Analytical method and analytical system for activity difference of HER and DER of electrolyzed water catalyst

Abstract

The invention relates to a method for analyzing the activity difference of HER and DER of electrolyzed water catalysts. The method comprises the following steps: providing an electrochemical in-situ infrared reaction tank in butt joint with an FTIR instrument light path, and connecting an electrolyte containing H2O or D2O and the electrochemical in-situ infrared reaction tank of a three-electrode system with an electrochemical workstation; applying a scanning potential, and synchronously collecting an in-situ infrared spectrum of the surface of the catalyst to be detected through an FTIR (Fourier Transform Infrared Spectroscopy) instrument; identifying a hydrogen adsorption intermediate characteristic vibration peak related to HER and a deuterium adsorption intermediate characteristic vibration peak related to DER in the in-situ infrared spectrum; and analyzing the activity difference of the to-be-detected catalyst to HER and DER. The invention also relates to an activity analysis system of the deuterium-rich catalyst for hydrogen evolution by electrolysis of water, which is used for realizing the analysis method. By establishing the corresponding relationship between the characteristic vibration peak intensity of the hydrogen / deuterium adsorption intermediate and the scanning potential, the activity difference of the catalyst to be detected on HER and DER can be intuitively and accurately analyzed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the cross field of electrochemical catalysis and isotope separation, and more particularly relates to a method for analyzing the activity difference of a water electrolysis catalyst HER and DER and an analysis system thereof. BACKGROUND

[0002] Electrolysis of deuterium-rich (D2O) technology is a key link in the nuclear industry, pharmaceutical synthesis (such as the preparation of deuterated drugs) and scientific research (such as neutron scattering experiments), and the core challenge lies in the efficient separation of hydrogen (H) and deuterium (D) isotopes. The catalytic activity difference of electrocatalysts for hydrogen evolution reaction (HER, cathodic reaction of water electrolysis H2O to generate hydrogen H2, reaction formula: 2H + + 2e - → H2) and deuterium evolution reaction (DER, cathodic reaction of heavy water D2O to generate deuterium D2, reaction formula: 2D + + 2e - → D2) is a key factor affecting the efficiency and economy of electrolysis of deuterium-rich, so the development of high selectivity deuterium enrichment catalysts has become a core demand in this field.

[0003] However, the current electrolysis of deuterium-rich technology still faces significant scientific and technical bottlenecks, which hinders the development and application of high selectivity deuterium enrichment catalysts.

[0004] First, the isotope effect is difficult to quantify, and the activity difference cannot be directly characterized. Hydrogen and deuterium have significant kinetic isotope effect (KIE) due to the difference in mass, which is manifested in that the dissociation energy barrier of D2O is higher than that of H2O, which in turn leads to the essential difference in the reaction kinetics of HER and DER. However, existing traditional electrochemical characterization methods (such as electrochemical impedance spectroscopy, polarization curve, etc.) can only indirectly infer the activity difference of the catalyst for HER and DER through the apparent current density, and cannot directly identify and distinguish the hydrogen intermediate (H*) and deuterium intermediate (D*) adsorbed on the catalyst surface. This makes it impossible to accurately obtain key reaction parameters such as the adsorption amount and desorption kinetics of H and D related chemical species on the catalyst surface, and the quantitative analysis of the isotope effect lacks direct experimental basis, which seriously hinders the in-depth understanding of the HER / DER reaction mechanism.

[0005] Secondly, the catalyst screening lacks scientific standards and relies on inefficient trial-and-error methods. In existing technologies, the optimization and screening of catalysts mainly rely on empirical trial-and-error methods. For example, for common catalysts such as platinum-ruthenium (Pt-Ru) alloys, researchers can only verify the performance by repeatedly adjusting catalyst components and preparation process parameters, but they cannot determine whether H or D dominates the adsorption on the catalyst surface during the reaction process. This "blind screening" mode not only consumes time and effort, but also makes it difficult to efficiently lock the optimal catalyst formula. Moreover, it may miss potential catalysts with high deuterium selectivity due to the inability to capture key intermediate information, leading to low efficiency in catalyst development.

[0006] Furthermore, the mechanism research tools have limitations and cannot reflect the dynamic reaction process. Conventional surface characterization techniques such as X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) can only provide static surface information (such as elemental composition and microstructure) of the catalyst, and cannot observe the dynamic adsorption of H* / D* in real time under actual electrolysis potential conditions.

[0007] The existing electrochemical mass spectrometry (EC-MS) combined technology principle is to detect the H2 / D2 gas ratio generated during the electrolysis process online, indirectly reflecting the deuterium selectivity of the catalyst. However, this technology can only detect the final reaction products and cannot distinguish between H and D intermediates adsorbed on the catalyst surface. Moreover, it has low sensitivity (requires high concentration of D2O as electrolyte), and the mass spectrometry signal is easily disturbed by the gas bubbles generated during electrolysis, making it difficult to accurately correlate the product with the surface reaction process.

[0008] The existing surface-enhanced Raman spectroscopy (SERS) principle is to detect catalyst surface adsorbed species through enhanced Raman signals, but this technology has insufficient sensitivity to H* / D* characteristic signals, and requires special roughened electrodes (such as gold nanostructure electrodes) to achieve signal enhancement, which has a narrow application range and cannot be widely used in the characterization of conventional catalysts.

[0009] The existing isotope labeling-temperature programmed desorption experiment (TPD) principle is to pre-adsorb H or D on the catalyst, and then measure the desorption peak temperature difference of H2 / D2 through temperature programmed desorption to analyze the adsorption energy. However, this technology is a non-in situ characterization method and cannot reflect the dynamic H* / D* adsorption behavior during electrolysis. Moreover, it is only suitable for ultra-high vacuum experimental conditions, which has a large gap with the actual electrolysis environment, and the characterization results have limited guiding significance for actual catalyst development.

[0010] In summary, the current electrolytic deuterium enrichment technology field urgently needs a technology that can directly and real-time distinguish H* / D* adsorption intermediates with high sensitivity under actual electrolysis conditions, and establish their correlation with HER / DER activity, to break through the bottlenecks of isotope effect quantification difficulty, blind catalyst screening, and insufficient mechanism research tools, and provide scientific support for the development and optimization of high selectivity deuterium enrichment catalysts. SUMMARY

[0011] In order to solve the problems of catalyst screening relying on trial and error in the prior art, the present application aims to provide a method for analyzing the activity difference of HER and DER of an electrolytic water catalyst and an analysis system thereof.

[0012] The method for analyzing the activity difference of HER and DER of an electrolytic water catalyst according to the present application comprises the following steps: S1, providing an electrochemical in-situ infrared reaction cell connected with the light path of an FTIR instrument, the electrochemical in-situ infrared reaction cell containing an electrolyte containing H2O or D2O, the electrochemical in-situ infrared reaction cell being provided with a three-electrode system connected with an electrochemical workstation, the three-electrode system being composed of a working electrode, a reference electrode and a counter electrode, a catalyst to be tested being loaded on the working electrode; S2, applying a scanning potential of 0V to -1.5V vs. RHE to the working electrode through the electrochemical workstation, while synchronously collecting in-situ infrared spectra of the surface of the catalyst to be tested by the FTIR instrument, the collection range of the in-situ infrared spectra being 4000-1000cm-1; S3, taking the infrared spectra collected at the open circuit voltage as the background, identifying the characteristic vibration peaks of hydrogen adsorption intermediates related to HER and the characteristic vibration peaks of deuterium adsorption intermediates related to DER in the in-situ infrared spectra; S4, analyzing the activity difference of the catalyst to be tested for HER and DER according to the corresponding relationship between the peak intensity of the hydrogen adsorption intermediate characteristic vibration peak, the deuterium adsorption intermediate characteristic vibration peak and the scanning potential. -1

[0013] In a preferred embodiment, in the step S1, the preparation method of the working electrode comprises: S11, mixing 4-6mg of catalyst powder to be tested, 900-950μL of solvent and 75-85μL of 5% mass fraction naphthol binder, and ultrasonic treatment for 12-18min to obtain catalyst slurry; S12, taking 18-22μL of the catalyst slurry and dropping it on the surface of a conductive substrate with a diameter of 4-6mm, and standing in the air for 12-18min for drying to obtain the working electrode.

[0014] In a preferred embodiment, the catalyst to be tested is a carbon-supported metal catalyst, including Pt / C or Ru / C catalyst; the solvent is ethanol, isopropanol or water; and the conductive substrate is a glassy carbon electrode, a gold disc electrode or a platinum disc electrode.

[0015] In a preferred embodiment, the electrolyte further comprises potassium sulfate with a concentration of 0.4-0.6mol / L.

[0016] ​In a preferred embodiment, in the step S2, the scanning potential is applied in the form of LSV, the scanning rate is 1.5-2.5 mV / s, and the in-situ FTIR spectrum is collected every 25-35 mV.

[0017] In a preferred embodiment, in the step S2, the FTIR instrument collects the in-situ FTIR spectrum with the following parameters: resolution 3-5 cm -1 , and scanning times 28-36.

[0018] In a preferred embodiment, in the step S3, the wave number range of the characteristic vibration peak of the hydrogen adsorption intermediate is 3800-3400 cm -1 , including the stretching vibration peak of Pt-OH and Ru-OH; and the wave number range of the characteristic vibration peak of the deuterium adsorption intermediate is 2000-1800 cm -1 , including the bending vibration peak of Pt-D and Ru-D.

[0019] In a preferred embodiment, the reference electrode is Ag / AgCl, and the counter electrode is a platinum wire.

[0020] The electrolytic water hydrogen evolution deuterium-rich catalyst activity analysis system for realizing the analysis method according to the above is used to realize the analysis method according to the above, and includes an FTIR instrument, an ER-IRAS electrochemical in-situ test assembly, and an electrochemical workstation, wherein the ER-IRAS electrochemical in-situ test assembly includes an electrochemical in-situ infrared reaction cell, a three-electrode system, and a window sheet sealingly installed at a light path opening of the electrochemical in-situ infrared reaction cell.

[0021] In a preferred embodiment, the window sheet is a CaF2 window sheet.

[0022] The analysis method according to the present application is characterized in that, by coordinating the use of the three-electrode system loaded with the to-be-tested catalyst, the electrochemical workstation, and the FTIR instrument, the in-situ FTIR spectrum of the surface of the to-be-tested catalyst is collected synchronously in the electrolysis process of applying a scanning potential of 0 V to -1.5 V vs. RHE to the working electrode, and the wave number range is 4000-1000 cm -1The in-situ infrared spectrum in the range is obtained, and the hydrogen adsorption intermediate characteristic vibration peak related to HER and the deuterium adsorption intermediate characteristic vibration peak related to DER are accurately identified based on the infrared spectrum at the open circuit voltage, so that the problems that the prior art cannot directly distinguish the H* / D* adsorption intermediate in-situ, the HER / DER activity difference is difficult to quantify, and the catalyst screening relies on trial and error are effectively solved. By establishing the corresponding relationship between the hydrogen / deuterium adsorption intermediate characteristic vibration peak intensity and the scanning potential, the activity difference of the to-be-tested catalyst for HER and DER can be intuitively and accurately analyzed, which not only provides direct experimental basis for the mechanism research of water electrolysis hydrogen production and deuterium enrichment reaction, but also can quickly evaluate the deuterium enrichment selectivity of the catalyst, and further provide reliable technical support for the development and optimization of the high-selectivity deuterium enrichment catalyst and the accurate regulation of the deuterium electrolysis enrichment process. Compared with the existing EC-MS technology which can only detect H2 / D2 products, the present application realizes the breakthrough from "product analysis" to "intermediate dynamic monitoring" by identifying the H* / D* intermediate characteristic peak, and solves the problem that the intermediate cannot be distinguished in the background technology. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structural schematic diagram of an electrolysis water hydrogen production and deuterium enrichment catalyst activity analysis system of an electrochemical in-situ ER-IRAS according to a preferred embodiment of the present application.

[0024] Figure 2 is an electrochemical in-situ infrared spectrum diagram of a Pt electrode in an H2O electrolyte.

[0025] Figure 3 is an electrochemical in-situ infrared spectrum diagram of a Ru electrode in an H2O electrolyte.

[0026] Figure 4 is an electrochemical in-situ infrared spectrum diagram of a Pt electrode in a heavy water electrolyte (0 to-0.9V vs. RHE).

[0027] Figure 5 is an electrochemical in-situ infrared spectrum diagram of a Pt electrode in a heavy water electrolyte (-0.9 to-1.5V vs. RHE).

[0028] Figure 6 is an electrochemical in-situ infrared spectrum diagram of a Ru electrode in a heavy water electrolyte (0 to-0.9V vs. RHE).

[0029] Figure 7 is an electrochemical in-situ infrared spectrum diagram of a Ru electrode in a heavy water electrolyte (-0.9 to-1.5V vs. RHE). DETAILED DESCRIPTION

[0030] The preferred embodiments of the present application will be described below in detail with reference to the accompanying drawings.

[0031] The application provides an electrolytic water hydrogen evolution deuterium-rich catalyst activity analysis system based on electrochemical in-situ external reflection infrared absorption spectroscopy (ER-IRAS). The system realizes in-situ dynamic monitoring of H* / D* adsorption intermediates, and further analyzes the activity difference of the catalyst for HER / DER. The following will be described in combination with Figure 1 The overall assembly relationship, function and connection mode of each component of the system are described in detail.

[0032] The catalyst activity analysis system according to the application is an electrochemistry-infrared spectrum combined system, which comprises a Fourier Transform Infrared Spectroscopy (FTIR instrument 1), an ER-IRAS electrochemical in-situ test assembly 2 and an electrochemical workstation 3.

[0033] The ER-IRAS electrochemical in-situ test assembly 2 comprises an electrochemical in-situ infrared reaction cell 21. The electrochemical in-situ infrared reaction cell 21 is a core reaction container in a closed cavity structure, is located between the FTIR instrument 1 and the electrochemical workstation 3, and the infrared light path and the electrochemical circuit both need to penetrate the cavity. The electrochemical in-situ infrared reaction cell 21 is made of polyether ether ketone (PEEK) and has the characteristics of high temperature resistance and strong acid and alkali corrosion resistance, which is suitable for the harsh environment of electrolytic deuterium enrichment experiments. The electrochemical in-situ infrared reaction cell 21 provides a closed reaction space, contains electrolyte inside, avoids evaporation and pollution of the electrolyte by external impurities. In a preferred embodiment, the electrolyte is light water / heavy water plus 0.5 mol / L potassium sulfate.

[0034] The ER-IRAS electrochemical in-situ testing assembly 2 further comprises an electrode system 22. The electrode system 22 is a three-electrode system, comprising a working electrode (WE), a reference electrode (RE) and a counter electrode (CE) vertically inserted into the electrolyte in the electrochemical in-situ infrared reaction cell. The cavity of the electrochemical in-situ infrared reaction cell 21 is pre-provided with three electrode interfaces, and the WE, RE and CE are respectively inserted into the corresponding interfaces for fixation. The bottom of the WE, RE and CE is immersed below the liquid level of the electrolyte, and the top is connected to the electrochemical workstation 3 through a wire to form a complete electrochemical testing loop for applying a scanning potential and collecting electrochemical reaction signals. The working electrode is composed of an electrode substrate (a conductive material providing mechanical support and current conduction) and a catalyst slurry (an electrode active material responsible for catalyzing the HER / DER reaction) loaded on the surface of the substrate, which is the electrochemical reaction occurrence area and the infrared signal observation target. The electrode substrate is a carbon material or a metal material, such as a glassy carbon, a gold disc or a platinum disc. The catalyst slurry is a mixture of the catalyst to be tested (such as Pt / C, Ru / C) and a binder and a solvent. During the test, electrochemical reactions occur on the surface of the electrode material, and the chemical structure, functional groups and other information of the surface chemical species can be tested and analyzed by in-situ infrared spectroscopy. In a preferred embodiment, the WE is a glassy carbon electrode. In a preferred embodiment, 5 mg of catalyst powder to be tested (such as Pt / C, Ru / C, etc.), 920 μL of ethanol (or isopropanol or water) and 80 μL of 5% naphthol (binder) are mixed to prepare a catalyst slurry by ultrasonic treatment for 15 min. 20 μL of the slurry is dropped on the surface of a glassy carbon electrode with a diameter of 5 mm, and the working electrode is obtained after drying in air for 15 min. The reference electrode provides a stable potential reference point to ensure the accuracy of the electrochemical test potential. In a preferred embodiment, the RE is a silver-silver chloride electrode (Ag / AgCl). The counter electrode forms a current loop to conduct the current between the working electrode and the power supply. In a preferred embodiment, the CE is a platinum wire (0.5 mm in diameter and 5 cm in length).

[0035] The ER-IRAS electrochemical in-situ testing assembly 2 further comprises a window sheet 23 sealingly installed at the light path opening of the electrochemical in-situ infrared reaction cell 21. The window sheet 23 serves as a "transmission window" for infrared light, allowing the interference beam of the FTIR instrument 1 to penetrate the window sheet 23 into the electrochemical in-situ infrared reaction cell 21, while allowing the infrared signal reflected by the working electrode to penetrate out. In addition, the window sheet 23 can also isolate the electrolyte from the external environment, prevent the working electrode (such as a surface gold film) from being corroded, and avoid solvent evaporation or bubbles entering the light path to affect the signal stability. In a preferred embodiment, the window sheet 23 is a CaF2 window sheet, which has a transmittance of ≥90% in the infrared waveband of 4000-800 cm -1 -1, and is chemically inert.

[0036] The ER-IRAS electrochemical in-situ testing assembly 2 further comprises a liquid / gas inlet 24 and a liquid / gas outlet 25 arranged on the sidewall of the electrochemical in-situ infrared reaction cell 21, for injection and discharge of electrolyte or gas. The type and concentration of the injected electrolyte or the type of the injected gas can be adjusted according to specific testing requirements. In the present embodiment, no flow injection is required, and thus the injection is closed.

[0037] The FTIR instrument 1 is arranged coaxially with the window sheet 23 on the light path input and output side of the electrochemical in-situ infrared reaction cell 21, and comprises an infrared light source, an interferometer, and a signal detection module (mercury cadmium telluride detector MCT). The infrared light source emits infrared light with a wavelength range of 4000-1000 cm -1 . The interferometer obtains infrared interference light beams through beam splitting and interference processing. The signal detection module receives the infrared signal reflected by the working electrode, converts the optical signal into an electrical signal, and generates an infrared spectrum. The resolution of the FTIR instrument 1 is 4 cm -1 , and the scanning number is 32 scans.

[0038] The electrochemical workstation 3 is a Chenhua 1140 type electrochemical workstation, and can also be replaced by other workstations with linear sweep voltammetry (LSV) function. The electrochemical workstation 3 is connected to the electrode system 22 through a wire, applies a set of electrochemical reaction parameters (such as a voltage range of 0- -1.5 V vs. RHE and a scanning speed of 2 mV / s) to the electrode system 22, collects the current signal of the working electrode, and synchronously sends a trigger signal to the FTIR instrument 1, so as to realize the synchronization of "potential scanning-infrared spectrum acquisition".

[0039] In this way, the infrared interference light beams of the FTIR instrument 1 pass through the light path channel of the ER-IRAS electrochemical in-situ testing assembly 2 in turn, penetrate the window sheet 23, and irradiate the electrode material on the surface of the working electrode. The infrared light reflected by the electrode substrate of the working electrode carries the infrared information of the H* / D* intermediate adsorbed on the surface of the catalyst to be tested, penetrates the window sheet 23 again, and returns to the signal detection module of the FTIR instrument 1.

[0040] In the prior art, the EC-MS and SERS combined systems have the problems of "non-in-situ" and "signal lag". The FTIR instrument 1, the ER-IRAS electrochemical in-situ testing assembly 2, and the electrochemical workstation 3 are deeply integrated in the present application, and the synchronous trigger control of the electrochemical workstation and the FTIR instrument not only realizes the synchronous acquisition of infrared spectra at every 30 mV potential interval in the voltage range of 0- -1.5 V vs. RHE, but also directly distinguishes the vibration signals of the H* / D* adsorption intermediate (such as the H-related peak 3800-3400 cm -1, D related peak 2000~1800cm -1 ), and the direct correlation between the intermediate content and the HER / DER activity is clear.

[0041] The core of the present application is the dynamic monitoring technology of electrochemical in-situ infrared spectroscopy (EC-IR), specifically referring to: in the process of applying electrolytic potential to the working electrode, through the combination of ER-IRAS accessory and FTIR instrument, the infrared vibration signals of the HER / DER reaction intermediates (such as H derived Pt-OH, directly adsorbed D, i.e. Pt-D) adsorbed on the catalyst surface are collected in real time, the dynamic tracking of the intermediate molecular characteristics is realized, which is significantly different from the traditional non-in-situ characterization, and the intermediate change can be directly captured in the actual electrolysis environment (liquid phase, power-on state), which provides direct experimental basis for activity difference analysis.

[0042] Example 1

[0043] The Pt / C and Ru / C catalysts were tested in light water (H2O) and heavy water (D2O) electrolyte, wherein the electrochemical parameters were LSV method, voltage range 0~ -1.5V vs. RHE, scan rate 2mV / s; the infrared parameters were resolution 4cm -1 , scan times 32 times, spectral range 4000~1000cm -1 .

[0044] Figure 2 The electrochemical in-situ infrared spectra of Pt catalyst in H2O electrolyte obtained by scanning at 30mV intervals from 0V to -1.5V vs. RHE are shown. The core characteristic peaks and their analysis are as follows:

[0045] 3488cm -1 : hydrogen-bonded adsorbed *OH stretching (Pt-OH···H2O), reflecting the strong hydrogen bond network between interfacial water molecules, the strength increases with the negative shift of potential, and then decreases (H2 is quickly formed and falls off);

[0046] 2918 / 2845cm -1 : may be the collective vibration of the interfacial water hydrogen bond network;

[0047] 2640cm -1 : strong hydrogen-bonded Pt-OH stretching vibration (Pt-OH···H2O);

[0048] 1867cm -1 : interfacial hydrated proton (H5O2 + or H3O+ deformation vibration);

[0049] 1646cm-1 : Standard H2O bending vibration (delta-HOH), if intensity varies with potential, it indicates interfacial water reorganization;

[0050] 1500 cm -1 : Collective vibration of interfacial water hydrogen bond network (independent of H / D);

[0051] 1238 cm -1 : Hydrogen-bonded adsorbed *OH - Bending vibration (Pt-OH).

[0052] Figure 3 Electrochemical in-situ infrared spectra of Ru catalyst in H2O electrolyte, obtained by scanning from 0 V to -1.5 V vs. RHE at 30 mV intervals, are shown. The core characteristic peaks and their analysis are as follows:

[0053] 3705 cm -1 : Adsorbed *OH stretching vibration (Ru-OH);

[0054] 3273 cm -1 : Coordinated H2O (Ru-H2O);

[0055] 2111 cm -1 : Interfacial water proton (H5O2 + or H3O + deformation vibration);

[0056] 1747 cm -1 : Adsorbed water H2O bending vibration (Ru-H2O);

[0057] 1632 cm -1 : Adsorbed water H2O bending vibration (Ru-H2O).

[0058] Comparison Figure 2 and Figure 3 It can be found that the characteristic peaks of the spectrum of Ru catalyst in H2O electrolyte are relatively weak, indicating that the performance of Ru metal catalyst for HER is poor.

[0059] Figure 4 Electrochemical in-situ infrared spectra of Pt catalyst in heavy water electrolyte, obtained by scanning from 0 V to -0.9 V vs. RHE at 30 mV intervals, are shown. The core characteristic peaks and their analysis are as follows:

[0060] 3664 cm -1 : Adsorbed *OH stretching vibration (Pt-OH);

[0061] 3109 cm -1 : Coordinated H2O (Pt-H2O);

[0062] 2918 / 2845 cm -1 : collective vibration of interfacial water hydrogen bond network;

[0063] 2628 cm -1 : D20 stretching vibration;

[0064] 2514 cm -1 : HDO stretching vibration;

[0065] 1939 cm -1 : bending vibration of Pt-D*;

[0066] 1646 cm -1 : bending vibration of adsorbed water H20 (Pt-H20);

[0067] 1576 / 1541 cm -1 : collective vibration of interfacial water hydrogen bond network (independent of H / D);

[0068] 1375 cm -1 : stretching vibration of adsorbed *D (Pt-D).

[0069] 1210 cm -1 : bending vibration of adsorbed *OD - (Pt-OD).

[0070] Figure 5 The electrochemical in-situ FTIR spectra of Pt catalyst in D20 electrolyte were obtained by scanning from -0.9 V to -1.5 V vs. RHE at 30 mV intervals. At high potentials, no new surface chemical species were added on the Pt catalyst, but several peaks were weakened or even disappeared, including 3664 cm -1 , 3109 cm -1 , 2918 / 2845 cm -1 , 1576 / 1541 cm -1 characteristic peaks of several H-containing intermediates, but the 1939 cm -1 (Pt-D* bending vibration) peak did not change much.

[0071] Comparing Figure 4 and Figure 5 , it can be found that in the D20 electrolyte containing trace H20 (mass fraction of H20 is less than 5%), the Pt catalyst can still catalyze the HER reaction at low voltage, but when the voltage rises, the DER reaction will dominate, indicating that the working voltage of the Pt catalyst for hydrogen evolution with deuterium enrichment cannot be too high.

[0072] Figure 6Electrochemical in-situ FTIR spectra of Ru catalyst in D2O electrolyte from 0 V to -0.9 V vs. RHE with 30 mV interval are shown. The characteristic peaks of Ru in D2O are more obvious than that of HER. The core characteristic peaks and their analysis are as follows:

[0073] 2514 cm -1 : HDO stretching vibration;

[0074] 1897 cm -1 : bending vibration of Ru-D*;

[0075] 1359 cm -1 : collective vibration of interface water hydrogen bond network;

[0076] 1210 cm -1 : adsorbed OD- bending vibration (Ru-OD).

[0077] Figure 7 Electrochemical in-situ FTIR spectra of Ru catalyst in D2O electrolyte from -0.9 V to -1.5 V vs. RHE with 30 mV interval are shown. The performance of Ru catalyst in D2O is obviously different from that of Pt metal, and there are many new characteristic peaks in the high and low voltage ranges. The core characteristic peaks and their analysis are as follows:

[0078] 3843 cm -1 : adsorbed OH stretching vibration (Ru-OH);

[0079] 3431 cm -1 : hydrogen-bonded adsorbed OH stretching (Ru-OH···H2O);

[0080] 2949 cm -1 : coordinated H2O (Ru-H2O);

[0081] 2744 cm -1 : strong hydrogen-bonded Ru-OH stretching vibration (Ru-OH···H2O);

[0082] 2514 cm -1 : HDO stretching vibration;

[0083] 2149 cm -1 : asymmetric stretching of adsorbed D3O + (Ru-OD3 + );

[0084] 1897 cm -1 : bending vibration of Ru-D*;

[0085] 1626 cm-1 : adsorbed H2O bending vibration (Ru-H2O);

[0086] 1467 cm -1 : adsorbed *D bending vibration (Ru-D);

[0087] 1359 cm -1 : adsorbed *D stretching vibration (Ru-D);

[0088] 1273 cm -1 : adsorbed *OD - or *D3O + deformation vibration (Ru-OD - or D3O + );

[0089] 1210 cm -1 : adsorbed *OD - bending vibration (Ru-OD);

[0090] 1176 cm -1 : adsorbed *OD-bending vibration (Ru-OD).

[0091] Comparative Figure 6 and Figure 7 It can be found that in the heavy water electrolyte containing trace H2O, the Ru catalyst can hardly catalyze the HER reaction at low voltage, but when the voltage is increased, the characteristic peaks of H-containing intermediates (3843 cm -1 , 3431 cm -1 , 2949 cm -1 , 2744 cm -1 , 1626 cm -1 ) appear, and the Ru catalytic HER reaction is very obvious, even better than the Pt catalyst, the characteristic peaks of part of D-containing intermediates (1897 cm -1 , 1359 cm -1 , 1210 cm -1 ) disappear, and new characteristic peaks of D-containing intermediates (2149 cm -1 , 1467 cm -1 , 1273 cm -1 , 1176 cm -1 ) appear, which may be due to the change of the adsorption form of the intermediates. This shows that the Ru catalyst has high deuterium enrichment ability for hydrogen evolution at high voltage. However, at high voltage, HER and DER exist simultaneously, and the selectivity of hydrogen evolution is limited.

[0092] The present application analyzes the surface chemical species of platinum carbon (Pt / C) catalyst or ruthenium carbon (Ru / C) catalyst under negative potential in light water / heavy water by electrochemical in-situ infrared spectroscopy technology, finds the influence of voltage and metal component on HER and DER, and proves the feasibility of the technology for screening or optimizing efficient hydrogen evolution deuterium enrichment catalyst. Specifically, in the heavy water electrolyte containing trace amount of H2O, at low voltage (0 to-0.9V vs. RHE), the Ru catalyst almost cannot catalyze the HER reaction, but when the voltage is increased (-0.9 to-1.5V vs. RHE), the Ru catalyzed HER reaction is very obvious, and even better than the Pt catalyst; at low voltage, the Pt catalyst can still catalyze the HER reaction, but when the voltage is increased, the DER reaction will dominate, verifying the effectiveness of the system for analyzing the activity of the catalyst.

[0093] Based on the above experimental verification, the EC-IR online monitoring function (containing CaF2 window piece and FTIR signal acquisition module) of the system can be integrated into an industrial deuterium enrichment electrolytic tank, the characteristic peaks of H* / D* intermediates on the surface of the catalyst are collected in real time, the working potential of the electrolytic tank is dynamically adjusted (such as the Pt-based electrolytic tank is controlled at-0.9 to-1.5V vs. RHE to strengthen DER, and the Ru-based electrolytic tank is selected at low voltage (0 to-0.9V vs. RHE) to inhibit HER according to requirements), and the real-time optimization of deuterium enrichment efficiency is realized. Moreover, the present application can replace the traditional trial-and-error method for screening deuterium enrichment catalysts. For the Pd / C, Ir / C and other catalysts to be screened, without repeated adjustment of the preparation process, only the H* / D* peak intensity ratio in light water / heavy water of the catalyst needs to be tested (such as when the D characteristic peak intensity / H characteristic peak intensity is greater than or equal to 1.2, it is determined as a high DER selectivity catalyst), the selectivity evaluation of a single catalyst is quickly completed, and the screening period is greatly shortened. Further, the present application can capture the H* / D* peak changes at different electrolysis times through real-time monitoring by EC-IR. For example, in the Pt-based electrolytic tank operation, if the H-related peak intensity at 3800 to 3400cm -1 is found to rise, it indicates that the H2O content in the electrolyte increases, and D2O needs to be supplemented in time; if the D-related peak intensity at 2000 to 1800cm -1 decreases, the DER activity can be restored by fine adjustment of the working potential, avoiding the deuterium loss caused by the 'empirical adjustment' of the traditional process.

[0094] The above is only a preferred embodiment of the present application, and is not intended to limit the scope of the present application. The above embodiment of the present application can be variously changed. Any simple, equivalent changes and modifications made in accordance with the content of the claims and description of the present application fall within the scope of the claims of the present application. The present application is not described in detail.

Claims

1. A method for analyzing the difference in HER and DER activity of an electrolytic water catalyst, characterized by, The analysis method comprises the following steps: S1, providing an electrochemical in-situ infrared reaction cell connected with the light path of an FTIR instrument, the electrochemical in-situ infrared reaction cell containing an electrolyte containing H2O or D2O, the electrochemical in-situ infrared reaction cell being provided with a three-electrode system connected with an electrochemical workstation, the three-electrode system being composed of a working electrode, a reference electrode and a counter electrode, a catalyst to be measured being loaded on the working electrode; S2, applying a scanning potential of 0 V to -1.5 V vs. RHE to the working electrode by the electrochemical work station, while synchronously collecting in-situ infrared spectrum of the surface of the catalyst to be tested by the FTIR instrument, the collection range of the in-situ infrared spectrum being 4000-1000 cm -1 ; S3, identifying the characteristic vibration peaks of hydrogen adsorption intermediates related to HER and the characteristic vibration peaks of deuterium adsorption intermediates related to DER in the in-situ infrared spectrum based on the infrared spectrum collected at the open circuit voltage as the background; S4, analyzing the activity difference of the catalyst to be measured for HER and DER according to the corresponding relationship between the peak intensity of the hydrogen adsorption intermediate characteristic vibration peak, the deuterium adsorption intermediate characteristic vibration peak and the scanning potential.

2. The resolution method according to claim 1, wherein, In the step S1, the preparation method of the working electrode comprises: S11, mixing 4-6 mg of catalyst powder to be measured, 900-950 μL of solvent and 75-85 μL of 5% mass fraction naphthol binder, and ultrasonic treatment for 12-18 min to obtain catalyst slurry; S12, taking 18-22 μL of the catalyst slurry and dropping it on the surface of a conductive substrate with a diameter of 4-6 mm, and standing in the air for 12-18 min to dry, to obtain the working electrode.

3. The resolution method according to claim 2, wherein, The catalyst to be measured is a carbon-supported metal catalyst, including Pt / C or Ru / C catalyst; the solvent is ethanol, isopropyl alcohol or water; and the conductive substrate is a glassy carbon electrode, a gold disc electrode or a platinum disc electrode.

4. The resolution method according to claim 1, wherein, The electrolyte further comprises potassium sulfate with a concentration of 0.4-0.6 mol / L.

5. The resolution method according to claim 1, wherein, In the step S2, the scanning potential is applied in the form of LSV, the scanning rate is 1.5-2.5 mV / s, and the in-situ infrared spectrum is collected every 25-35 mV.

6. The resolution method of claim 1, wherein, In the step S2, the FTIR instrument collects the in-situ infrared spectrum with the parameters of resolution 3-5 cm -1 , scanning times 28-36 times.

7. The resolution method according to claim 1, wherein, In the step S3, the wave number range of the characteristic vibration peak of the hydrogen adsorption intermediate is 3800-3400 cm -1 , including the stretching vibration peak of Pt-OH, Ru-OH; the wave number range of the characteristic vibration peak of the deuterium adsorption intermediate is 2000-1800 cm -1 , including the bending vibration peak of Pt-D, Ru-D.

8. The resolution method according to claim 1, wherein, The reference electrode is Ag / AgCl, and the counter electrode is a platinum wire.

9. A system for electrolytic water dissociation hydrogen-deuterium catalyst activity analysis for implementing the resolution method according to any one of claims 1-8, comprising an FTIR instrument, an ER-IRAS electrochemical in-situ test assembly and an electrochemical work station, wherein, The ER-IRAS electrochemical in-situ test assembly comprises an electrochemical in-situ infrared reaction cell, a three-electrode system and a window sheet sealed and installed at the light path opening of the electrochemical in-situ infrared reaction cell.

10. The water electrolysis hydrogen evolution deuterium-rich catalyst activity analysis system according to claim 9, wherein, The window sheet is a CaF2 window sheet.

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