In-situ hydrogen measurement electro-reduction-electro-oxidation composite electrode and preparation method and application thereof

Abstract

The present application belongs to the technical field of hydrogen detection material produced by electrolysis of water, and relates to an in-situ hydrogen detection electro-reduction-electro-oxidation composite electrode and a preparation method and application thereof. The in-situ hydrogen detection electro-reduction-electro-oxidation composite electrode comprises a Pt / FTO electro-reduction electrode, an insulating glass separator and a Pt / FTO electro-oxidation electrode, and the coating on the surface of the Pt / FTO electro-reduction electrode and the Pt / FTO electro-oxidation electrode comprises an FTO layer in which platinum particles are dispersedly embedded; the proportion of Pt in the FTO layer is 0.5-1.5%. The application further discloses a preparation method and application of the in-situ hydrogen detection electro-reduction-electro-oxidation composite electrode. The in-situ hydrogen detection electro-reduction-electro-oxidation composite electrode can in-situ detect trace hydrogen in the process of electrocatalytic decomposition of water at an extremely low potential, and has the advantages of high detection sensitivity and low energy consumption.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen production and detection materials for electrolysis of water, and relates to an in-situ hydrogen detection electro-reduction-electro-oxidation composite electrode and a preparation method and application thereof. BACKGROUND

[0002] The energy crisis has opened up the exploration of hydrogen energy development and utilization, and among them, the electrocatalytic decomposition of water to produce hydrogen is one of the effective ways to obtain green hydrogen energy. However, due to the high energy barrier of the four-electron mechanism involved in the anode oxygen evolution half-reaction of the electrocatalytic decomposition of water, the efficiency of the cathode hydrogen evolution half-reaction is reduced, therefore, the development of high-activity and low-cost catalysts is the key to realizing the efficient electrocatalytic decomposition of water to produce hydrogen. The activity of the catalyst can be directly represented by the amount of hydrogen evolution during the reaction process, and the most widely used quantitative analysis of the electrocatalytic decomposition of water to produce hydrogen technology mainly includes gas chromatography and electrochemical hydrogen sensor detection. Among them, the gas chromatography has fast analysis speed and high sensitivity, and the detection limit can reach μmol / L. The electrochemical hydrogen sensor has fast response speed and can determine the change of hydrogen concentration in the reaction system with time in real time, and the detection limit can reach μmol / L, but it needs to be calibrated before each test, which takes a long time.

[0003] The dual-function composite electrode based on the principle of electrochemical reaction can simultaneously realize the electro-oxidation and electro-reduction reactions, and has simple manufacturing process and small size, and has been applied to the detection of oxygen production in some neutral solution systems. However, the electro-oxidation electrode for oxygen evolution needs high voltage input (~2.23V vs RHE), and the electro-reduction electrode for oxygen collection also needs to apply a voltage of ~-0.217V (vs RHE). In addition, under the same reaction conditions, the voltage applied to the electro-reduction electrode must be less than -0.367V (vs RHE) to realize hydrogen evolution, which will cause irreversible damage to the electrode surface, therefore, from the perspective of energy consumption cost and electrode stability, the dual-function composite electrode for hydrogen production detection still has challenges.

[0004] The electrocatalytic hydrogen production technology in acidic solution system is widely considered as the best choice for hydrogen production system due to its high current density, fast reaction kinetics and high energy conversion efficiency, however, most electrocatalysts have poor stability in strong acidic solution, and are prone to electrode surface corrosion and degradation of catalytic performance, and the strong acid system will cause irreversible damage to the hydrogen detection instrument components. The weak acid solution system can provide more favorable conditions for catalyst stability and electrode corrosion resistance, thereby prolonging the service life of the catalyst and equipment.

[0005] Therefore, it is of great significance to seek a method for detecting hydrogen in weak acid solution system, which has simple process, high sensitivity, real-time determination and low energy consumption, and to increase the selectivity of the electrocatalytic decomposition of water to produce hydrogen detection method and to screen efficient hydrogen evolution electrocatalysts. SUMMARY

[0006] The application aims at solving the above problems existing in the prior art, and provides an in-situ hydrogen measurement electro-reduction-electro-oxidation composite electrode with simple process and low energy consumption.

[0007] The application aims at solving the above problems existing in the prior art, and provides an in-situ hydrogen measurement electro-reduction-electro-oxidation composite electrode with simple process and low energy consumption.

[0008] An in-situ hydrogen measurement electro-reduction-electro-oxidation composite electrode, which is composed of a Pt / FTO electro-reduction electrode, an insulating glass separator and a Pt / FTO electro-oxidation electrode,

[0009] The coating on the surface of the Pt / FTO electro-reduction electrode and the Pt / FTO electro-oxidation electrode comprises an FTO layer in which platinum particles are dispersedly embedded, and the proportion of Pt in the FTO layer is 0.5-1.5%.

[0010] Preferably, the distance between the Pt / FTO electro-reduction electrode and the Pt / FTO electro-oxidation electrode is 1.0 mm.

[0011] Preferably, the thickness of the insulating glass separator is 1.0 mm, and the thickness of the coating on the surface of the Pt / FTO electro-reduction electrode and the Pt / FTO electro-oxidation electrode is 0.2-0.3 μm.

[0012] Preferably, the insulating glass separator, the Pt / FTO electro-reduction electrode and the Pt / FTO electro-oxidation electrode are all pasted by inert epoxy resin.

[0013] The distance between the Pt / FTO electro-reduction electrode and the Pt / FTO electro-oxidation electrode is measured by the thickness of the insulating glass separator, and the thickness of the bonding material is ignored.

[0014] In the application, the distance between the Pt / FTO electro-reduction electrode and the Pt / FTO electro-oxidation electrode needs to be controlled at 1.0 mm to ensure good electron transmission and thus obtain better hydrogen collection efficiency.

[0015] Preferably, the Pt / FTO electro-reduction electrode and the Pt / FTO electro-oxidation electrode are prepared by cutting an angle on the upper side of the FTO conductive glass, coating an isopropanol solution of chloroplatinic acid hexahydrate on the surface of the lower side conductive layer, naturally air-drying and pyrolyzing.

[0016] Preferably, the size of the surface area of the lower side conductive layer coated with chloroplatinic acid hexahydrate is 1*1 cm.

[0017] Preferably, the concentration of chloroplatinic acid hexahydrate in the isopropanol solution of chloroplatinic acid hexahydrate is 2.0-4.0 mg / ml.

[0018] Further preferably, the coating amount of the isopropanol solution of chloroplatinic acid hexahydrate is 0.1-0.2 g / cm 2 .

[0019] Preferably, the pyrolysis temperature is 300-390℃, the time is 20-50 min, and the heating rate is 5-15℃ / min.

[0020] Preferably, the FTO conductive glass has a thickness of 1.6-2.2 mm, a resistance of 7-14 Ω, and a light transmittance of 80-90%.

[0021] Preferably, one corner of the upper side of the Pt / FTO electro-reduction electrode and the Pt / FTO electro-oxidation electrode is cut, and the other corner of the upper side is coated with conductive silver glue.

[0022] When one corner of the upper side of the electrode is cut and the two conductive surfaces are pasted against each other, the area coated with conductive silver glue can be separated, which is convenient for operation and avoids short circuit.

[0023] The application also discloses a preparation method of the in-situ hydrogen measurement electro-reduction-electro-oxidation composite electrode.

[0024] S1, coating the isopropanol solution of chloroplatinic acid hexahydrate on the surface of the lower side conductive layer of the FTO conductive glass, and preparing the Pt / FTO electrode through natural air drying and pyrolysis;

[0025] S2, cutting one corner of the upper side of the Pt / FTO electrode, and coating the other corner of the upper side with conductive silver glue to connect the lead wire;

[0026] S3, pasting the two Pt / FTO electrodes against each other, and arranging an insulating glass spacer between the two Pt / FTO electrodes; one of the two Pt / FTO electrodes is a Pt / FTO electro-reduction electrode, and the other is a Pt / FTO electro-oxidation electrode.

[0027] The application also discloses application of the in-situ hydrogen measurement electro-reduction-electro-oxidation composite electrode in electro-catalytic water decomposition hydrogen production detection, and the in-situ hydrogen measurement electro-reduction-electro-oxidation composite electrode is used as a working electrode in the electro-catalytic water decomposition hydrogen production detection.

[0028] Preferably, the electro-catalytic water decomposition hydrogen production detection process comprises an initial stage, a synchronous treatment stage and a post-treatment stage.

[0029] Further preferably, in the initial stage, an electro-reduction reaction is carried out, the Pt / FTO electro-reduction electrode is used as a cathode, a voltage of -0.02 to -0.25 V (vs RHE) is applied, and the cathode voltage is maintained for 30-90 seconds.

[0030] In the initial stage, the Pt / FTO electrode in the hydrogen in-situ measurement electro-reduction-electro-oxidation composite electrode is applied with a reduction voltage to reduce hydrogen ions in the solution system into hydrogen, so as to achieve the purpose of hydrogen production.

[0031] Further preferably, in the synchronous treatment stage, the electro-reduction and electro-oxidation reactions are simultaneously performed, the Pt / FTO electrode is used as a cathode, the Pt / FTO electrode is used as an anode, the voltage applied to the cathode is-0.02 to-0.25 V (vs RHE), the voltage applied to the anode is 0.5 to 1.0 V (vs RHE), and the voltage maintaining time is 30 to 90 minutes.

[0032] In the synchronous treatment stage, hydrogen is continuously generated on the surface of the Pt / FTO electrode and diffuses to the surface of the Pt / FTO electrode, the H2 is oxidized by applying an oxidation voltage, the hydrogen evolution amount at the reduction electrode is converted into an intuitive oxidation current response, and it is proved that the composite electrode can realize in-situ hydrogen measurement.

[0033] Further preferably, in the post-treatment stage, the residual H2 is removed by electro-oxidation, the voltage applied to the Pt / FTO electrode is removed, the voltage applied to the Pt / FTO electrode anode is kept unchanged, and the voltage maintaining time is 10 to 20 minutes.

[0034] In the post-treatment stage, the residual H2 is ensured to be re-oxidized into hydrogen ions, an oxidation current response is generated at the oxidation electrode, and thus the actual collection efficiency of the oxidation electrode reaches a maximum value.

[0035] Preferably, the application process is performed in an electrolyte solution, and the electrolyte solution is a weak acid solution with a pH of 4.0 to 6.0.

[0036] Further preferably, the solute in the weak acid solution is one or more of sodium nitrate, sodium sulfate and sodium perchlorate, and the solvent is acetic acid and / or sodium acetate buffer solution.

[0037] Further preferably, the concentration of the solvent is 0.05 to 0.2 mol / L, and the concentration of the solute is 0.1 to 1.5 mol / L.

[0038] Preferably, the hydrogen collection efficiency of the oxidation electrode in the electro-catalytic water decomposition hydrogen production detection can reach 62%.

[0039] Compared with the prior art, the application has the following beneficial effects:

[0040] 1. The Pt particles loaded on the surface of the FTO layer in the hydrogen in-situ measurement electro-reduction-electro-oxidation composite electrode of the application have high electro-catalytic activity; the adsorption and desorption of hydrogen on the surface of the Pt particles are rapid reaction processes, and H2 can be quickly measured at low energy consumption. +The response current value of the H2 reaction is used for quantifying the hydrogen production amount.

[0041] 2、The in-situ hydrogen measuring electro-reduction-electro-oxidation composite electrode of the application can in-situ measure trace hydrogen in the process of electrocatalytic water decomposition at very low potential, and has the advantages of high sensitivity and low energy consumption.

[0042] 3、The in-situ hydrogen measuring electro-reduction-electro-oxidation composite electrode of the application has simple and controllable preparation method.

[0043] 4、In the process of measuring hydrogen production in the electrocatalytic water decomposition, part of the electrolyte solution enters the gap of the composite electrode through capillary action, and H2 generated from the surface of the Pt / FTO electro-reduction cathode gathers in the gap after applying voltage, only a small amount of H2 escapes from the electrolyte solution above the gap, thus amplifying the signal value of H2, and after a stable concentration gradient is established between the composite electrodes, the Pt / FTO electro-oxidation anode converts the hydrogen evolution amount into an intuitive oxidation current value through the oxidation of H2.

[0044] 5、The in-situ hydrogen measuring electro-reduction-electro-oxidation composite electrode of the application has low energy consumption in the process of measuring hydrogen production in the electrocatalytic water decomposition, can respond in real time, and has stable operation, which has important significance for the selection and optimization of electrode components, catalysts and electrolyte in the electrocatalytic water decomposition system. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 It is a structural schematic diagram of the in-situ hydrogen measuring electro-reduction-electro-oxidation composite electrode of the application.

[0046] Figure 2 It is a SEM diagram of the Pt / FTO electrode prepared in Example 1 of the application, wherein a is FTO and b is Pt / FTO.

[0047] Figure 3 It is a LSV curve diagram of the Pt / FTO electrode prepared in the application application example 1.

[0048] Figure 4 It is a cyclic voltammetry curve diagram of the in-situ hydrogen measuring electro-reduction-electro-oxidation composite electrode prepared in the application application example 1.

[0049] Figure 5 It is a working principle diagram of the in-situ hydrogen measuring electro-reduction-electro-oxidation composite electrode prepared in the application application example 1.

[0050] Figure 6 It is a current-time curve diagram of the in-situ hydrogen measuring electro-reduction-electro-oxidation composite electrode prepared in the application application example 1, wherein a is the electro-reduction cathode current-time curve diagram, and b is the electro-oxidation anode current-time curve diagram.

[0051] Figure 7 The charge-time curve of the in-situ hydrogen measurement electroreduction-electrooxidation composite electrode prepared in Example 1 of this invention is shown. Detailed Implementation

[0052] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0053] Example 1

[0054] The in-situ hydrogen measurement electroreduction-electrooxidation composite electrode in this embodiment consists of a Pt / FTO electroreduction electrode, an insulating glass septum, and a Pt / FTO electrooxidation electrode. The insulating glass septum has dimensions of 1cm*10mm*1mm, and the distance between the Pt / FTO electroreduction electrode and the Pt / FTO electrooxidation electrode is 1mm.

[0055] The specific preparation processes for the Pt / FTO electroreduction electrode and the Pt / FTO electrooxidation electrode include:

[0056] After cleaning the 2.2mm thick FTO conductive glass, blow it dry with nitrogen gas, and then stick it to the conductive surface 1cm away from the bottom with cellulose acetate film tape.

[0057] Chloroplatinic acid hexahydrate was thoroughly mixed with isopropanol solvent under ultrasonication to obtain a mixed solution with a concentration of 3.2 mg / ml;

[0058] The mixed solution was applied to the area at the bottom of the FTO conductive glass not covered by cellulose acetate film tape, with a coating amount of 0.15 g / cm². 2 The Pt / FTO electrode was naturally air-dried in a fume hood at room temperature, the cellulose acetate film tape was removed, and the electrode was placed in a muffle furnace for pyrolysis at 380℃ for 30 min at a heating rate of 8℃ / min to obtain a Pt / FTO electrode with a Pt content of 1.0% in the FTO layer.

[0059] Cut the Pt / FTO electrode into small pieces of 4cm×1cm. On the conductive surface of each electrode, make a 20mm diagonal cut from the top to the bottom right along the right side. Attach the wire to the upper left corner of the conductive surface of the Pt / FTO electrode with conductive silver paste.

[0060] Two Pt / FTO electrodes were used as Pt / FTO electroreduction electrode and Pt / FTO electrooxidation electrode, respectively. The conductive surfaces of the two electrodes faced each other, and an insulating glass sheet was placed in the middle. The three were connected by inert epoxy resin to obtain an in-situ hydrogen measurement electroreduction-electrooxidation composite electrode.

[0061] Figure 1 This is a schematic diagram of the structure of an electroreduction-electrooxidation composite electrode for in-situ hydrogen measurement.

[0062] Figure 2 SEM images of Pt / FTO electrodes, where a represents FTO and b represents Pt / FTO. Figure 2 As can be seen in b, Pt is uniformly covered on the substrate surface, indicating that Pt particles were successfully loaded onto the FTO conductive glass.

[0063] Example 2

[0064] The in-situ hydrogen measurement electroreduction-electrooxidation composite electrode in this embodiment consists of a Pt / FTO electroreduction electrode, an insulating glass septum, and a Pt / FTO electrooxidation electrode. The insulating glass septum has dimensions of 1cm*10mm*1mm, and the distance between the Pt / FTO electroreduction electrode and the Pt / FTO electrooxidation electrode is 1mm.

[0065] The specific preparation processes for the Pt / FTO electroreduction electrode and the Pt / FTO electrooxidation electrode include:

[0066] After cleaning the 2.2mm thick FTO conductive glass, blow it dry with nitrogen gas, and then stick it to the conductive surface 1cm away from the bottom with cellulose acetate film tape.

[0067] Chloroplatinic acid hexahydrate was thoroughly mixed with isopropanol solvent under ultrasound to obtain a mixed solution with a concentration of 3.6 mg / ml.

[0068] The mixed solution was applied to the area at the bottom of the FTO conductive glass not covered by cellulose acetate film tape, with a coating amount of 0.16 g / cm². 2 The material was air-dried naturally in a fume hood at room temperature, the cellulose acetate film tape was removed, and the material was placed in a muffle furnace for pyrolysis at 385℃ for 30 min at a heating rate of 10℃ / min to obtain a Pt / FTO electrode with a Pt content of 1.2% in the FTO layer.

[0069] Cut the Pt / FTO electrode into small pieces of 4cm×1cm. On the conductive surface of each electrode, make a 20mm diagonal cut from the top to the bottom right along the right side. Attach the wire to the upper left corner of the conductive surface of the Pt / FTO electrode with conductive silver paste.

[0070] Two Pt / FTO electrodes were used as Pt / FTO electroreduction electrode and Pt / FTO electrooxidation electrode, respectively. The conductive surfaces of the two electrodes faced each other, and an insulating glass sheet was placed in the middle. The three were connected by inert epoxy resin to obtain an in-situ hydrogen measurement electroreduction-electrooxidation composite electrode.

[0071] Example 3

[0072] The in-situ hydrogen measurement electroreduction-electrooxidation composite electrode in this embodiment consists of a Pt / FTO electroreduction electrode, an insulating glass septum, and a Pt / FTO electrooxidation electrode. The insulating glass septum has dimensions of 1cm*10mm*1mm, and the distance between the Pt / FTO electroreduction electrode and the Pt / FTO electrooxidation electrode is 1mm.

[0073] Compared with Example 1, the difference lies in that the concentration of the mixed solution of chloroplatinic acid hexahydrate and isopropanol solvent is 4.0 mg / ml during the preparation of the Pt / FTO electro-oxidation electrode, and the proportion of Pt in the FTO layer of the Pt / FTO electrode is 1.4%.

[0074] The Pt / FTO electroreduction electrode prepared according to the method in Example 1 and the Pt / FTO electrooxidation electrode prepared according to the method of this example are assembled to obtain an in-situ hydrogen measurement electroreduction-electrooxidation composite electrode.

[0075] Example 4

[0076] The in-situ hydrogen measurement electroreduction-electrooxidation composite electrode in this embodiment consists of a Pt / FTO electroreduction electrode, an insulating glass septum, and a Pt / FTO electrooxidation electrode. The insulating glass septum has dimensions of 1cm*10mm*1mm, and the distance between the Pt / FTO electroreduction electrode and the Pt / FTO electrooxidation electrode is 1mm.

[0077] The difference from Example 1 is that the concentration of the mixed solution of chloroplatinic acid hexahydrate and isopropanol solvent is 3.0 mg / ml.

[0078] The Pt content in the FTO layer of the prepared Pt / FTO electrode is 0.9%.

[0079] Example 5

[0080] The in-situ hydrogen measurement electroreduction-electrooxidation composite electrode in this embodiment consists of a Pt / FTO electroreduction electrode, an insulating glass septum, and a Pt / FTO electrooxidation electrode. The insulating glass septum has dimensions of 1cm*10mm*1mm, and the distance between the Pt / FTO electroreduction electrode and the Pt / FTO electrooxidation electrode is 1mm.

[0081] The difference compared to Example 1 is that the pyrolysis temperature is 395°C.

[0082] The Pt content in the FTO layer of the prepared Pt / FTO electrode is 1.6%.

[0083] Example 6

[0084] The in-situ hydrogen measurement electroreduction-electrooxidation composite electrode in this embodiment consists of a Pt / FTO electroreduction electrode, an insulating glass septum, and a Pt / FTO electrooxidation electrode. The insulating glass septum has dimensions of 1cm*10mm*1mm, and the distance between the Pt / FTO electroreduction electrode and the Pt / FTO electrooxidation electrode is 1mm.

[0085] Compared with Example 1, the difference is that the pyrolysis temperature is 290°C and the time is 40 min.

[0086] The Pt content in the FTO layer of the prepared Pt / FTO electrode is 0.4%.

[0087] Application Example 1

[0088] The in-situ hydrogen measurement electroreduction-electrooxidation composite electrode from Example 1 was applied to the detection of hydrogen produced by electrocatalytic water splitting, specifically including:

[0089] Prepare an acetate / sodium acetate buffer solution with an acetate concentration of 0.1 mol / L, add 0.5 mol / L sodium nitrate as an electrolyte, and adjust the pH to 4.56;

[0090] Initial stage: The Pt / FTO electroreduction electrode is pretreated; using the Pt / FTO electroreduction electrode as the cathode, the Ag / AgCl electrode as the reference electrode, and the platinum wire electrode as the counter electrode, a voltage of -0.134V (vs RHE) is applied to the Pt / FTO electroreduction cathode and held for 60 seconds.

[0091] During the simultaneous treatment phase, the electroreduction and electrooxidation reactions proceed simultaneously. The Pt / FTO electroreduction electrode serves as the cathode, and the Pt / FTO electrooxidation electrode serves as the anode. The voltage applied to the cathode remains constant, while the voltage applied to the anode is 0.866V (vs RHE), and the voltage is maintained for 66 minutes.

[0092] In the post-treatment stage, the remaining H2 is removed by electro-oxidation. The voltage applied by the Pt / FTO electroreduction electrode is removed, while the voltage applied by the Pt / FTO electro-oxidation anode remains unchanged for 15 minutes.

[0093] Integrating the current over time, the accumulated charges on the electroreduction cathode and electrooxidation anode were found to be 0.839C and 0.527C, respectively. According to Faraday's second law, these translate to actual hydrogen evolution and actual collection amounts of 4.35 × 10⁻⁶. - 6 mol and 2.73 × 10 -6 The actual collection efficiency was 62.76% (mol).

[0094] Figure 3The LSV curve of the Pt / FTO electrode prepared in this application embodiment shows that when the voltage applied to the electroreduction cathode is in the range of -0.026 to -0.226 V (vs RHE), it is sufficient for the hydrogen evolution reaction to occur and a response current to be generated.

[0095] Figure 4 This is a cyclic voltammetry curve of the Pt / FTO electrode prepared in this application example. For the Pt / FTO electrode, the cyclic voltammetry curve is non-rectangular, indicating a reversible redox reaction. Furthermore, when the voltage applied to the electro-oxidizing anode is in the range of 0.574–0.974 V (vs RHE), it is sufficient to convert H2 to H2. + And generate a response current.

[0096] Figure 5 This is a schematic diagram illustrating the working principle of the Pt / FTO electroreduction-electrooxidation composite electrode prepared in this application example; it can be seen that during in-situ hydrogen measurement, the H in the electrolyte solution... + The H2 is reduced to H2 at the surface of the electroreduction cathode, and then diffuses to the surface of the electrooxidation anode, where it is oxidized to H2. + .

[0097] Figure 6 The image shows the current-time curves of the Pt / FTO electroreduction-electrooxidation composite electrode prepared in this application embodiment, where a is the current-time curve of the electroreduction cathode and b is the current-time curve of the electrooxidation anode; from Figure 6 As can be seen from a, the hydrogen evolution process occurs from 0 to 4000 seconds. After 4000 seconds, the voltage on the electroreduction cathode is removed, hydrogen evolution stops, and the reduction current is 0. Figure 6 In step b, the H2 oxidation process takes place from 60 to 4000 seconds. After 4000 seconds, the amount of H2 diffusing to the surface of the electro-oxidizing anode gradually decreases, and the oxidation current gradually approaches 0.

[0098] Figure 7 This is a charge-time curve of the Pt / FTO electroreduction-electrooxidation composite electrode prepared in this application embodiment. It can be seen that the accumulated charge at the electroreduction cathode is greater than that at the electrooxidation anode. This is mainly because some of the H2 precipitated at the electroreduction cathode escapes from the solution above the gaps in the component and cannot diffuse to the surface of the electrooxidation anode to be oxidized to H2. + .

[0099] Application Example 2

[0100] The in-situ hydrogen measurement electroreduction-electrooxidation composite electrode from Example 1 was applied to the detection of hydrogen produced by electrocatalytic water splitting, specifically including:

[0101] Prepare an acetate / sodium acetate buffer solution with an acetate concentration of 0.1 mol / L, add 0.5 mol / L sodium nitrate as an electrolyte, and adjust the pH to 4.56;

[0102] Initial stage: The Pt / FTO electroreduction electrode is pretreated; using the Pt / FTO electroreduction electrode as the cathode, the Ag / AgCl electrode as the reference electrode, and the platinum wire electrode as the counter electrode, a voltage of -0.134V (vs RHE) is applied to the Pt / FTO electroreduction cathode and held for 60 seconds.

[0103] During the simultaneous treatment phase, the electroreduction and electrooxidation reactions proceed simultaneously. The Pt / FTO electroreduction electrode serves as the cathode, and the Pt / FTO electrooxidation electrode serves as the anode. The voltage applied to the cathode remains constant, while the voltage applied to the anode is 0.966V (vs RHE), and the voltage is maintained for 66 minutes.

[0104] In the post-treatment stage, the remaining H2 is removed by electro-oxidation. The voltage applied by the Pt / FTO electroreduction electrode is removed, while the voltage applied by the Pt / FTO electro-oxidation anode remains unchanged for 15 minutes.

[0105] Integrating the current over time, the accumulated charges on the electroreduction cathode and electrooxidation anode were found to be 2.99C and 0.751C, respectively. According to Faraday's second law, these translate to actual hydrogen evolution and actual collection amounts of 1.55 × 10⁻⁶. - 5 mol and 3.89×10 -6 The actual collection efficiency was 25.10% (mol).

[0106] Application Example 3

[0107] The in-situ hydrogen measurement electroreduction-electrooxidation composite electrode from Example 1 was applied to the detection of hydrogen produced by electrocatalytic water splitting, specifically including:

[0108] Prepare an acetate / sodium acetate buffer solution with an acetate concentration of 0.1 mol / L, add 0.5 mol / L sodium nitrate as an electrolyte, and adjust the pH to 4.56;

[0109] Initial stage: The Pt / FTO electroreduction electrode is pretreated; using the Pt / FTO electroreduction electrode as the cathode, the Ag / AgCl electrode as the reference electrode, and the platinum wire electrode as the counter electrode, a voltage of -0.134V (vs RHE) is applied to the Pt / FTO electroreduction cathode and held for 60 seconds.

[0110] During the simultaneous treatment phase, the electroreduction and electrooxidation reactions proceed simultaneously. The Pt / FTO electroreduction electrode serves as the cathode, and the Pt / FTO electrooxidation electrode serves as the anode. The voltage applied to the cathode remains constant, while the voltage applied to the anode is 0.666V (vs RHE), and the voltage is maintained for 66 minutes.

[0111] In the post-treatment stage, the remaining H2 is removed by electro-oxidation. The voltage applied by the Pt / FTO electroreduction electrode is removed, while the voltage applied by the Pt / FTO electro-oxidation anode remains unchanged for 15 minutes.

[0112] Integrating the current over time, the accumulated charges on the electroreduction cathode and electrooxidation anode were found to be 1.366C and 0.678C, respectively. According to Faraday's second law, these translate to actual hydrogen evolution and actual collection amounts of 7.08 × 10⁻⁶. - 6 mol and 3.51×10 -6 The actual collection efficiency was 49.58%.

[0113] Application Example 4

[0114] Compared with Application Example 2, the difference lies in the preparation of an acetate / sodium acetate buffer solution with an acetate concentration of 0.1 mol / L, the addition of 0.25 mol / L sodium nitrate as an electrolyte, and the adjustment of pH to 4.56.

[0115] Integrating the current over time, the accumulated charges on the electroreduction cathode and electrooxidation anode were found to be 0.142C and 0.043C, respectively. According to Faraday's second law, these translate to actual hydrogen evolution and actual collection amounts of 7.36 × 10⁻⁶. - 7 mol and 2.23 × 10 -6 The actual collection efficiency was 23.30% (mol).

[0116] Application Example 5

[0117] Compared with Application Example 2, the difference is that an acetate / sodium acetate buffer solution with an acetate concentration of 0.1 mol / L was prepared, 1.0 mol / L sodium nitrate was added as an electrolyte, and the pH was adjusted to 4.56.

[0118] Integrating the current over time, the accumulated charges on the electroreduction cathode and electrooxidation anode were found to be 0.237C and 0.023C, respectively. According to Faraday's second law, these translate to actual hydrogen evolution and actual collection amounts of 1.24 × 10⁻⁶. - 6 mol and 1.19×10 -7 The actual collection efficiency was 9.70% (mol).

[0119] Application Example 6

[0120] The Pt / FTO electrode prepared in Example 2 was tested according to the method described in Application Example 2, and the actual collection efficiency was found to be 23.2%.

[0121] Application Example 7

[0122] The Pt / FTO electrode prepared in Example 3 was tested according to the method described in Application Example 2, and the actual collection efficiency was found to be 20.1%.

[0123] Application Example 8

[0124] The Pt / FTO electrode prepared in Example 4 was tested according to the method described in Application Example 2, and the actual collection efficiency was found to be 21.4%.

[0125] Application Example 9

[0126] The Pt / FTO electrode prepared in Example 5 was tested according to the method described in Application Example 2, and the actual collection efficiency was found to be 12.3%.

[0127] Application Example 10

[0128] The Pt / FTO electrode prepared in Example 6 was tested according to the method described in Application Example 2, and the actual collection efficiency was only 6.5%.

[0129] Application Comparative Example 1

[0130] Compared to Application Example 1, the difference lies in the synchronous processing stage, where the voltage applied to the Pt / FTO electro-oxidation anode is 0.5V (vs RHE).

[0131] The actual collection efficiency for hydrogen production from electrocatalytic water splitting was 26.91%.

[0132] Application Comparative Example 2

[0133] Compared to Application Example 1, the difference lies in the synchronous processing stage, where the voltage applied to the Pt / FTO electro-oxidation anode is 1.2V (vs RHE).

[0134] The actual collection efficiency for hydrogen production from electrocatalytic water splitting was 14.04%.

[0135] As can be seen from the above, the in-situ hydrogen measurement electroreduction-electrooxidation composite electrode with a Pt content of 0.5-1.5% in the FTO layer on the electrode surface of the present invention can play a good role in the detection of hydrogen production from electrocatalytic water splitting.

[0136] As shown in Application Examples 1-3 and Comparative Examples 1-2, the actual collection efficiency of the composite electrode is relatively high when the applied voltage at the electro-oxidation anode is between 0.666 and 0.966 V (vs RHE). As shown in Application Examples 2, 4, and 5, the concentration of sodium nitrate affects the oxidation efficiency of H2 at the electro-oxidation anode; the higher the sodium nitrate concentration, the less H2 is oxidized. This is mainly due to capacitive interference between the reduction and oxidation electrodes, which prevents most of the H2 diffusing to the electro-oxidation anode from being oxidized to H2. + .

[0137] As can be seen from Examples 1 to 6, the concentration of the mixed solution of chloroplatinic acid hexahydrate and isopropanol solvent, as well as the adjustment of parameters during the preparation process, will affect the proportion of Pt in the FTO layer; as can be seen from Application Examples 1 to 10, the adjustment of voltage, electrolyte, etc. during the detection process will affect the hydrogen production performance.

[0138] In summary, the Pt particles loaded on the FTO layer surface through pyrolysis in the in-situ hydrogen measurement electroreduction-electrooxidation composite electrode of the present invention have high electrocatalytic activity. Using this in-situ hydrogen measurement electroreduction-electrooxidation composite electrode, trace amounts of hydrogen can be measured in situ at extremely low potentials during the electrocatalytic water splitting process, which has the advantages of high detection sensitivity and low energy consumption.

[0139] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. An in-situ hydrogen measurement electroreduction-electrooxidation composite electrode, characterized in that, The in-situ hydrogen measurement electroreduction-electrooxidation composite electrode is composed of a Pt / FTO electroreduction electrode, an insulating glass septum, and a Pt / FTO electrooxidation electrode. The Pt / FTO electroreduction electrode and the Pt / FTO electrooxidation electrode are prepared by cutting a corner on the upper side of FTO conductive glass, coating the lower conductive layer surface with an isopropanol solution of chloroplatinic acid hexahydrate, air-drying, and then pyrolyzing. The pyrolysis temperature is 300~390℃, the time is 20~50min, and the heating rate is 5~15℃ / min. The concentration of chloroplatinic acid hexahydrate in the isopropanol solution is 2.0~4.0mg / ml, and the coating amount of the isopropanol solution is 0.1~0.2g / cm³. 2 ; The coating on the surface of the Pt / FTO electroreduction electrode and the Pt / FTO electrooxidation electrode includes an FTO layer in which platinum particles are dispersed and embedded; the proportion of Pt in the FTO layer is 0.5~1.5%.

2. The in-situ hydrogen measurement electroreduction-electrooxidation composite electrode according to claim 1, characterized in that, The distance between the Pt / FTO electroreduction electrode and the Pt / FTO electrooxidation electrode is 1 mm.

3. A method for preparing an in-situ hydrogen measurement electroreduction-electrooxidation composite electrode as described in claim 1, characterized in that, The preparation method includes: S1. A Pt / FTO electrode is prepared by coating the surface of the conductive layer on the lower side of FTO conductive glass with an isopropanol solution of chloroplatinic acid hexahydrate, and then air-drying and pyrolyzing it. S2, one corner of the upper side of the Pt / FTO electrode is cut off, and the other corner of the upper side is coated with conductive silver paste to connect the wires; S3. Attach two Pt / FTO electrodes facing each other, with an insulating glass spacer between them; one Pt / FTO electrode is a Pt / FTO electroreduction electrode and the other is a Pt / FTO electrooxidation electrode.

4. The application of an in-situ electroreduction-electrooxidation composite electrode for hydrogen measurement in the detection of hydrogen produced by electrocatalytic water splitting, characterized in that, In the detection of hydrogen production from electrocatalytic water splitting, the in-situ hydrogen measurement electroreduction-electrooxidation composite electrode as described in any one of claims 1 to 2 is used as the working electrode.

5. The application of the in-situ hydrogen measurement electroreduction-electrooxidation composite electrode according to claim 4 in the detection of hydrogen produced by electrocatalytic water splitting, characterized in that, The application is carried out in an electrolyte solution, which is a weakly acidic solution with a pH of 4.0 to 6.

0.

6. The application of the in-situ hydrogen measurement electroreduction-electrooxidation composite electrode according to claim 5 in the detection of hydrogen produced by electrocatalytic water splitting, characterized in that, The solute in the weakly acidic solution is one or more of sodium nitrate, sodium sulfate, and sodium perchlorate, and the solvent is acetic acid and / or sodium acetate buffer solution.

7. The application of the in-situ hydrogen measurement electroreduction-electrooxidation composite electrode according to claim 4 in the detection of hydrogen produced by electrocatalytic water splitting, characterized in that, The electrocatalytic water splitting hydrogen production detection process includes an initial stage, a simultaneous treatment stage, and a post-treatment stage.

8. The application of the in-situ hydrogen measurement electroreduction-electrooxidation composite electrode according to claim 4 in the detection of hydrogen produced by electrocatalytic water splitting, characterized in that, The hydrogen collection efficiency of the oxidation electrode in the detection of hydrogen production from electrocatalytic water splitting reaches 62%.

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