CN-122016944-A - Single-particle nano-catalyst detection system and method based on quantum tunneling effect

Abstract

The invention provides a single-particle nano-catalyst detection system based on quantum tunneling effect, a detection method and application. The quantum tunneling electrode with a sub-5 nanometer gap is constructed as a sensing core, a functional layer is modified on the surface of the tunneling electrode, and a catalytic reaction of a single-particle nano catalyst is regulated by combining a gate potential, so that a conductance-electrochemistry signal joint characterization strategy is formed, in-situ capturing and identification of the single nano particle can be realized with extremely high signal to noise ratio, and physical properties and dynamic catalytic reaction information of the single nano particle can be synchronously acquired, so that a brand new technical scheme is provided for accurate and comprehensive characterization of the nano catalyst on the surface of the single molecular layer.

Inventors

• YI LONG
• TANG LONGHUA

Assignees

• 浙江大学

Dates

Publication Date

20260512

Application Date

20260413

Claims (10)

1. 1. The detection system of the single-particle nano catalyst is characterized by comprising tunneling electrodes, wherein the nano gaps of the tunneling electrodes are sub-5 nanometers, and the single-particle nano catalyst is bridged on the nano gaps of the tunneling electrodes through diffusion or enters between the nano gaps of the tunneling electrodes through diffusion.
2. 2. The detection system of claim 1, wherein the tunneling electrode has a nanogap of 1 to 3 nanometers and the single-particle nanocatalyst has a particle size of 1 to 50 nanometers.
3. 3. The detection system of claim 2, wherein the surface of the tunneling electrode is modified with a functionalized layer, the functionalized layer comprising an anti-adsorption functionalized layer for preventing adsorption of the single-particle nano-catalyst to the surface of the tunneling electrode during diffusion and/or a trapping functionalized layer for trapping the single-particle nano-catalyst with bubbles during catalytic reaction.
4. 4. The detection system of claim 3, wherein the anti-adsorption functionalized layer comprises any one or more of mercaptopropane, propyldisulfide, 6-mercapto-1-hexanol (MCH), 1-dodecanethiol, 1-octanethiol, 1-dodecanethiol, (3-aminopropyl) triethoxysilane, octadecylphosphoric acid, polyethylene glycol, polyacrylic acid, polystyrene sulfonic acid, and the capture functionalized layer comprises any one or more of mercaptopropionic acid, cysteine, aminopropyl triethoxysilane.
5. 5. The detection system of claim 4, wherein the surface of the tunneling electrode is modified to capture the functionalized layer when bubbles are generated during the catalytic reaction of the single-particle nanocatalyst, and wherein the surface of the tunneling electrode is modified to resist adsorption of the functionalized layer when bubbles are not generated during the catalytic reaction of the single-particle nanocatalyst.
6. 6. The detection system of claim 2, further comprising a weak current detection component electrically connected to the tunneling electrode for applying a bias to the tunneling electrode and detecting changes in tunneling current of the order of picoamps to femtoamps, and a gate potential regulation component for regulating the gate potential of the tunneling electrode.
7. 7. The detection system of claim 2, further comprising a reaction chamber, wherein the reaction chamber contains an electrolyte, the electrolyte comprising any one or more of phosphate buffer, acetate buffer, sodium perchlorate, potassium nitrate, and potassium chloride solution.
8. 8. A method for detecting a single particle nanocatalyst, characterized in that the detection is performed using a detection system according to any of claims 1-7, comprising the steps of: (1) Contacting the tunneling electrode with a sample solution containing a single-particle nano-catalyst to be tested; (2) The physical attribute information of the single-particle nano-catalyst is obtained by capturing a tunneling current signal generated by the diffusion bridge of the single-particle nano-catalyst on the nano-gap of the tunneling electrode or between the nano-gaps of the tunneling electrode.
9. 9. The method of claim 8, wherein the physical attribute information comprises any one or more of a core material, a modifying group, a size, and a solution environment of the single-particle nanocatalyst, and wherein step (1) comprises contacting the single-particle nanocatalyst with a sample solution that does not contain the single-particle nanocatalyst to be detected via a tunneling electrode to obtain the background signal.
10. 10. The method of claim 8, further comprising the step (3) of changing a gate potential of the tunneling electrode to excite the single-particle nano-catalyst to perform a catalytic reaction, capturing a tunneling current signal generated by the catalytic reaction of the single-particle nano-catalyst, and obtaining catalytic kinetic information of the single-particle nano-catalyst.

Description

Single-particle nano-catalyst detection system and method based on quantum tunneling effect Technical Field The invention relates to the technical field of single-particle nano-catalyst detection, in particular to a system and a method for detecting a single-particle nano-catalyst based on quantum tunneling effect. Background In the field of nano catalysis, accurately characterizing the physical properties and catalytic activity of a single nano-catalyst is critical to understanding its intrinsic performance and revealing the "structure-activity" relationship. Single-particle electrochemical characterization technology is an important research means in the field due to its high sensitivity, real-time monitoring capability and quantitative analysis potential. The traditional characterization of nanocatalysts, typically averaging the hundreds of millions of particle populations, masks individual differences among particles. The performance of nanocatalysts is not uniform, individual variation is precisely the key to understanding and optimizing their performance. The core causes of individual differences are numerous, such as differences in size, shape, surface state, microenvironment, etc. The average measurement results in blurred and distorted images, and the true structure-activity relationship cannot be revealed. By directly measuring the catalytic activity of single and definite nano particles and synchronously obtaining the physical properties of the nano particles, such as size, morphology, surface chemistry and the like, an accurate structure-performance corresponding relation can be established. For example, a 5nm icosahedron gold particle, the surface of which is modified with cysteine, can directly give an answer to the intrinsic conversion frequency of hydrogen peroxide decomposition under the condition of pH=7, and the group measurement cannot be achieved. Based on the real single-particle data, a synthesis scientist can be guided to accurately regulate and control synthesis parameters, the catalyst with a required high-performance structure can be prepared in batches, the catalyst can be developed into a single-particle-level catalyst screening chip in the future, the research and development period of a new catalytic material is greatly accelerated, and the catalyst has subversive potential. The detection of existing single-particle nano-catalysts usually adopts collision electrochemistry of microelectrodes, and usually relies on monitoring faraday current steps caused by random collision of particles to obtain catalytic activity information. However, such methods use macro-scale electrodes to cause extremely high background noise, so that detection of weak signals (such as small-sized and low-activity particles) is extremely difficult, only statistical electrochemical signals can be obtained, physical intrinsic properties (such as size and dielectric properties) of the same particle cannot be obtained synchronously, and non-specific adsorption of particles on the electrode surface is difficult to avoid, so that analysis fidelity of single particle events is insufficient. The detection lower limit of the method can only be about 5 nanometers, and in a conventional collision experiment, nanoparticles can be subjected to nonspecific adsorption or aggregation on the surface of an electrode, so that a plurality of particles react or signals overlap simultaneously, and the observed current step is difficult to ensure to originate from a definite and isolated single particle event, so that the accuracy of dynamics data interpretation is affected. By using a scanning tunneling microscope or a nanogap device, high-sensitivity detection of microscopic substances can be realized by monitoring electrical signals such as quantum tunneling current. However, these techniques are mostly focused on static conductance measurement in ultra-high vacuum or atmospheric environment, and are difficult to be directly used for in-situ and dynamic monitoring of liquid-phase catalytic reactions. At the same time, stable preparation of sub-5 nanogaps suitable for use in electrochemical systems still faces significant process challenges. To capture transient impact signals, electrodes on the order of micrometers or tens of nanometers are typically used. The larger electrode surface area results in excessive background capacitive current generated by the electric double layer charging. The weak faraday current variation (typically at pA level) generated by the nanocatalyst reaction is very prone to be submerged in background noise and difficult to effectively resolve, which fundamentally limits further improvement in detection signal-to-noise ratio and sensitivity. The current signal intensity is directly proportional to the electron transfer number in the catalytic reaction, and for the nano-catalyst with few reaction sites, extremely small size (< 5 nm) or slow catalytic dynamics (the electron transfer rate constant k 0