Method for testing electrocatalytic performance of transition metal oxide thin film

Abstract

The application is suitable for the technical field of electrochemical performance test, and provides a method for testing the electrocatalytic performance of a transition metal oxide film. The method comprises the steps of film sample pretreatment, test electrolyte preparation, electrochemical test system building, electrochemical test parameter setting, and test data processing and analysis. The application optimizes the key parameters and process design related to the test according to the characteristics of the transition metal oxide film, and realizes comprehensive and accurate evaluation of the electrocatalytic performance of the film. The test method has high standardization, clear operation process and good repeatability, and the test result is accurate and reliable and has good comparability. The application can provide a unified evaluation standard for the electrocatalytic performance of the transition metal oxide film for different research institutions, and provide a reliable basis for the performance evaluation and application research of the film, which is conducive to promoting the application research of the film in the field of new energy.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical performance testing technology, and particularly relates to a method for testing the electrocatalytic performance of transition metal oxide thin films. Background Technology

[0002] The oxygen evolution reaction (OER) is a key half-reaction in energy conversion and storage technologies such as water splitting, metal-air batteries, and rechargeable fuel cells. Due to its slow four-electron transfer kinetics, developing efficient, stable, and cost-effective OER catalysts is crucial.

[0003] Perovskite oxides (ABO3) have become promising non-noble metal OER catalysts due to their tunable composition, stable structure, and intrinsically high activity. Among them, La... x Ni 0.5 Fe 0.5 O3, as a double B-site perovskite, is expected to achieve excellent OER catalytic activity through the synergistic effect between Ni and Fe.

[0004] However, unlike powdered catalysts, thin-film La x Ni 0.5 Fe 0.5 O3 faces unique challenges in testing. Currently, testing methods for the OER catalytic performance of powdered catalysts are relatively mature, typically employing a drop-coating method to load the powdered catalyst onto substrates such as glassy carbon electrodes. However, existing methods for testing the OER catalytic performance of thin-film catalysts suffer from problems such as mismatched testing systems, non-standardized testing parameters, and the influence of electrode preparation processes on test results. This leads to a lack of comparability of test results from different research institutions, making it difficult to accurately evaluate and optimize the catalytic performance of thin-film catalysts.

[0005] Therefore, develop a method for La x Ni 0.5 Fe 0.5 Testing methods for transition metal oxide thin-film catalysts, such as O3 thin-film catalysts, can accurately, reliably, and repeatedly evaluate their OER catalytic activity, stability, and reaction kinetics, which is of great significance for advancing the research and practical application of such materials. Based on this, this invention proposes a method for testing the electrocatalytic performance of transition metal oxide thin films. Summary of the Invention

[0006] The purpose of this invention is to provide a method for testing the electrocatalytic performance of transition metal oxide thin films, aiming to solve the problems mentioned in the background art.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for testing the electrocatalytic performance of transition metal oxide thin films includes the following steps:

[0009] Step 1: Thin film sample pretreatment;

[0010] A transition metal oxide thin film sample was selected and pretreated. The pretreated transition metal oxide thin film sample was fixed with a stainless steel electrode clamp so that the surface of the transition metal oxide thin film sample was in close contact with the stainless steel surface of the electrode clamp to obtain the working electrode.

[0011] Step 2: Preparation of the test electrolyte; the test electrolyte is an alkaline electrolyte;

[0012] Step 3: Construction of the electrochemical testing system;

[0013] A three-electrode testing system is adopted, including a counter electrode, a reference electrode, and a working electrode. A platinum sheet is used as the counter electrode, and a saturated calomel electrode (SCE), a mercury / mercuric oxide (Hg / HgO) electrode, or a silver / silver chloride (Ag / AgCl) electrode is used as the reference electrode. The working electrode, counter electrode, and reference electrode are inserted into an alkaline electrolyte, ensuring that the electrodes are in full contact with the alkaline electrolyte while remaining in contact with each other.

[0014] Step 4: Setting electrochemical test parameters;

[0015] Turn on the electrochemical workstation and set the test system to a preset stabilization time before testing; perform cyclic voltammetry and linear scan voltammetry in sequence to activate the transition metal oxide film sample and obtain the electrocatalytic oxygen evolution reaction activity data of the transition metal oxide film sample;

[0016] Step 5: Test data processing and analysis;

[0017] The reference electrode voltage data obtained during the test were converted into a potential relative to the reversible hydrogen electrode (RHE), and curve fitting and data analysis were performed to evaluate the electrocatalytic activity of the transition metal oxide thin film samples.

[0018] Furthermore, in step 1, the substrate (i.e., the conductive substrate) of the transition metal oxide thin film sample is LaSrAlTaO3, and the transition metal oxide thin film sample is La x Ni 0.5 Fe 0.5 O3 thin film sample, where x is the amount of A-site vacancy defect, taking a value of 1.0 or 0.9; when x=1.0, LaNi 0.5 Fe 0.5 The effective working area of ​​the O3 thin film sample is 0.0435 cm². 2 When x=0.9, La 0.9 Ni 0.5 Fe 0.5The effective working area of ​​the O3 thin film sample is 0.0575 cm². 2 .

[0019] Furthermore, in step 1, the pretreatment includes: cutting the transition metal oxide thin film sample into a preset size, wiping the surface with anhydrous ethanol and drying at room temperature for 3-5 minutes.

[0020] Furthermore, in step 2, the alkaline electrolyte is one or a mixture of KOH solution, NaOH solution or LiOH solution, and the electrolyte concentration is 0.1~10 mol / L.

[0021] Furthermore, the alkaline electrolyte is a KOH solution with a concentration of 1 mol / L.

[0022] Furthermore, in step 3, the working electrode immerses only the preset effective working area of ​​the transition metal oxide film sample into the alkaline electrolyte, and the transition metal oxide film sample faces the platinum sheet.

[0023] Furthermore, in step 3, the reference electrode is a mercury / mercury oxide electrode.

[0024] Furthermore, in step 4:

[0025] The electrochemical test was a test of the electrocatalytic oxygen evolution reaction;

[0026] The preset time is 10~30 minutes;

[0027] The conditions for cyclic voltammetry testing include: a scan voltage range of -0.5 to -0.4 V (vs. Hg / HgO), a scan rate of 5 to 100 mV / s, and 3 to 10 cycles until the CV curve stabilizes;

[0028] The conditions for linear scanning voltammetry include: a scanning voltage range of 0 ~ 2 V (vs. Hg / HgO) and a scanning rate of 1 ~ 10 mV / s.

[0029] Furthermore, in step 4:

[0030] The conditions for cyclic voltammetry testing include: a scan voltage range of -0.45 ~ -0.35 V (vs. Hg / HgO), a scan rate of 5 mV / s, and 3 cycles.

[0031] The conditions for linear scan voltammetry testing include: a scan voltage range of 0 ~ 2 V (vs. Hg / HgO) and a scan rate of 5 mV / s.

[0032] Furthermore, in step 5, the conversion formula is: E RHE = E Hg / HgO+ 0.098 V + 0.059 × pH; Curve fitting and data analysis were performed using Origin software. The Tafel slope was obtained from the linear sweep voltammetry curve to evaluate the reaction kinetics, and then the electrocatalytic oxygen evolution reaction activity of the transition metal oxide thin film sample was evaluated.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] This invention optimizes key testing parameters and process design for transition metal oxide thin films, taking into account their unique characteristics. Standardized sample pretreatment avoids interference from non-working areas, ensuring test accuracy. An electrochemical testing system, coupled with standardized testing parameters and precise data processing methods, enables a comprehensive evaluation of the electrocatalytic performance of transition metal oxide thin films. The testing method of this invention features high standardization, clear operation procedures, and good repeatability, effectively solving the problems of large result deviations and poor repeatability commonly found in existing testing methods. The test results are accurate, reliable, and highly comparable, providing a unified standard for evaluating the electrocatalytic performance of transition metal oxide thin films for different research institutions. It also provides a reliable basis for the performance evaluation and application research of this type of film, facilitating its application research in the new energy field and possessing significant practical application value and promising prospects. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the three-electrode testing system used in this invention.

[0036] Figure 2 LaNi in Example 1 0.5 Fe 0.5 LSV curves for OER catalytic performance testing of O3 thin films.

[0037] Figure 3 LaNi in Example 1 0.5 Fe 0.5 Tafel slope obtained from the LSV curve of O3 thin film.

[0038] Figure 4 For example, La in Example 2 0.9 Ni 0.5 Fe 0.5 LSV curves for OER catalytic performance testing of O3 thin films.

[0039] Figure 5 For example, La in Example 2 0.9 Ni 0.5 Fe 0.5 Tafel slope obtained from the LSV curve of O3 thin film.

[0040] Figure 6For LaNi 0.5 Fe 0.5 O3 thin film and La 0.9 Ni 0.5 Fe 0.5 Comparison of current densities of O3 thin films at an overpotential of 1.63 V. Detailed Implementation

[0041] To provide a clearer understanding of the technical features, objectives, and beneficial effects of this invention, the technical solution of this invention is described in detail below, but this should not be construed as limiting the scope of implementation of this invention. Unless otherwise specified, the methods used in this invention are conventional methods in this technical field. In this invention, materials, reagents, or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0042] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0043] Example 1;

[0044] A LaNi 0.5 Fe 0.5 The method for testing the OER catalytic performance of O3 thin film samples includes the following steps:

[0045] 1. Thin film sample pretreatment;

[0046] A-site defect-free LaNi was prepared by pulsed laser deposition. 0.5 Fe 0.5 O3 thin film samples: A lanthanum-nickel-iron-oxygen target (stoichiometric ratio of lanthanum, nickel, iron, and oxygen atoms was x:0.5:0.5:3, where x represents the A-site vacancy amount, with a value of 1.0) was used. The substrate was LaSrAlTaO3 (both the substrate and target were purchased from Hefei Single Crystal Materials Technology Co., Ltd.). The growth temperature was set at 700 ℃, the oxygen pressure at 100 mTorr, and the growth time at 1 hour. The repetition frequency of the pulsed laser was set at 2 Hz, and the energy density of the pulsed laser focused on the target was 1.23 J / cm². 2 .

[0047] The obtained thin film sample was cut into pieces approximately 0.25 x 0.25 cm. 2 Size (effective working area is 0.0435 cm²) 2 The film sample surface was gently wiped with anhydrous ethanol (to remove surface impurities and oxide layer) and then dried at room temperature for 3 min. The film sample was then fixed with a stainless steel electrode clamp (with the film sample surface in close contact with the stainless steel surface of the electrode clamp), exposing only 0.0435 cm². 2 The effective working area is used to prepare the working electrode.

[0048] 2. Test electrolyte preparation;

[0049] Prepare a 1 mol / L KOH electrolyte and pour it into a three-electrode electrolytic cell.

[0050] 3. Construction of electrochemical testing system;

[0051] A three-electrode testing system was adopted (see...). Figure 1 The working electrode is the above-mentioned LaNi 0.5 Fe 0.5 O3 thin film sample, with a platinum sheet (area 1 cm²) as the counter electrode. 2 The reference electrode is a mercury / mercury oxide (Hg / HgO) electrode; the three electrodes are inserted into the KOH electrolyte, ensuring that the electrodes do not contact each other and that the electrode surfaces are completely submerged.

[0052] 4. Electrochemical test parameter settings;

[0053] Turn on the electrochemical workstation and stabilize the test system for 10 min before testing; then perform cyclic voltammetry (CV) to test LaNi. 0.5 Fe 0.5 The surface of the O3 thin film sample was activated by scanning a voltage range of -0.45 ~ -0.35 V (vs. Hg / HgO) at a rate of 5 mV / s for 3 cycles until the CV curve stabilized. Then, linear sweep voltammetry (LSV) was performed with a voltage range of 0 ~ 2 V (vs. Hg / HgO) at a rate of 5 mV / s.

[0054] 5. Test data processing and analysis;

[0055] The reference electrode voltage data is converted to a voltage relative to the reversible hydrogen electrode (RHE) using the formula E. RHE =E Hg / HgO + 0.098 V + 0.059 × pH; Plot and analyze the curve using Origin software; Obtain the Tafel slope from the LSV curve to evaluate LaNi. 0.5 Fe 0.5 OER catalytic activity of O3 thin films.

[0056] Using the above method, LaNi was analyzed via an electrochemical workstation. 0.5 Fe 0.5 The OER catalytic performance of the O3 thin film was tested, and the results are as follows: Figure 2 As shown, at 10 mA / cm 2 LaNi at current density 0.5 Fe 0.5 The required potential for the O3 thin-film catalyst is 1.64 V. The Tafel slope obtained from the LSV curve is as follows: Figure 3 As shown, LaNi 0.5 Fe 0.5 The Tafel slope of the O3 thin-film catalyst is 74.4 mV / dec.

[0057] Example 2;

[0058] A La 0.9 Ni 0.5 Fe 0.5 The method for testing the OER catalytic performance of O3 thin film samples includes the following steps:

[0059] 1. Thin film sample pretreatment;

[0060] La-type materials with A-site defects were prepared using pulsed laser deposition. 0.9 Ni 0.5 Fe 0.5 O3 thin film samples: A lanthanum-nickel-iron-oxygen target (stoichiometric ratio of lanthanum, nickel, iron, and oxygen atoms was x:0.5:0.5:3, where x represents the A-site vacancy amount, with a value of 0.9) was used. The substrate was LaSrAlTaO3 (both the substrate and target were purchased from Hefei Single Crystal Materials Technology Co., Ltd.). The growth temperature was set at 700 ℃, the oxygen pressure at 100 mTorr, and the growth time at 1 hour. The pulsed laser repetition frequency was set at 2 Hz, and the energy density of the pulsed laser focused on the target was set at 1.23 J / cm². 2 .

[0061] The obtained thin film sample was cut into pieces approximately 0.25 x 0.25 cm. 2 Size (effective working area is 0.0575 cm²) 2 The film sample surface was gently wiped with anhydrous ethanol (to remove surface impurities and oxide layer) and then dried at room temperature for 3 min. The film sample was then fixed with a stainless steel electrode clamp (with the film sample surface in close contact with the stainless steel surface of the electrode clamp), exposing only 0.0575 cm². 2 The effective working area is used to prepare the working electrode.

[0062] 2. Test electrolyte preparation;

[0063] Prepare a 1 mol / L KOH electrolyte and pour it into a three-electrode electrolytic cell.

[0064] 3. Construction of electrochemical testing system;

[0065] A three-electrode testing system was adopted (see...). Figure 1 The working electrode is the aforementioned La. 0.9 Ni 0.5 Fe 0.5 O3 thin film sample, with a platinum sheet (area 1 cm²) as the counter electrode.2 The reference electrode is a mercury / mercury oxide (Hg / HgO) electrode; the three electrodes are inserted into the KOH electrolyte, ensuring that the electrodes do not contact each other and that the electrode surfaces are completely submerged.

[0066] 4. Electrochemical test parameter settings;

[0067] Turn on the electrochemical workstation and stabilize the test system for 10 min before testing; then, La was tested using cyclic voltammetry (CV). 0.9 Ni 0.5 Fe 0.5 The surface of the O3 thin film sample was activated by scanning a voltage range of -0.45 ~ -0.35 V (vs. Hg / HgO) at a rate of 5 mV / s for 3 cycles until the CV curve stabilized. Then, linear sweep voltammetry (LSV) was performed with a voltage range of 0 ~ 2 V (vs. Hg / HgO) at a rate of 5 mV / s.

[0068] 5. Test data processing and analysis;

[0069] The reference electrode voltage data is converted to a voltage relative to RHE using the following formula: E RHE = E Hg / HgO + 0.098V + 0.059 × pH; Plot and analyze curves using Origin software; Obtain the Tafel slope from the LSV curve to evaluate La 0.9 Ni 0.5 Fe 0.5 OER catalytic activity of O3 thin films.

[0070] Using the above method, La was analyzed via an electrochemical workstation. 0.9 Ni 0.5 Fe 0.5 The OER catalytic performance of the O3 thin film was tested, and the results are as follows: Figure 4 As shown, at 10 mA / cm 2 La at current density 0.9 Ni 0.5 Fe 0.5 The required potential for the O3 thin-film catalyst is 1.60 V. The Tafel slope obtained from the LSV curve is as follows: Figure 5 As shown, La 0.9 Ni 0.5 Fe 0.5 The Tafel slope of the O3 thin-film catalyst is 59.5 mV / dec.

[0071] Finally, LaNi 0.5 Fe 0.5 O3 thin film catalyst and La 0.9 Ni0.5 Fe 0.5 The OER catalytic performance of O3 thin-film catalysts was compared. The results are as follows: Figure 6 As shown, at an overpotential of 1.63 V, LaNi 0.5 Fe 0.5 The current density of the O3 thin-film catalyst is 9 mA / cm². 2 And La 0.9 Ni 0.5 Fe 0.5 The current density of the O3 thin-film catalyst reaches as high as 18 mA / cm². 2 It is LaNi 0.5 Fe 0.5 Twice that of O3 thin-film catalysts.

[0072] In summary, the electrocatalytic performance testing method for transition metal oxide thin films provided by this invention effectively avoids the problems of large result deviations and poor repeatability commonly found in existing methods for testing the electrocatalytic performance of thin film catalysts. This is achieved through standardized thin film sample pretreatment, precise preparation of test electrolytes, standardized electrochemical test system construction, systematic electrochemical testing, and a unified data processing and analysis workflow. Verification shows that this method can accurately reflect the electrocatalytic performance of transition metal oxide thin films, and the test results are reliable and comparable. The application of this method not only provides a scientifically unified standard for evaluating the electrocatalytic reaction performance of transition metal oxide thin films, but also provides precise data support for the composition optimization, structural regulation, and application promotion of similar thin film materials, significantly improving the efficiency of related research and development, and possessing significant practical application value and promising prospects for wider application.

[0073] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention.

Claims

1. A method for testing the electrocatalytic performance of transition metal oxide thin films, characterized in that, Includes the following steps: Step 1: Thin film sample pretreatment; A transition metal oxide thin film sample was selected and pretreated. The pretreated transition metal oxide thin film sample was fixed with a stainless steel electrode clamp so that the surface of the transition metal oxide thin film sample was in close contact with the stainless steel surface of the electrode clamp to obtain the working electrode. Step 2: Preparation of the test electrolyte; the test electrolyte is an alkaline electrolyte; Step 3: Construction of the electrochemical testing system; A three-electrode testing system is adopted, including a counter electrode, a reference electrode, and a working electrode. A platinum sheet is used as the counter electrode, and an SCE electrode, a Hg / HgO electrode, or an Ag / AgCl electrode is used as the reference electrode. The working electrode, counter electrode, and reference electrode are inserted into an alkaline electrolyte, with the electrodes in full contact with the alkaline electrolyte but not in contact with each other. Step 4: Setting electrochemical test parameters; Turn on the electrochemical workstation and set the stabilization time of the test system to the preset time before testing; Cyclic voltammetry and linear sweep voltammetry were performed sequentially to activate the transition metal oxide thin film sample and obtain the electrocatalytic oxygen evolution reaction activity data of the transition metal oxide thin film sample. Step 5: Test data processing and analysis; The reference electrode voltage data obtained during the test was converted into a potential relative to the reversible hydrogen electrode, and curve fitting and data analysis were performed to evaluate the electrocatalytic activity of the transition metal oxide thin film samples.

2. The method for testing the electrocatalytic performance of transition metal oxide thin films according to claim 1, characterized in that, In step 1, the substrate of the transition metal oxide thin film sample is LaSrAlTaO3, and the transition metal oxide thin film sample is La. x Ni 0.5 Fe 0.5 O3 thin film sample, where x is the amount of A-site vacancy defect, taking a value of 1.0 or 0.9; when x=1.0, LaNi 0.5 Fe 0.5 The effective working area of ​​the O3 thin film sample is 0.0435 cm². 2 When x=0.9, La 0.9 Ni 0.5 Fe 0.5 The effective working area of ​​the O3 thin film sample is 0.0575 cm². 2 .

3. The method for testing the electrocatalytic performance of transition metal oxide thin films according to claim 1, characterized in that, In step 1, the pretreatment includes: cutting the transition metal oxide thin film sample into a preset size, wiping the surface with anhydrous ethanol and drying at room temperature for 3-5 minutes.

4. The method for testing the electrocatalytic performance of transition metal oxide thin films according to claim 1, characterized in that, In step 2, the alkaline electrolyte is one or more of KOH solution, NaOH solution or LiOH solution, and the electrolyte concentration is 0.1~10 mol / L.

5. The method for testing the electrocatalytic performance of transition metal oxide thin films according to claim 4, characterized in that, The alkaline electrolyte is a KOH solution with a concentration of 1 mol / L.

6. The method for testing the electrocatalytic performance of transition metal oxide thin films according to claim 1, characterized in that, In step 3, the working electrode immerses only the preset effective working area of ​​the transition metal oxide film sample into the alkaline electrolyte, and the transition metal oxide film sample faces the platinum sheet.

7. The method for testing the electrocatalytic performance of transition metal oxide thin films according to claim 1, characterized in that, In step 3, the reference electrode is a mercury / mercury oxide electrode.

8. The method for testing the electrocatalytic performance of transition metal oxide thin films according to claim 1, characterized in that, In step 4: The electrochemical test was a test of the electrocatalytic oxygen evolution reaction; The preset time is 10~30 minutes; The conditions for cyclic voltammetry testing include: a scan voltage range of -0.5 to -0.4 V (vs. Hg / HgO), a scan rate of 5 to 100 mV / s, and 3 to 10 cycles until the CV curve stabilizes; The conditions for linear scanning voltammetry include: a scanning voltage range of 0 ~ 2 V (vs. Hg / HgO) and a scanning rate of 1 ~ 10 mV / s.

9. The method for testing the electrocatalytic performance of transition metal oxide thin films according to claim 8, characterized in that, In step 4: The conditions for cyclic voltammetry testing include: a scan voltage range of -0.45 ~ -0.35 V (vs. Hg / HgO), a scan rate of 5 mV / s, and 3 cycles. The conditions for linear scan voltammetry testing include: a scan voltage range of 0 ~ 2 V (vs. Hg / HgO) and a scan rate of 5 mV / s.

10. The method for testing the electrocatalytic performance of transition metal oxide thin films according to claim 1, characterized in that, In step 5, the conversion formula is: E RHE = E Hg / HgO + 0.098 V + 0.059 × pH; Origin software was used for curve fitting and data analysis. The Tafel slope was obtained from the linear sweep voltammetry curve to evaluate the reaction kinetics, and then the electrocatalytic oxygen evolution reaction activity of the transition metal oxide thin film samples was evaluated.

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