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CN-122016958-A - Dynamic morphology and activity in-situ monitoring method for nitrate radical reduction reaction catalyst

CN122016958ACN 122016958 ACN122016958 ACN 122016958ACN-122016958-A

Abstract

The invention discloses a dynamic morphology and activity in-situ monitoring method of a nitrate radical reduction reaction catalyst, which belongs to the technical field of electrocatalytic material characterization, and realizes in-situ co-positioning accurate monitoring of nano morphology evolution and local activity distribution of the catalyst surface in the nitrate radical reduction reaction process by integrating an atomic force microscope, a scanning electrochemical microscope probe and an electrochemical workstation module and combining a modified electrolytic cell and a potential output-morphology scanning-activity detection linkage strategy, and has high stability and compatibility and excellent dynamic quantitative characterization capability. The in-situ monitoring method developed by the invention solves the technical bottleneck that the morphology and activity are difficult to synchronously monitor by the traditional characterization technology, and provides a brand-new dynamic analysis platform for dynamic identification of the active site of the nitrate radical reduction reaction catalyst, analysis of reaction mechanism and optimization of catalytic performance.

Inventors

  • GUO LIN
  • KANG JIANXIN
  • ZHAO YONG

Assignees

  • 北京航空航天大学

Dates

Publication Date
20260512
Application Date
20260310

Claims (10)

  1. 1. The method for monitoring the dynamic morphology and the activity of the nitrate radical reduction reaction catalyst in situ is characterized by comprising the following steps: Step 1, constructing and preprocessing a test system The method comprises the steps of preparing a conductive substrate coated with a nitrate radical reduction reaction catalyst, fixing a scanning electrochemical microscope probe on an atomic force microscope to obtain an atomic force microscope-scanning electrochemical microscope integrated probe, taking the integrated probe as a 1 st working electrode, taking the conductive substrate coated with the nitrate radical reduction reaction catalyst as a2 nd working electrode, injecting electrolyte to complete the assembly of an electrolytic cell, connecting the atomic force microscope-scanning electrochemical microscope integrated probe, an electrochemical workstation and a control computer, initializing a system and setting the lifting height and the detection potential of the integrated probe; step 2-in situ synchronous detection flow Setting potential programs of a 1 st working electrode and a 2 nd working electrode in electrochemical workstation software respectively, setting scanning parameters in atomic force microscope software, controlling lifting height of an atomic force microscope-scanning electrochemical microscope integrated probe through software to switch the probe between morphology scanning and lifting scanning modes, simultaneously starting morphology and current signal channels, recording contact current and lifting current of the integrated probe in real time, realizing synchronous acquisition of three-dimensional data of potential, morphology and activity, setting a storage path, and saving experimental data; step 3, morphology-activity correlation analysis and active site identification Analyzing surface morphology images under different potentials through software of an atomic force microscope to extract morphology features, simultaneously analyzing lifting current signals under each potential to establish a corresponding relation between the morphology features and the activity signals, and combining the morphology images of the atomic force microscope and an electrochemical current thermodynamic diagram to realize accurate positioning of active sites of the catalyst.
  2. 2. The method for monitoring the dynamic morphology and activity of a nitrate radical reduction reaction catalyst in situ according to claim 1, wherein the method for preparing the conductive substrate coated with the nitrate radical reduction reaction catalyst comprises the following steps: Adding absolute ethyl alcohol into nitrate radical reduction reaction catalyst powder with the thickness of 1-20 nm to prepare a dispersion liquid with the concentration of 0.1mg/mL, carrying out ultrasonic dispersion for 30min, taking 10 mu L of the dispersion liquid by a liquid-transferring gun, uniformly dripping the dispersion liquid on a conductive substrate, and carrying out vacuum drying at 60 ℃ for 2h to form a monodisperse catalyst coating, thereby obtaining the conductive substrate coated with the catalyst.
  3. 3. The method for in situ monitoring of dynamic morphology and activity of a nitrate reduction reaction catalyst according to claim 1, wherein the electrolytic cell comprises: the electrolyte device comprises a base (1), wherein the top of the base is fixedly connected with a shell (5) in a screwed manner, a sealed liquid space is formed between the base (1) and the shell (5), and electrolyte is contained in the liquid space; The inner tank body (4) is arranged at the top of the base (1), the inner tank body (4) is arranged in the liquid space, and an installation space is formed between the inner tank body (4) and the base (1); The bottom plate (2) is arranged in the installation space, a detachable electrode module (3) is arranged at the top of the bottom plate (2), and the bottom plate (2) and the inner tank body (4) are made of polytetrafluoroethylene; The quartz cover plate (7) is installed at the top of the shell (5), an O-shaped gasket (6) is installed between the quartz cover plate (7) and the shell (5), two interfaces are arranged on the O-shaped gasket (6), the interfaces are respectively connected with the Ag wire reference electrode and the Pt wire counter electrode, the tip of the Ag wire reference electrode is close to the working electrode and immersed in electrolyte, the Pt wire counter electrode is wound on the inner wall of the shell (5), the O-shaped gasket (6) is made of fluorinated rubber, and the interfaces are naturally sealed.
  4. 4. The method for monitoring the dynamic morphology and the activity of the nitrate radical reduction reaction catalyst in situ according to claim 3, wherein the immersion depth of the Ag wire reference electrode is 10mm.
  5. 5. The method for monitoring the dynamic morphology and activity of a nitrate reduction reaction catalyst in situ according to claim 3, wherein the electrode module supports a highly oriented pyrolytic graphite, gold-plated silicon wafer or glassy carbon electrode conductive substrate.
  6. 6. The method for monitoring the dynamic morphology and activity of the nitrate radical reduction reaction catalyst in situ according to claim 1, wherein the electrolyte in the step 1 is purged for more than 30 minutes by using argon in advance, sealed and stored in a low-temperature light-shielding manner.
  7. 7. The method for in-situ monitoring of dynamic morphology and activity of a nitrate reduction catalyst according to claim 1, wherein the conductive substrate coated with the nitrate reduction catalyst in step 1 has dimensions of 10mm x 10mm.
  8. 8. The method for monitoring the dynamic morphology and activity of a nitrate radical reduction reaction catalyst according to claim 1, wherein the lifting height of the integrated probe in the step 1 is 0-100 nm.
  9. 9. The method for in situ monitoring of dynamic morphology and activity of a catalyst for nitrate reduction reaction according to claim 1, wherein the detection potential of the integrated probe in step 1 is 0.6V vs. Ag.
  10. 10. The method for in-situ monitoring of dynamic morphology and activity of a catalyst for nitrate reduction reaction according to claim 1, wherein the scanning parameters in the step 2 are a scanning range of 5×5 μm, a scanning rate of 1.0Hz, a resolution of 256×256 pixels, and a scanning mode of peak force tapping mode.

Description

Dynamic morphology and activity in-situ monitoring method for nitrate radical reduction reaction catalyst Technical Field The invention relates to the technical field of electrocatalytic material characterization, in particular to a nitrate radical reduction reaction catalyst dynamic morphology and activity in-situ monitoring method. Background NO 3 RR (nitrate reduction reaction) is a key electrochemical process for solving nitrate pollution in water and realizing low-cost synthesis of "green ammonia", and the core of catalytic performance of the NO 3 RR depends on the dynamic evolution rule of the active sites (such as edges, folds, defect structures and the like) of the catalyst in the reaction process. Currently, characterization techniques for NO 3 RR catalysts rely mainly on commercial detection equipment alone or in simple combination, such as conventional electrochemical methods (e.g. cyclic voltammetry, electrochemical impedance spectroscopy) or spectroscopic techniques (e.g. X-ray absorption spectroscopy), and it is difficult to fully resolve dynamic changes in active sites. In order to break through the bottleneck, an Atomic Force Microscope (AFM) and a scanning electrochemical microscope (SECM) are combined, but the prior art still has the limitation in practical application, namely the dynamic complex scene of 'liquid phase electrocatalysis' of NO 3 RR is not adapted to static surface analysis (such as metal corrosion monitoring), the electrolytic cell design of the traditional EC-AFM-SECM device cannot meet the high alkaline environment (pH can reach 13) of NO 3 RR and is easy to cause electrode corrosion and electrolyte leakage, the adopted probe is mostly based on a feedback mode, the mode is single, the co-positioning of 'morphology-product detection' cannot be realized at the same time, and the probe size based on an ultra-microelectrode (UME) is large, so that the spatial resolution is poor, and the dynamic change of an active site is difficult to accurately identify. Disclosure of Invention Therefore, the invention aims to provide a dynamic morphology and activity in-situ monitoring method of a nitrate radical reduction reaction catalyst, which mainly aims to solve two major core defects in the detection technology of a NO 3 RR catalyst based on a commercial module, namely space-time disjointing of morphology characterization and activity detection and scene suitability loss. In order to achieve the above purpose, the present invention is realized by the following technical scheme: (1) Integrating AFM, SECM probes and electrochemical workstations, realizing in-situ co-location monitoring of the nano morphology evolution and the local activity distribution of the catalyst in the NO 3 RR process, and breaking the space-time decoupling of the structure and the activity; (2) Slight modification and operation optimization of the electrolytic cell are carried out, a testing environment (a liquid phase system, pH compatibility: 1-13) adapting to NO 3 RR is constructed, and stability and repeatability of an active signal are ensured; (3) Designing a triple-linkage strategy of potential output-morphology scanning-activity detection, and accurately capturing morphology and activity synchronous change of a NO 3 RR key potential interval; (4) The universality of the device is improved, so that the device can be expanded to the representation of various electrocatalysts. Specific: a nitrate radical reduction reaction catalyst dynamic morphology and activity in-situ monitoring method comprises the following steps: Step 1, constructing and preprocessing a test system Fixing a scanning electrochemical microscope (SECM) probe on an Atomic Force Microscope (AFM) to obtain an Atomic Force Microscope (AFM) -scanning electrochemical microscope (SECM) integrated probe, taking the integrated probe as a 1 st working electrode, taking the conductive substrate coated with the nitrate reduction catalyst as a 2 nd working electrode, injecting electrolyte to complete the assembly of an electrolytic cell, connecting the Atomic Force Microscope (AFM) -scanning electrochemical microscope (SECM) integrated probe, an electrochemical workstation and a control computer, initializing a system and setting the lifting height and the detection potential of the integrated probe; step 2-in situ synchronous detection flow Setting potential programs of a1 st working electrode and a2 nd working electrode in electrochemical workstation software respectively, setting scanning parameters in atomic force microscope software, controlling the lifting height of an Atomic Force Microscope (AFM) -scanning electrochemical microscope (SECM) integrated probe through software to switch between morphology scanning and lifting scanning modes, simultaneously starting morphology and current signal channels, recording contact current and lifting current of the integrated probe in real time, realizing synchronous acquisition of three-dimensional data