time-current method, the voltage was set to-0.1V, the running time was 60s, and the light source wavelength was 400nm;

[0070] (3) The light source was turned on every 20s for 20s, the photocurrent was recorded, and the working curve was drawn.

[0071] As shown in Figure 4 , the photoelectrochemical aptasensor for detecting Cr3+ N-Pr 0.5 Fe 0.5 The photoelectrochemical aptamer sensor of the O2 nanomicrosphere can detect Cr 3+ in a low voltage and low content, and the detection range of the photoelectrochemical aptamer sensor in the application is 0.1 fg·mL -1 -10 ng·mL -1 , and the detection limit is 0.033 fg·mL -1 The detection limit of Cr 3+ can reach 10 -17 g·mL -1 , and the detection limit of the conventional detection method is generally 10 -5 -10 -12 g·mL -1 .

[0072] Therefore, the photoelectrochemical aptamer sensor of the application is more sensitive than the detection method in the prior art. The photoelectrochemical aptamer sensor in the application solves the problem that the conventional Cr 3+ detection method cannot be used for low-content accurate detection, and the application scheme provides strong technical support for heavy metal ion detection in environmental water bodies in the future.

[0073] In summary, the modified nitrogen-doped praseodymium-iron oxide N-Pr 3+ Fe 0.5 O2 nanomicrosphere for Cr 0.5 detection and a preparation method and application thereof, through the synergistic effect of nitrogen doping and praseodymium-iron oxide, the material has excellent photoelectrochemical performance, and the photoelectrochemical aptamer sensor constructed by the nitrogen-doped praseodymium-iron oxide N-Pr 0.5 Fe 0.5 O2 nanomicrosphere can realize rapid and ultra-sensitive detection of Cr 3+ under visible light, has low cost, high selectivity, high sensitivity, rapid detection, is conducive to real-time monitoring and rapid response, and can be widely applied in the fields of magnetic materials, optical materials and catalytic materials.

[0074] The above is only an embodiment of the application, for example, the nitrogen-doped praseodymium-iron oxide N-Pr 0.5 Fe 0.5 O2 nanomicrosphere prepared by the application can also be applied in the field of magnetism, and can be used for preparing high-performance magnetic recording materials; can be applied in the field of optics, and can be used for preparing photocatalysts, optical sensors and the like; and can be applied in the field of catalysis, and can be used as a catalyst carrier or active component in a catalytic reaction.

[0075] Finally, although the present specification is described in terms of embodiments, not every embodiment exhibits every characteristic or implements every combination of features described in the present specification. The present specification has been described in a manner that is thorough and complete to one skilled in the art and the specification is intended to be construed as an exemplification of one or more embodiments rather than as an exhaustive list of embodiments.

Claims

1. A method for Cr 3+ modified nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2 nanomicrosphere, characterized in that, The steps include the following: (1) Pr-ferrite PrFeO4was prepared 0.5 Fe 0.5 O2nanospheres: A certain mass ratio of praseodymium chloride PrCl3, ferric chloride FeCl3, ammonium chloride NH4Cl is weighed, and a mixed solution is prepared by using ethylene glycol; sodium hexadecyl benzene sulfonate is added into the mixed solution, and after dissolution, the solution is placed in a high-pressure reaction kettle with a polytetrafluoroethylene lining, and is reacted at 120-220 ℃ for 10-20 h to obtain praseodymium-iron oxide Pr 0.5 Fe 0.5 O2 nanometer microspheres; (2) Preparation of nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2 nanospheres: The Pr 0.5 Fe 0.5 O2 nanospheres are placed downstream of a tube furnace, melamine is placed upstream of the tube furnace, and the upstream of the tube furnace is heated from room temperature to 600-1200°C for reaction, and the downstream of the tube furnace is heated from room temperature to 1000-1200°C for reaction under a nitrogen atmosphere, to obtain nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2 nanospheres are placed downstream of a tube furnace, melamine is placed upstream of the tube furnace, and the upstream of the tube furnace is heated from room temperature to 600-1200°C for reaction, and the downstream of the tube furnace is heated from room temperature to 1000-1200°C for reaction under a nitrogen atmosphere, to obtain nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2 nanospheres are placed downstream of a tube furnace, melamine is placed upstream of the tube furnace, and the upstream of the tube furnace is heated from room temperature to 600-1200°C for reaction, and the downstream of the tube furnace is heated from room temperature to 1000-1200°C for reaction under a nitrogen atmosphere, to obtain nitrogen-doped praseodymium iron oxide N-Pr 2. A method according to claim 1 for Cr 3+ Modified nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 A preparation method of O2 nanometer microspheres, characterized in that, Also included is step (3) of preparing the aminated nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2-NH2: The nitrogen-doped praseodymium iron oxide N-Pr prepared in step (2) is mixed with 3-aminopropyltriethoxysilane, and dispersed into an ethanol solution to react at a temperature of 80-135°C for 20-40 min. After centrifugation, washing, and drying, amino-functionalized N-Pr is obtained. 0.5 Fe 0.5 O2-NH2nanomicrospheres. 0.5 Fe 0.5 O2-NH2nanomicrospheres.

3. A method for Cr 3+ Modified nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 A preparation method of O2 nanometer microspheres, characterized in that, Step (1) Preparation of praseodymium iron oxide PrFeO2 0.5 Fe 0.5 The specific steps for preparing PrFeO2nanomicrospheres include the following: The weight ratio of praseodymium chloride, ferric chloride and ammonium chloride is praseodymium chloride:ferric chloride:ammonium chloride=(2.2-10.0)g:(1.0-5.5)g:(2.0-10.0)g, which is added into 500ml ethylene glycol solvent to configure a mixed solution, 1.0mg-100mg sodium hexadecyl benzene sulfonate is added into the above mixed solution, and after ultrasonic treatment, it is placed in a high-pressure reaction kettle with a polytetrafluoroethylene liner, and is reacted at 120℃-220℃ for 10h-20h to prepare praseodymium-iron oxide Pr 0.5 Fe 0.5 O2 nanometer microspheres.

4. A method according to claim 1 for Cr 3+ Modified nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 The preparation method of O2 nanometer microspheres, characterized in that, Step (2) Preparation of nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 In O2 nanospheres, The praseodymium iron oxide Pr 0.5 Fe 0.5 The ratio of the O2 nanomicrosphere to the melamine added amount is (2.0-10.0) g:(10.0-25.0) g. Under the nitrogen atmosphere, the upstream of the tube furnace is heated from room temperature to 600-1200 DEG C, and the downstream of the tube furnace is heated from room temperature to 1000-1200 DEG C, and the temperature is kept for 15-60 min and 60-120 min.

5. A method according to claim 2, wherein the Cr 3+ Modified nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 A preparation method of O2 nanometer microspheres, characterized in that, Step (3) Preparation of Amino-Functionalized Nitrogen-Doped Pr Iron Oxide N-Pr 0.5 Fe 0.5 O2-NH2, 10 mg of nitrogen-doped pr iron oxide N-Pr 0.5 Fe 0.5 O2nanoparticles were added to 20 ml of 3-aminopropyl triethoxysilane and dispersed in 100 ml of an ethanol solution. After ultrasonic treatment for 30 min, the reaction was incubated at a temperature of 80-135 °C for 20 min.

6. A method for Cr 3+ The modified nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2 nanomicrosphere, characterized in that, The Cr 3+ Detected modified nitrogen-doped praseodymium iron oxide (N-Pr) 0.5 Fe 0.5 The modified nitrogen-doped praseodymium iron oxide (N-Pr) was prepared by a method for preparing O2 nanospheres. 0.5 Fe 0.5 O2 nanospheres are specifically amino nitrogen-doped praseodymium iron oxide (N-Pr). 0.5 Fe 0.5 O2-NH2 nanospheres with a diameter of 8 nm.

7. A method for Cr 3+ The modified nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 The application relates to the application of O2 nanospheres, characterized in that, Modified nitrogen-doped praseodymium iron oxide N-Pr of claim 6 0.5 Fe 0.5 O2 nanospheres - aminated nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2-NH2 nanospheres for the preparation of a detection of Cr 3+ Photoelectrochemical aptamer sensor.

8. A method according to claim 7, wherein the Cr 3+ The modified nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 The application relates to the application of O2 nanospheres, characterized in that, Detection of Cr 3+ application in photoelectrochemical sensors of Cr, using aminated nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2-NH2to prepare a working electrode for photoelectrochemical sensors, comprising the specific steps as follows: (1) Take 5-20 mg of aminated nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 O2-NH2 nanomicrosphere is dispersed in 50-200 mL of distilled water, ultrasonic dispersion, and a dispersion liquid is formed; Take 6-20 μL dispersion liquid to modify on ITO electrode, dry at room temperature to form film, form ITO / N-Pr 0.5 Fe 0.5 O2-NH2 electrode; (2) Add 1-10 µL of 2.5% glutaraldehyde solution and 1-5 µg / mL of specific Cr-recognizing agent dropwise, respectively. 3+ The aptamer strand DNA1 forms ITO / N-Pr 0.5 Fe 0.5 O2-NH2 / DNA1 electrode; (3) 5~20 µL, 0.1 fg·mL -1 ~10 ng·mL -1 A series of different concentrations of Cr 3+ solution, prepared immediately after rinsing with ultrapure water Cr 3+ photoelectrochemical aptamer sensor ITO / N-Pr 0.5 Fe 0.5 O2-NH2 / DNA1-ITO / N-Pr 0.5 Fe 0.5 O2-NH2 / DNA1 / Cr 3+ .

9. A method according to claim 8, wherein the Cr 3+ The modified nitrogen-doped praseodymium iron oxide N-Pr 0.5 Fe 0.5 The application relates to the application of O2 nanospheres, characterized in that, The specific detection method steps are as follows: (1) The electrochemical workstation was used to test in a three-electrode system, and the saturated calomel electrode was used as the reference electrode, and the graphite electrode was used as the auxiliary electrode. The prepared Cr 3+ photoelectrochemical aptamer sensor was used as the working electrode, and the test was carried out in the PBS buffer with pH adjusted to 5.0-8.0 and concentration of 0.1 mol / L-1.0 mol / L. (2) Cr was detected by time-current method, the setting voltage was -0.2V-0.2V, the running time was 30s-80s, and the light source wavelength was 400nm-550nm; 3+ ; (3) Every 20 s, turn on the light source for 20 s, record the photocurrent, and draw the working curve.

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