In-situ Raman spectrum pool for detecting three-phase interface in electrochemical reaction process in real time

Abstract

An in-situ Raman spectrum pool for real-time detection of a three-phase interface in an electrochemical reaction process belongs to the field of electrochemical characterization, and the reaction pool can detect the change of the three-phase interface on the surface of a catalyst in the electrochemical reaction process in real time, and explores a reaction mechanism and understands a reaction path by analyzing a Raman spectrum. The in-situ Raman spectrum pool comprises an upper cover plate, a quartz glass observation window, an in-situ Raman module, a reference electrode (Ag / AgCl), a cathode chamber module, a cathode material, an anode chamber module, a counter electrode (platinum wire), an ion exchange membrane and a rubber sealing ring. A quartz glass observation window is arranged between the upper cover plate and the in-situ Raman module; a cathode material is arranged between the in-situ Raman module and the cathode module; an ion exchange membrane is arranged between the in-situ Raman module and the anode module; and the in-situ Raman module is a custom module used for various test conditions. The in-situ Raman test device has the advantages that the in-situ Raman test (0-400 mA / cm < 2 >) under the current density in a larger range can be carried out, and the in-situ Raman test device plays an important role in exploration of a reaction mechanism and a reaction path and design and development of a catalyst.

Description

Technical Field

[0001] The utility model belongs to the field of electrochemical characterization, and particularly relates to an in-situ Raman spectroscopy cell for real-time detection of the three-phase interface during the electrochemical reaction process, which is used for real-time detection of the changes of the three-phase interface on the catalyst surface during the electrocatalytic reaction process, so as to explore the reaction mechanism and understand the reaction path. Background Technique

[0002] The normal operation of human society requires the supply of fossil energy. However, the consumption of fossil energy has led to energy shortages and environmental pollution. The method of reducing greenhouse gases such as CO 2 , NO, etc. into CO, ethanol, ammonia and other high-value chemical raw materials can not only alleviate the increasingly tense environmental problems, but also generate certain economic value. In the field of electrocatalysis, researchers have been committed to designing and developing catalysts with high target product selectivity. In order to explore the reaction mechanisms of different catalysts and the surface adsorption conditions of intermediates, in-situ electrochemical testing methods for characterization have received more and more attention. As a scattering spectroscopy technology applied to the analysis of material structures, Raman spectroscopy technology obtains information on molecular vibrations, chemical bond formation and breakage by analyzing the scattering spectra with different incident light frequencies, providing data and theoretical support for studying the reaction mechanism.

[0003] During the in-situ Raman test process, the rationality of the design of the in-situ Raman spectroscopy cell plays a decisive role. The existing Raman spectroscopy cells for in-situ characterization usually need to be customized, and there is a large gap from the electrolytic cells used in the actual experimental performance test process. Especially in terms of current density, it is usually small, making it difficult to accurately characterize the actual test conditions. On the one hand, this restricts the development of the field of electrochemical in-situ Raman characterization, and on the other hand, it also brings challenges to the analysis of experimental results and reaction mechanisms.

[0004] Therefore, there is an urgent need for an in-situ Raman spectroscopy cell that is more suitable for actual test conditions to detect the three-phase interface during the electrochemical reaction process in real time to solve the above problems. Content of the Utility Model

[0005] The purpose of the utility model is to design an in-situ Raman spectroscopy cell that more conforms to the actual test conditions to overcome a series of defects existing in the existing Raman spectroscopy cells, which is used to detect the types of intermediates and molecular vibration conditions on the surfaces of different catalysts in real time during the electrocatalytic process, so as to provide a theoretical basis for catalyst evaluation.

[0006] The purpose of the utility model can be realized by the following technical solutions:

[0007] An in-situ Raman spectroscopy cell for real-time detection of the three-phase interface during the electrochemical reaction process in the present utility model includes: an upper cover plate, an in-situ Raman module, a cathode chamber module, and an anode chamber module, which are connected in sequence;

[0008] A quartz glass observation window is provided between the upper cover plate and the in-situ Raman module;

[0009] A cathode material is provided between the in-situ Raman module and the cathode chamber module;

[0010] An ion exchange membrane is provided between the in-situ Raman module and the anode chamber module;

[0011] For the in-situ Raman module, the user can select the material of the gas diffusion layer and the type of catalyst according to the actual test requirements;

[0012] Further, the quartz glass observation window is made of high-purity and high-light transmittance silica quartz glass with a thickness of 0.5 - 1 mm;

[0013] Further, the cathode material is various gas diffusion electrodes loaded with different catalysts;

[0014] Further, the cathode material is connected to the working electrode of the electrochemical workstation through a conductive copper tape;

[0015] Further, the reference electrode (Ag / AgCl) is fixed in the electrolyte cavity of the in-situ Raman module and is connected to the reference electrode of the electrochemical workstation;

[0016] Further, the counter electrode (platinum wire) is fixed in the electrolyte cavity of the anode chamber module and is connected to the auxiliary electrode of the electrochemical workstation;

[0017] Further, the in-situ Raman module includes:

[0018] The in-situ Raman module body;

[0019] The in-situ Raman module gas chamber, which is opened at the bottom of the in-situ Raman module body;

[0020] The in-situ Raman module electrolyte cavity, which is opened in the middle of the in-situ Raman module body and is filled with electrolyte;

[0021] The in-situ Raman module and the anode chamber module are sealed for gas and electrolyte through a third rubber seal ring and a nut;

[0022] The upper cover plate and the in-situ Raman module are sealed for gas and electrolyte through the first rubber seal ring and a nut;

[0023] The cathode chamber module and the in-situ Raman module achieve the sealing of gas and electrolyte through the second rubber sealing ring and nuts;

[0024] The in-situ Raman module electrolyte inlet channel is opened on the side of the in-situ Raman module, close to the ion exchange membrane side, and is connected to the in-situ Raman module electrolyte cavity and the peristaltic pump;

[0025] The in-situ Raman module electrolyte outlet channel is opened on the side of the in-situ Raman module, far from the ion exchange membrane side, and is connected to the in-situ Raman module electrolyte cavity;

[0026] Further, the cathode chamber module includes:

[0027] The cathode chamber body;

[0028] The cathode chamber gas cavity and the serpentine flow channel are opened on the top of the cathode chamber body, and the serpentine flow channel is responsible for guiding the gas flow direction;

[0029] The cathode chamber gas inlet channel is opened on the side of the cathode chamber body and is connected to the cathode chamber gas cavity and the gas flow controller;

[0030] The cathode chamber gas outlet channel is opened on the side of the cathode chamber body and is connected to the cathode chamber gas cavity;

[0031] Further, the anode chamber module includes:

[0032] The anode chamber body;

[0033] The anode chamber electrolyte cavity is opened in the middle of the anode chamber body, and is filled with electrolyte;

[0034] The anode chamber electrolyte inlet channel is opened on the top of the anode chamber body and is connected to the anode chamber electrolyte cavity and the peristaltic pump;

[0035] The anode chamber electrolyte outlet channel is opened on the side of the anode chamber body and is connected to the anode electrolyte cavity;

[0036] When the in-situ Raman spectrochemical cell operates, the reaction gas enters the in-situ Raman module atmosphere from the gas inlet channel of the cathode chamber module through the gas flow controller. Then, a part of the reaction gas flows out from the cathode chamber module gas outlet channel, and another part of the reaction gas reaches the surface of the cathode material through the cathode chamber serpentine flow channel and the gas diffusion layer to participate in the reaction;

[0037] Further, the upper cover plate and the three modules of the in-situ Raman spectrochemical cell are sealed by rubber sealing rings and external nuts, and the material of the rubber sealing ring is selected according to different electrolyte types;

[0038] Further, the upper cover plate of the in-situ Raman spectroscopy cell and the materials used for the three modules are all acid- and alkali-resistant polyether ether ketone (PEEK).

[0039] Further, the ion exchange membrane is an anion exchange membrane, a cation exchange membrane or a bipolar membrane.

[0040] Compared with the existing in-situ Raman test cell, the present utility model has the following advantages:

[0041] (1) The test current density of the in-situ Raman spectroscopy cell of the present invention can reach up to 400 mA / cm 2 , broadening the testable range of the current in-situ Raman test cell, making the parameters in the in-situ Raman characterization experiment closer to the conditions in the actual test process, and the experimental data more representative. It provides effective information for researchers to explore the reaction mechanism, path, the adsorption situation of intermediates, and the development and evaluation of catalysts.

[0042] (2) The reaction device of the in-situ Raman spectroscopy cell of the present invention is modular, simple and convenient to use. Users can select different cathode materials, ion exchange membranes and electrolytes according to the actual situation. The in-situ Raman spectroscopy cell is suitable for acid, alkali and neutral reaction systems, and can simultaneously perform in-situ Raman tests on carbon dioxide reduction, carbon monoxide reduction, nitric oxide reduction and other reducible gases and the co-reduction of the above gases, with a wide range of applications.

[0043] (3) The in-situ Raman spectroscopy cell of the present invention can achieve high-sensitivity real-time monitoring of the changes in the three-phase interface of the catalyst, thus providing important data support for analyzing the reaction active sites, the types of adsorbed intermediates and the surface microenvironment of the catalyst. Description of the Drawings

[0044] Figure 1 It is an overall view of an in-situ Raman spectroscopy cell for real-time detection of the three-phase interface during an electrochemical reaction process included in the present utility model.

[0045] Figure 2 It is a construction decomposition view of an in-situ Raman spectroscopy cell for real-time detection of the three-phase interface during an electrochemical reaction process included in the present utility model.

[0046] Figure 3 It is an in-situ Raman spectrogram of an in-situ Raman spectroscopy cell for real-time detection of the three-phase interface during an electrochemical reaction process in an open embodiment of the present utility model during the electrochemical carbon dioxide reduction process. Description of the Drawings:

[0048] 1. Upper cover plate, 2. Quartz glass observation window, 4. In-situ Raman module, 5. Reference electrode, 7. Cathode chamber module, 8. Anode chamber module, 9. Counter electrode, 10. Ion exchange membrane, 12. Cathode material, 3, 6, 11. Rubber sealing rings. Detailed implementation mode

[0049] The present utility model will be described in detail below in conjunction with the accompanying drawings and specific implementation cases.

[0050] An in-situ Raman spectroscopy cell for real-time detection of the three-phase interface during the electrochemical reaction process in this implementation case includes, which are connected in sequence: upper cover plate 1, in-situ Raman module 4, cathode chamber module 7, anode chamber module 8 and other accessories. For details, see Figure 2 .

[0051] A quartz glass observation window 2 is provided between the upper cover plate 1 and the in-situ Raman module 4, and a cathode material 12 is provided between the in-situ Raman module 4 and the cathode chamber module 7. The cathode material 12 is connected to the working electrode of the electrochemical workstation through a conductive copper tape. The reference electrode (Ag / AgCl) 5 is placed inside the electrolyte cavity of the in-situ Raman module and is connected to the reference electrode of the electrochemical workstation. An ion exchange membrane 10 is provided between the in-situ Raman module 4 and the anode chamber module 8, and the counter electrode (platinum wire) 9 is horizontally placed inside the electrolyte cavity of the anode chamber module and is connected to the auxiliary electrode of the electrochemical workstation.

[0052] The in-situ Raman module 4 includes: an in-situ Raman module body, an in-situ Raman module gas chamber, an in-situ Raman module electrolyte cavity, an in-situ Raman module electrolyte inlet channel, and an in-situ Raman module electrolyte outlet channel. Among them, the in-situ Raman module gas chamber is opened at the bottom of the in-situ Raman module body; the in-situ Raman module electrolyte cavity is opened in the middle of the in-situ Raman module body, and the electrolyte is filled therein; the in-situ Raman module electrolyte inlet channel is opened on the side of the in-situ Raman module body and is connected to the Raman module electrolyte cavity and the peristaltic pump; the in-situ Raman module electrolyte outlet channel is opened on the side of the in-situ Raman module body and is connected to the Raman module electrolyte cavity.

[0053] The cathode chamber module 7 includes: a cathode chamber body, a cathode chamber gas cavity and a serpentine flow channel, a cathode chamber gas inlet channel, and a cathode chamber gas outlet channel. Among them, the cathode chamber gas cavity and the serpentine flow channel are opened at the top of the cathode chamber body and are responsible for controlling the gas flow direction. A cathode material 12 is provided between the cathode chamber gas cavity and the serpentine flow channel and the in-situ Raman module gas chamber; the cathode chamber gas inlet channel is opened on the side of the cathode chamber body and is connected to the cathode chamber gas cavity and the gas flow controller; the cathode chamber gas outlet channel is opened on the side of the cathode chamber body and is connected to the cathode chamber gas cavity;

[0054] The anode chamber module 8 includes: a cathode chamber body, an anode chamber electrolyte cavity, an anode chamber electrolyte inlet channel, and an anode chamber electrolyte outlet channel. Among them, the anode chamber electrolyte cavity is opened in the middle of the anode chamber body, and is separated from the in-situ Raman module electrolyte cavity by an ion exchange membrane 10; the anode chamber electrolyte inlet channel is opened at the top of the anode chamber body and is connected to the anode chamber electrolyte cavity and the peristaltic pump; the anode chamber electrolyte outlet channel is opened on the side of the anode chamber body and is connected to the anode chamber electrolyte cavity.

[0055] In this example, carbon dioxide is selected as the reaction gas. After assembling an in-situ Raman spectroscopy cell for real-time detection of the three-phase interface during the electrochemical reaction, it is as Figure 1 shown. The manufacturing materials of the upper cover plate and the three modules are all polyether ether ketone (PEEK).

[0056] Between each module, rubber sealing rings and external nuts are used for sealing. The effective reaction area of the cathode material between the in-situ Raman module and the cathode chamber module is 1 cm 2 .

[0057] In this example, taking the electrochemically reduced carbon dioxide with magnetron-sputtered nano-copper particles on a hydrophobic carbon paper as the catalyst as an example, an in-situ Raman spectroscopy cell for real-time detection of the three-phase interface during the electrochemical reaction is used for in-situ characterization testing. Among them, the ion exchange membrane 11 is selected as an anion exchange membrane of the model Fumasep FAA-3-50, and the cathode material 12 is selected as a conductive hydrophobic carbon paper loaded with nano-copper particles.

[0058] During operation, carbon dioxide gas passes through the gas flow controller and enters the cathode chamber gas cavity and the serpentine flow channel from the cathode chamber gas inlet channel at a flow rate of 20 sccm. Then, a part of the carbon dioxide flows out of the in-situ Raman spectroscopy cell from the cathode chamber gas outlet channel, and another part of the carbon dioxide enters the in-situ Raman module gas chamber through the gas diffusion electrode and then reaches the catalyst surface to participate in the carbon dioxide reduction reaction.

[0059] In this example, 1M KHCO 3 is used as the electrolyte, and the flow rate of the electrolyte is controlled to be 10 ml / min by a peristaltic pump. An in-situ Raman spectrometer equipped with a 10-fold objective lens is used to perform tests at different positions on the catalyst surface. The laser of the in-situ Raman spectrometer operates at a power of 10.2 mW at a wavelength of 633 nm. Raman spectra are recorded in the range of wavenumbers from 0 to 3200 cm -1 , with an exposure time of 1 second each time and an accumulation times of 30 times.

[0060] Taking the electrochemical carbon dioxide reduction reaction as an example, the structural changes and intermediate adsorption conditions on the catalyst surface during the reaction process are observed. The specific process is as follows: The Raman laser emitted by the laser passes through the quartz glass observation window 2 and irradiates on the cathode material 12 loaded with nano-copper particles. The scattered light generated is collected by the Raman spectrometer, and thus the obtained in-situ Raman spectra are analyzed. See Figure 3 .

[0061] As described above, it is only one of the specific implementation cases of the present utility model, and does not impose any formal restrictions on the usage mode of the present utility model. Any simple modification, equivalent change or modification made to the above examples based on the essence of the method of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. An in-situ Raman spectroscopy cell for real-time detection of three-phase interfaces in an electrochemical reaction process, characterized in that: It comprises the following components connected in sequence: an upper cover plate (1), a quartz glass observation window (2), an in-situ Raman module (4), a reference electrode (5), a cathode material (12), a cathode chamber module (7), an anode chamber module (8), a counter electrode (9), an ion exchange membrane (10), and a rubber sealing ring; A quartz glass observation window (2) is provided between the upper cover plate (1) and the in-situ Raman module (4); The reference electrode (5) is fixed on the in-situ Raman module (4) and connected to the electrochemical workstation; A cathode material (12) is provided between the in-situ Raman module (4) and the cathode chamber module (7), and the cathode material (12) is electrically conductive through a copper tape and connected to the cathode of the electrochemical workstation; An ion exchange membrane (10) is provided between the in-situ Raman module (4) and the anode chamber module (8); The counter electrode (9) is fixed on the anode chamber module (8) and connected to the anode of the electrochemical workstation; The adjacent modules are sealed with rubber sealing rings and nuts to achieve gas and electrolyte sealing; In the in-situ Raman module (4), the user can select different cathode test materials to combine them by themselves.

2. The in-situ Raman spectroscopy cell for real-time detection of three-phase interfaces in an electrochemical reaction process according to claim 1, characterized in that: The in-situ Raman module (4) comprises: In-situ Raman module body; The in-situ Raman module gas chamber is disposed at the bottom of the in-situ Raman module body, and the in-situ Raman gas chamber is separated from the cathode chamber module at the bottom by a cathode material; The in-situ Raman module electrolyte cavity is opened in the middle of the in-situ Raman module body, the upper cover plate (1) is located above the in-situ Raman module electrolyte cavity and is separated by a quartz glass observation window (2), and the cathode chamber module (7) is located below the in-situ Raman module electrolyte cavity and is separated by a cathode material (12); An in-situ Raman module electrolyte inlet channel is opened on the side of the in-situ Raman module (4), close to one side of the ion exchange membrane (10), and is connected to the in-situ Raman module electrolyte cavity and the peristaltic pump; The in-situ Raman module electrolyte outlet channel is opened on the side of the in-situ Raman module (4), away from the side of the ion exchange membrane (10), and is connected to the in-situ Raman module electrolyte cavity.

3. The in-situ Raman spectroscopy cell for real-time detection of three-phase interfaces in an electrochemical reaction process according to claim 2, characterized in that: The cathode chamber module (7) comprises: cathode chamber body; The cathode chamber gas cavity and serpentine flow channel are opened at the top of the cathode chamber body, and gas is introduced according to the set reaction conditions and test requirements; The cathode chamber gas inlet channel is opened on the side of the cathode chamber body and is connected to the cathode chamber gas cavity and the gas flow controller; The cathode chamber gas outlet channel is opened on the side of the cathode chamber body and is communicated with the cathode chamber gas cavity.

4. The in-situ Raman spectroscopy cell for real-time detection of three-phase interfaces in an electrochemical reaction process according to claim 3, characterized in that: The anode chamber module (8) comprises: Anode chamber body; The anode chamber electrolyte cavity is opened in the middle of the anode chamber body, the anode chamber electrolyte cavity and the autonomous module electrolyte cavity are separated by an ion exchange membrane, and the anode electrolyte cavity is filled with an anode electrolyte; The anode chamber electrolyte inlet channel is opened at the top of the anode chamber body and is connected with the anode chamber electrolyte cavity and the peristaltic pump; The electrolyte outlet channel of the anode chamber is opened on the side of the anode chamber body and is connected to the electrolyte cavity of the anode chamber. The counter electrode (9) is placed horizontally in the electrolyte cavity of the anode chamber.

Images