Preparation method of p-n homojunction cu2o glucose photoelectrochemical sensing electrode

Abstract

The application discloses a preparation method of a p-n homojunction cuprous oxide (Cu2O) glucose photoelectrochemical sensing electrode. In the photoelectrochemical three-electrode system, the working electrode is composed of a 1cm*3cm ITO substrate, the counter electrode is a platinum sheet electrode, and the saturated calomel electrode (SCE) is the reference electrode. Before use, all the ITO substrates are cleaned in acetone for 20 minutes, cleaned in ethanol for 20 minutes, and cleaned in deionized water for 20 minutes. The cuprous oxide (Cu2O) p-n homojunction film is deposited by using an aqueous solution containing 0.1M copper sulfate (CuSO4.5H2O) and 1.4M sodium lactate (C3H5O3Na) as a synthesis agent, the deposition solution is adjusted to pH=11 by NaOH, the potential of the solution relative to the SCE is set to-0.4V by using an electrochemical workstation, the deposition time is 1800s, the reaction deposition temperature is 30 DEG C, and thus the p-n homojunction cuprous oxide (Cu2O) glucose photoelectrochemical sensing electrode is obtained. 2+ The p-n homojunction cuprous oxide (Cu2O) glucose photoelectrochemical sensing electrode used in the application retains the high selectivity and high resistance to reduction of the p-type material as a photo-cathode electrode, and meanwhile, the p-n junction is modified by self-doping to improve the photoelectrochemical response of the electrode and enhance the signal strength. The application has the advantages of simple operation, safe and reliable reaction, low requirement on equipment, low cost of raw materials, and wide application.

Description

Technical Field

[0001] This invention belongs to the field of photoelectrochemistry and sensor applications, and specifically relates to a method for preparing a pn homojunction Cu2O glucose photoelectrochemical sensor. Background Technology

[0002] Glucose is the primary energy source for the normal functioning of the human body. Abnormal glucose levels in the body can lead to various related diseases such as diabetes and hypoglycemia, resulting in more serious health problems. Therefore, it is necessary to develop efficient and low-cost methods to quantify and monitor glucose in human serum and diet for clinical diagnosis and daily disease prevention. Photoelectrochemical sensors, as a further extension of electrochemical methods, offer simple and stable reaction processes with low background current, high sensitivity, and selectivity. Currently, a large portion of commercial glucose sensors are enzyme-based. However, enzyme-based sensors are often limited in use due to their sensitivity to environmental conditions (such as temperature and pH), low reproducibility, and high cost. Exploring non-enzyme glucose sensors that inherit the high selectivity and sensitivity of enzyme sensors is crucial. The choice of electrode materials plays a vital role in the design of enzyme-free sensors. Transition metals and their oxides, especially copper, have been explored as electrode materials due to their superior photo / electrocatalytic activity, low cost, natural abundance, and stability. Among various copper oxides, cuprous oxide (Cu₂O) is considered an efficient and low-cost p-type semiconductor for photoelectrochemical sensors, where p-type semiconductors are used as photocathode photoactive materials. Due to its resistance to reduction, it exhibits advantages in anti-interference capabilities, making it suitable for material detection applications. Introducing a pn homojunction allows for continuous band bending due to the Fermi level difference between semiconductors, resulting in rapid charge separation and transfer. In conclusion, highly valence-self-doped pn homojunctions represent a promising design approach for glucose sensors. Summary of the Invention

[0003] The purpose of this invention is to provide a photoelectrochemical glucose sensing electrode based on cuprous oxide (Cu2O). The electrode material prepared by this method not only retains the advantages of cuprous oxide (Cu2O) itself, but also endows the material with superior glucose detection performance.

[0004] The steps for preparing the cuprous oxide (Cu₂O)pn homojunction electrode according to the present invention are as follows:

[0005] Prepare and clean a 1cm × 3cm ITO substrate working electrode, a platinum counter electrode, and a saturated calomel electrode (SCE) as the reference electrode. Weigh out a certain amount of copper sulfate pentahydrate (CuSO4·5H2O) and sodium lactate (C3H5O3Na) to prepare 0.1M copper sulfate and 1.4M sodium lactate aqueous solutions. Prepare a sodium hydroxide (NaOH) solution and adjust the pH to 11 by adding it dropwise with a pipette. Set the solution potential relative to the SCE to -0.4V using an electrochemical workstation, the deposition time to 1800s, and the reaction deposition temperature to 30℃.

[0006] Specifically, the aqueous solution used for electrochemical deposition is prepared with copper sulfate pentahydrate (CuSO4·5H2O) and sodium lactate (C3H5O3Na). The reagents are common industrial products with a purity greater than 99%, widely available, easily purchased, and inexpensive.

[0007] Specifically, the water used to prepare the sedimentation aqueous solution is deionized water. The medicine is weighed according to the concentration requirements and mixed with a certain amount of deionized water, and then stirred thoroughly.

[0008] The pn homojunction cuprous oxide (Cu2O) glucose photoelectrochemical sensing electrode used in this invention exhibits superior detection performance compared to pure cuprous oxide (Cu2O), while retaining the material's inherent anti-interference ability and linear response to glucose, thus broadening the application of cuprous oxide in glucose detection. The electrolyte reaction in this invention can be performed entirely under normal pressure, making operation simple, with low raw material costs and minimal requirements for production equipment. Besides its performance in glucose detection, this material can also be used as a traditional photoelectrocatalyst, showing great promise for future applications.

[0009] The present invention has the following advantages:

[0010] (1) Excellent performance: The electrochemically deposited material has more active sites on the surface, and the grown film has uniform particle size and is not easy to fall off or deform. Its detection limit can reach 10 μM and has good linearity in the human blood glucose range of 1-10 mM, thus achieving good detection performance.

[0011] (2) The preparation method is simple, controllable, and easy to operate: The electrochemical deposition reaction of the aqueous solution in this invention is mild and controllable, with higher safety performance. The target product can be prepared simply by adjusting the solution ratio, V value, and deposition temperature. The electrode has demonstrated repeatability and stable performance in numerous experiments. We can achieve Cu content in the material by changing the deposition temperature. 2+ The degree of self-doping is adjusted to regulate electrode performance.

[0012] (3) The operating process mentioned in the method of this invention is conducive to rapid and high-quality electrode growth, and the operating conditions are easy to control, resulting in a high success rate. The entire preparation process does not require special conditions and has undemanding equipment requirements, making it suitable for large-scale production. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the glucose sensor device in this invention;

[0014] Figure 2 This is a photograph of the glucose sensing electrode used in this invention.

[0015] Figure 3 The following is a graph showing the results of linear sweep voltammetry at different glucose concentrations in this invention:

[0016] Figure 4 This is a chronoamperometry diagram of glucose being added under a 0V bias voltage during the dripping process in this invention.

[0017] Figure 5 This is a chronoamperometry diagram showing the process of adding glucose under a bias voltage of -0.3V in this invention. Detailed Implementation

[0018] The present invention will be further described in detail below through specific embodiments, wherein the raw materials are all industrially produced products. These embodiments are for illustrative purposes only and should not be construed as limiting the invention. Modifications or alterations of equivalent forms of the invention by those skilled in the art also fall within the scope defined by the appended claims.

[0019] Example 1:

[0020] Prepare and clean a 1cm × 3cm ITO substrate working electrode, a platinum sheet counter electrode, and a saturated calomel electrode (SCE) as the reference electrode. Weigh out a certain amount of copper sulfate pentahydrate (CuSO4·5H2O) and sodium lactate (C3H5O3Na) to prepare 0.1M copper sulfate and 1.4M sodium lactate aqueous solutions. Prepare a sodium hydroxide (NaOH) solution and add it dropwise using a pipette to adjust the pH of the deposition solution to 11. Set the potential of the solution relative to the SCE to -0.4V using an electrochemical workstation, the deposition time to 1800s, and the reaction deposition temperature to 30℃ to prepare a pn homojunction cuprous oxide (Cu2O) glucose photoelectrochemical sensing electrode. Assemble this electrode with the electrochemical workstation to form a testing device. Figure 1 This is a schematic diagram of the device. Figure 2 This is a photograph of the actual electrode. The electrode was tested using LSV-Linear Sweep Voltammetry on a Chi660D electrochemical workstation at temperatures ranging from 0.1 mM to 1.0 mM. Figure 3The results are from the linear sweep voltammetry method, which shows two linear regions: one at 0V bias and the other at -0.3V bias.

[0021] Example 2:

[0022] Prepare and clean the ITO substrate working electrode, platinum counter electrode, and saturated calomel electrode (SCE) as the reference electrode. Weigh out a certain amount of copper sulfate pentahydrate and sodium lactate to prepare 0.1M copper sulfate and 1.4M sodium lactate aqueous solutions. Prepare sodium hydroxide (NaOH) solution and add it dropwise using a pipette to adjust the pH of the deposition solution to 11. Set the potential of the solution relative to the SCE to -0.4V using an electrochemical workstation, the deposition time to 1800s, and the reaction deposition temperature to 30℃ to prepare the pn homojunction cuprous oxide (Cu2O) glucose photoelectrochemical sensing electrode. Prepare 0.1M KOH as the electrolyte solution, and switch the electrochemical workstation to chronoamperometry (it) detection at 0V bias. While adding glucose solution with a pipette, a timing current test was performed to achieve three concentration gradients of glucose in the reaction solution: 20μM-100μM (5 drops, each drop increasing by 20μM), 100μM-1mM (3 drops, each drop increasing by 0.3mM), and 1mM-11mM (5 drops, each drop increasing by 2mM). Figure 4 These are chronoamperometry results obtained during the glucose droplet addition process at 0V bias. We observed a linear relationship between photocurrent response and concentration across all three concentration regions. It exhibits good detection capability, with a linear correlation (R0) in the 20μM–100μM concentration range. 2 =0.92), 100μM-1mM concentration range, linear correlation (R) 2 =0.99), linear correlation (R²) in the 1mM-13mM concentration range. 2 =0.98). The experiment was conducted under a xenon lamp light source.

[0023] Example 3:

[0024] Prepare and clean the ITO substrate working electrode, platinum counter electrode, and saturated calomel electrode (SCE) as the reference electrode. Weigh out a certain amount of copper sulfate pentahydrate and sodium lactate to prepare a 0.1M copper sulfate and 1.4M sodium lactate aqueous solution. Prepare a sodium hydroxide (NaOH) solution and add it dropwise using a pipette to adjust the pH of the deposition solution to 11. Set the potential of the solution relative to the SCE to -0.4V using an electrochemical workstation, the deposition time to 1800s, and the reaction deposition temperature to 30℃ to prepare the pn homojunction cuprous oxide (Cu2O) glucose photoelectrochemical sensing electrode. Prepare 0.1M KOH as the electrolyte solution, and switch the electrochemical workstation to chronoamperometry (it) at a bias voltage of -0.3V. While adding glucose solution with a pipette, a timing current test was performed to achieve three concentration gradients of glucose in the reaction solution: 20μM-100μM (5 drops, each drop increasing by 20μM), 100μM-1mM (3 drops, each drop increasing by 0.3mM), and 1mM-13mM (6 drops, each drop increasing by 2mM). Figure 5 These are the chronoamperometry results obtained during the glucose droplet addition process at a bias voltage of -0.3V. We observed that the photocurrent response and concentration maintained a linear relationship in all three concentration regions, with better linearity in the 20μM-100μM concentration range, and a linear correlation (R0). 2 =0.92), 100μM-1mM concentration range, linear correlation (R) 2 =0.99), linear correlation (R²) in the 1mM-13mM concentration range. 2 =0.99). The experiment was conducted under a xenon lamp light source.

Claims

1. A method for preparing a p-n homojunction cuprous oxide (Cu2O) glucose photoelectrochemical sensing electrode, characterized in that, The steps are as follows: 1) In a photoelectrochemical three-electrode system, the working electrode is composed of a 1 cm x 3 cm ITO substrate, the counter electrode is a platinum sheet electrode, and the saturated calomel electrode (SCE) is the reference electrode; 2) Before use, all ITO substrates are ultrasonically cleaned in acetone for 20 minutes, in ethanol for 20 minutes, and in deionized water for 20 minutes; 3) The cuprous oxide (Cu2O) p-n homojunction thin film is deposited from an aqueous solution containing 0.1 M copper sulfate pentahydrate (CuSO4.5H2O) and 1.4 M sodium lactate (C3H5O3Na) as a synthesis agent, and the pH is adjusted to 11 by dropping NaOH with a pipette; 4) The three-electrode system is connected to an electrochemical workstation, the potential of the solution relative to the SCE is set to -0.4 V in the electrochemical workstation, the deposition temperature is controlled at 30°C, and the deposition time is set to 1800 s, thereby obtaining a p-n homojunction cuprous oxide (Cu2O) electrode.

2. The method of claim 1, wherein, Improvement on the traditional p-type semiconductor cuprous oxide (Cu2O) preparation process to realize Cu 2+ Self-doping generates p-n junction to improve photoelectric response, while retaining high selectivity of cuprous oxide (Cu2O) as a cathode active material.

3. The method of claim 1, wherein, Copper sulfate pentahydrate (CuSO4.5H2O), sodium lactate (C3H5O3Na), and sodium hydroxide (NaOH) are all commercially available industrial products with a purity of greater than 99%, and the water used to prepare the aqueous solution is deionized water.

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