CN112326754A - Detect Cu2+Of (2) a novel composite nanosystem - Google Patents

Abstract

The invention discloses a method for detecting Cu²⁺Doped TiO of₂@ AuNPs/CdS system. TiO doped with non-metallic elements by means of photoelectrochemical reaction systems₂The @ AuNPs/CdS is a photoelectric signal enhancement module for realizing the enhancement of Cu in the solution²⁺By rapid detection of Cu in solution²⁺The detection and the comparison of the result with the mature laboratory fluorescence spectrometry, the atomic absorption spectrometry and the like show that the detection method has simple sample pretreatment, less time consumption and accurate and reliable detection result, and the system can pass through CdS and Cu²⁺Formation of Cu on the surface of a material_xS promotes the recombination of photogenerated carriers and holes to cause obvious signal change, has lower detection limit and can be used for Cu in waste liquid²⁺And (3) carrying out rapid ultra-sensitive detection.

Description

Detect Cu2+Of (2) a novel composite nanosystem

Technical Field

The invention relates to the technical field of photoelectric detection, in particular to a method for detecting Cu²⁺Doped TiO of₂@ AuNPs/CdS system.

Background

Photoactive materials play a crucial role in PEC sensing, and rational design and fabrication of photoactive materials is one of the key steps in designing high-performance PEC sensors. PEC (photoelectrochemical) sensing is currently in a preliminary stage of development due to its short history of development compared to traditional electrochemical and spectroscopic analysis. There are also some key challenges to overcome and technical gaps to close, particularly in terms of achieving practical applications. In recent years, great progress has been made in the development of photoactive materials with excellent performance suitable for PEC sensing. With the overall trend of sensors in terms of miniaturization, multi-functionalization, intelligence and the like, reusable sensing elements and replaceable electronic elements may become structural features of future commercial products.

Elemental doping, which mainly includes anion doping, cation doping and co-doping, is considered as a simple and effective semiconductor physicochemical property control strategy, a matrix doped with an impurity element does not generate a new crystallographic phase, but it generally introduces a local electronic state between a mother band and a valence band, which can significantly change the separation of charge carriers and their recombination kinetics, the introduced impurity level provides a sub-band gap of two-step photoexcitation (from VB to the impurity level and from the impurity level to CB) by photons with lower energy than the original semiconductor band gap, and thus, the elemental doping generally causes red-shift of an absorption edge and improves the photoresponse of a semiconductor.

Although copper ions are essential in many reactions in physiological processes, they are harmful pollutants in wastewater discharged from metallurgical, metal processing, machine manufacturing, steel production, etc. processes, and abnormally take up Cu²⁺Various diseases such as Menkes disease, Wilson's disease, Alzheimer disease, Parkinson disease and the like can be caused, and excessive copper ions can remarkably inhibit the self-cleaning function of water, so that acute poisoning of aquatic organisms is caused. Therefore, it is of great significance to accurately and effectively detect the concentration of copper ions in the natural environment.

Disclosure of Invention

The invention provides a method for preparing a doped TiO₂@AuNPs/CdS system for detecting Cu in solution²⁺The method can be implemented in a laboratory without the need for cumbersome large-scale equipment support. The specific preparation scheme is as follows:

(1) synthesis of Br, N-codoped TiO₂: mixing 1-2 mL of butyl titanate (TBOT), 0.25-0.75 mL of ultrapure water and 30-40 mL of ethanol under vigorous stirring to obtain a uniform solution, reacting for 5-7h, and centrifuging to separate a large amount of TiO₂And dried at 50-70 ℃. Subsequently, the obtained bulk TiO₂(0.2-0.4 g) dispersed in a solvent comprising C₃H₆N₆(2-4mL, 0.1 g/mL), CTAB (2-4mL, 0.2 g/mL), and ultrapure water (40-60 mL), pouring 10-20 mL of ammonia water into the prepared mixed solution, sealing in a 90-110 mL high-pressure reaction kettle, and carrying out hydrothermal reaction at 140-160 ℃ for 22-24 h. Finally, centrifugally separating the obtained precipitate, and drying the precipitate at 70-90 ℃ in vacuum to obtain Br, N-codoped TiO₂For subsequent use;

(2) synthesis of Br, N-codoped TiO2@ AuNPs: 0.05-0.1 g Br, N-codoped TiO₂And 20-40 mL of ultrapure water, 100-₄Mixing, and subsequently, reacting NaBH₄(200-;

(3) preparing a photoelectric anode: thoroughly polishing a glassy carbon electrode by using 40-60 mm alpha-alumina powder, then washing with deionized water, performing ultrasonic treatment for 2-3 times by using ethanol, and then uniformly coating the obtained composite solution on a bare glassy carbon electrode;

(4) synthesizing Br, N-codoped TiO2@ AuNPs/CdS: in order to better modify CdS on the composite material photoelectric anode, the prepared composite material is soaked in a solution at 80 ℃ for 5-15 min, wherein the solution contains CdSO₄: thiourea: NH (NH)₄OH =1.5 mM: 75 mM: 0.95M, and storing the prepared composite material photoelectric anode in Ar atmosphere at 30-50 ℃;

(5) photoelectric detection pretreatment: is prepared prior to PEC detectionThe composite material heterojunction photoelectric anode is immersed in different Cu²⁺Concentration of Cu in solution (0, 0.5, 1, 5, 10, 50, 100, 500 and 1000. mu.M) for 3 min to complete the process²⁺And the interaction with CdS on the surface of the photoanode ensures the reliability of data under the same condition that each group of data is based on at least three repeated experiments in all PEC detection processes.

The invention has the beneficial effects that:

(1) the method has the advantages of low cost, simple experimental operation process and easily controlled reaction conditions;

(2) non-metal element doped TiO₂The @ AuNPs/CdS photoelectrode system has the advantages of good stability, strong visible light absorption capacity, high photocurrent density and excellent performance.

(3) Based on the doping of non-metal elements and the formation of II-type heterojunction, the visible light can be better absorbed, and the photoelectric current density is higher, thereby being more beneficial to the enhancement of photoelectric signals

The following is a description of detailed embodiments of the present invention: multifunctional RGO/BiVO₄-synthesis and application of Pt photoelectric material.

Example 1 (detection of Cu in solution)²⁺）

(1) Synthesis of Br, N-codoped TiO₂: 2 mL of butyl titanate (TBOT), 0.5 mL of ultrapure water and 40 mL of ethanol are mixed into a uniform solution under vigorous stirring, and after 6 hours of reaction, a large amount of TiO is centrifugally separated₂And dried at 60 ℃. Subsequently, the obtained bulk TiO₂(0.3 g) dispersed in a solvent comprising C₃H₆N₆(3 mL, 0.1 g/mL), CTAB (3 mL, 0.2 g/mL), and ultrapure water (50 mL), 10 mL of aqueous ammonia was poured into the prepared mixed solution, and the mixture was sealed in a 100 mL autoclave and subjected to hydrothermal reaction at 150 ℃ for 24 hours. Finally, the obtained precipitate is centrifugally separated and dried in vacuum at 80 ℃ to obtain Br, N-codoped TiO₂For subsequent use;

(2) synthesis of Br, N-codoped TiO2@ AuNPs: 0.05 g Br, N-codoped TiO₂And 30 mL of ultrapure water, 200. mu.L of 1% HAuCl₄Mixing, and subsequently, reacting NaBH₄(200 mu L, 0.095 g/mL) is quickly added into the mixed solution and stirred for 1 h to form a uniform solution, and the obtained solution is centrifuged, washed and dried (50 ℃) to obtain a Br and N-codoped TiO2@ AuNPs compound;

(3) preparing a photoelectric anode: thoroughly polishing a glassy carbon electrode by using 50 mm alpha-alumina powder, then washing with deionized water, performing ultrasonic treatment for 2-3 times by using ethanol, and then uniformly coating the obtained composite solution on a bare glassy carbon electrode;

(4) synthesizing Br, N-codoped TiO2@ AuNPs/CdS: in order to better modify CdS on the composite material photoelectric anode, the prepared composite material is soaked in a solution at 80 ℃ for 10 min, wherein the solution contains CdSO₄: thiourea: NH (NH)₄OH =1.5 mM: 75 mM: 0.95M, and storing the prepared composite material photoanode in an Ar atmosphere at 40 ℃;

(5) photoelectric detection pretreatment: immersing the prepared composite heterojunction photoanode into different Cu before PEC detection²⁺Concentration of Cu in solution (0, 0.5, 1, 5, 10, 50, 100, 500 and 1000. mu.M) for three minutes to complete the Cu²⁺And the interaction with CdS on the surface of the photoanode ensures the reliability of data under the same condition that each group of data is based on at least three repeated experiments in all PEC detection processes.

Claims (1)

1. The invention relates to a method for detecting Cu²⁺Doped TiO of₂The @ AuNPs/CdS system is characterized by comprising the following steps:

(1) synthesis of Br, N-codoped TiO₂: 2 mL of butyl titanate (TBOT), 0.5 mL of ultrapure water and 40 mL of ethanol are mixed into a uniform solution under vigorous stirring, and after 6 hours of reaction, a large amount of TiO is centrifugally separated₂And dried at 60 ℃. Subsequently, the obtained bulk TiO₂(0.3 g) dispersed in a solvent comprising C₃H₆N₆(3 mL, 0.1 g/mL), CTAB (3 mL, 0.2 g/mL), and ultrapure water (50 mL), 10 mL of aqueous ammonia was poured into the prepared mixed solution, and the mixture was sealed in a 100 mL autoclave and subjected to hydrothermal reaction at 150 ℃ for 24 hours.Finally, the obtained precipitate is centrifugally separated and dried in vacuum at 80 ℃ to obtain Br, N-codoped TiO₂For subsequent use;

(2) synthesis of Br, N-codoped TiO2@ AuNPs: 0.05 g Br, N-codoped TiO₂And 30 mL of ultrapure water, 200. mu.L of 1% HAuCl₄Mixing, and subsequently, reacting NaBH₄(200 mu L, 0.095 g/mL) is quickly added into the mixed solution and stirred for 1 h to form a uniform solution, and the obtained solution is centrifuged, washed and dried (50 ℃) to obtain a Br and N-codoped TiO2@ AuNPs compound;

(3) preparing a photoelectric anode: thoroughly polishing a glassy carbon electrode by using 50 mm alpha-alumina powder, then washing with deionized water, performing ultrasonic treatment for 2-3 times by using ethanol, and then uniformly coating the obtained composite solution on a bare glassy carbon electrode;

(4) synthesizing Br, N-codoped TiO2@ AuNPs/CdS: in order to better modify CdS on the composite material photoelectric anode, the prepared composite material is soaked in a solution at 80 ℃ for 10 min, wherein the solution contains CdSO₄: thiourea: NH (NH)₄OH =1.5 mM: 75 mM: 0.95M, and storing the prepared composite material photoanode in an Ar atmosphere at 40 ℃;

(5) photoelectric detection pretreatment: immersing the prepared composite heterojunction photoanode into different Cu before PEC detection²⁺Concentration of Cu in solution (0, 0.5, 1, 5, 10, 50, 100, 500 and 1000. mu.M) for three minutes to complete the Cu²⁺And the interaction with CdS on the surface of the photoanode ensures the reliability of data under the same condition that each group of data is based on at least three repeated experiments in all PEC detection processes.