A method for quantitatively analyzing photoelectrochemical performance based on polarization potential calibration

Abstract

The present application relates to the technical field of photoelectrochemical performance analysis, and discloses a method for quantitatively analyzing photoelectrochemical performance based on polarization potential calibration, which comprises the following steps: (1) in a three-electrode system, photo-induced OCP of a semiconductor electrode with a photoelectric functional coating is tested under solution environment and light, and a photo-induced polarization curve of the semiconductor electrode is obtained; (2) in a three-electrode system, dark-state OCP of the semiconductor electrode is tested under solution environment and closed light, and a dark-state polarization curve of the semiconductor electrode is obtained; (3) according to the photo-induced polarization curve and the dark-state polarization curve, a semi-logarithmic polarization curve, a current density-potential curve, a ΔE-i curve and a ΔE-Δi curve are obtained; and (4) photoelectrochemical performance of the semiconductor electrode is analyzed according to the curves. The method can directly characterize actual photo-induced current density of the photoelectric functional coating and quantitatively analyze electrochemical performance thereof.

Description

Technical Field

[0001] This invention relates to the field of photoelectrochemical performance analysis technology, and in particular to a method for quantitative analysis of photoelectrochemical performance based on polarization potential calibration. Background Technology

[0002] The photoelectrochemical effect of optoelectronic functional coating materials is usually characterized by measuring photoinduced current density. For example, Chinese patent application CN114250473A, entitled "Iron Oxide-based Z-type Heterojunction Composite Photoanode Film and its Preparation Method and Application," describes a Fe2O3-CuInS2 composite photoanode film obtained by calcining a photoanode material. Its photoinduced open-circuit potential (OCP) is measured under intermittent illumination to determine its photoelectric performance. This photoelectrochemical effect is determined by the difference between the current densities under dark and illuminated conditions. However, this method has some inherent drawbacks. Existing photopolarization curves compare current values ​​under dark and illuminated conditions at the same bias voltage to determine the photoelectrochemical effect of the coating material. However, in reality, if the same bias voltage (relative to the reference electrode) is used, the degree to which this bias voltage deviates from the equilibrium potential under dark and illuminated conditions is inconsistent, affecting the accuracy of analyzing the photoelectrochemical effect of optoelectronic functional coating materials and making quantitative analysis difficult. Therefore, it is necessary to introduce a new analytical method for photoelectrochemical performance, which can intuitively characterize the actual photocurrent density of photoelectrochemical functional coatings and quantitatively analyze their electrochemical performance. Summary of the Invention

[0003] The purpose of this invention is to propose a method for quantitative analysis of photoelectrochemical performance based on polarization potential calibration, which can intuitively characterize the actual photocurrent density of photoelectrochemical functional coatings and quantitatively analyze their electrochemical performance.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] A method for quantitative analysis of photoelectrochemical performance based on polarization potential calibration includes the following steps:

[0006] (1) In a solution environment and under illumination, in a three-electrode system, the photoinduced OCP of the semiconductor electrode with photoelectric functional coating was tested, and the photoinduced polarization curve of the semiconductor electrode was obtained.

[0007] (2) In a solution environment and in the dark, in a three-electrode system, the dark-state OCP of the semiconductor electrode was tested, and the dark-state polarization curve of the semiconductor electrode was obtained.

[0008] (3) Based on the photo-polarization curve and the dark-state polarization curve, the semi-logarithmic polarization curve, the current density-potential curve, the ΔE-i curve and the ΔE-Δi curve are obtained;

[0009] (4) Analyze the photoelectrochemical performance of the semiconductor electrode based on the semi-logarithmic polarization curve, ΔE-i curve and ΔE-Δi curve obtained in step (3).

[0010] Furthermore, in step (1), when obtaining the photopolarization curve of the semiconductor electrode, the test potential range is ±200mV of the photoinduced OCP value of the semiconductor electrode, and the scan speed is 1.66mV / s.

[0011] In step (2), when obtaining the dark polarization curve of the semiconductor electrode, the test potential range is ±200mV of the dark state OCP value of the semiconductor electrode, and the scan speed is 1.66mV / s.

[0012] Furthermore, in step (3), the photopolarization curve and the dark polarization curve are combined into the same graph to obtain the semi-logarithmic polarization curve and the current density-potential curve, respectively.

[0013] Furthermore, in step (3), the test potential when the photo-polarization curve of the semiconductor electrode is obtained is subtracted from the corresponding photo-induced OCP to obtain the polarization potential ΔE. The photo-induced ΔE-i curve is obtained based on the polarization potential ΔE and the photo-induced polarization curve of the semiconductor electrode.

[0014] Subtract the corresponding dark-state OCP from the test potential when the dark-state polarization curve of the semiconductor electrode is obtained to get the polarization potential ΔE. Based on the polarization potential ΔE and the dark-state polarization curve of the semiconductor electrode, the dark-state ΔE-i curve is obtained.

[0015] The photoinduced ΔE-i curve and the dark-state ΔE-i curve are combined into the same graph to obtain the aforementioned ΔE-i curve.

[0016] Furthermore, in step (3), under the same polarization potential ΔE, the current density of the photo-polarized curve is subtracted from the current density of the dark-state polarization curve to obtain Δi, and the ΔE-Δi curve is obtained based on the polarization potential ΔE and Δi.

[0017] Furthermore, in step (4), by judging whether the potential of the photopolarization curve has shifted compared with the dark polarization curve, it is analyzed whether the illumination affects the photoelectrochemical reaction process of the semiconductor electrode.

[0018] The difference in current density caused by the photoelectrochemical performance of the semiconductor electrode was analyzed using the ΔE-i curve;

[0019] The photoelectrochemical performance of the semiconductor electrode at different polarization potentials was analyzed using the ΔE-Δi curves, and / or the effect of light radiation on the photoelectrochemical reaction process was analyzed.

[0020] Furthermore, in the three-electrode system of steps (1) and (2), the semiconductor electrode is used as the working electrode, the Ag / AgCl electrode is used as the reference electrode, and the Pt sheet electrode is used as the counter electrode.

[0021] Furthermore, the semiconductor electrode is made of conductive glass with a ZnO coating;

[0022] In steps (1) and (2), the solution environment is: a solution with a concentration of 0.25 mol L⁻¹ Na₂S and 0.35 mol L⁻¹ Na₂SO₃; and the light intensity is AM 1.5G. It is worth noting that the solution system and light intensity can be changed depending on the semiconductor electrode material.

[0023] The technical solution provided by this invention may include the following beneficial effects:

[0024] This invention first tests the photoinduced OCP (open-circuit potential) and dark-state OCP of the semiconductor electrode. Using the photoinduced OCP as a new reference zero point, the photoinduced polarization curve and dark-state polarization curve of the semiconductor electrode are obtained based on the photoinduced OCP and dark-state OCP. This ensures that the degree of deviation from the equilibrium potential is consistent, allowing for a direct characterization of the actual photoinduced current density of the photoelectric functional coating and quantitative analysis of its electrochemical performance. Furthermore, based on the photoinduced polarization curve and the dark-state polarization curve, the semi-logarithmic polarization curve, current density-potential curve, ΔE-i curve, and ΔE-Δi curve are derived. Analyzing these curves yields the photoelectrochemical performance and allows for quantitative analysis of the photoelectrochemical performance of the photoelectric functional coating on the semiconductor electrode. Attached Figure Description

[0025] Figure 1 This is a semi-logarithmic polarization curve under illumination / dark conditions according to an embodiment of the present invention;

[0026] Figure 2 This is a potential-current density curve under illumination / dark conditions according to an embodiment of the present invention;

[0027] Figure 3 This is a graph of ΔE-i under illumination / dark conditions according to an embodiment of the present invention.

[0028] Figure 4 This is a graph of ΔE-Δi under illumination / dark conditions according to an embodiment of the present invention. Detailed Implementation

[0029] This invention provides a method for quantitative analysis of photoelectrochemical performance based on polarization potential calibration, comprising the following steps:

[0030] (1) In a solution environment and under illumination, in a three-electrode system, the photoinduced OCP of the semiconductor electrode with photoelectric functional coating was tested, and the photoinduced polarization curve of the semiconductor electrode was obtained.

[0031] (2) In a solution environment and in the dark, in a three-electrode system, the dark-state OCP of the semiconductor electrode was tested, and the dark-state polarization curve of the semiconductor electrode was obtained.

[0032] (3) Based on the photo-polarization curve and the dark-state polarization curve, the semi-logarithmic polarization curve, the current density-potential curve, the ΔE-i curve and the ΔE-Δi curve are obtained;

[0033] (4) Analyze the photoelectrochemical performance of the semiconductor electrode based on the semi-logarithmic polarization curve, ΔE-i curve and ΔE-Δi curve obtained in step (3).

[0034] This invention first tests the photoinduced OCP (open-circuit potential) and dark-state OCP of the semiconductor electrode. Using the photoinduced OCP as a new reference zero point, the photoinduced polarization curve and dark-state polarization curve of the semiconductor electrode are obtained based on the photoinduced OCP and dark-state OCP. This ensures that the degree of deviation from the equilibrium potential is consistent, allowing for a direct characterization of the actual photoinduced current density of the photoelectric functional coating and quantitative analysis of its electrochemical performance. Furthermore, based on the photoinduced polarization curve and the dark-state polarization curve, the semi-logarithmic polarization curve, current density-potential curve, ΔE-i curve, and ΔE-Δi curve are derived. Analyzing these curves yields the photoelectrochemical performance and allows for quantitative analysis of the photoelectrochemical performance of the photoelectric functional coating on the semiconductor electrode.

[0035] Furthermore, in step (1), when obtaining the photopolarization curve of the semiconductor electrode, the test potential range is ±200mV of the photoinduced OCP value of the semiconductor electrode, and the scan speed is 1.66mV / s.

[0036] In step (2), when obtaining the dark polarization curve of the semiconductor electrode, the test potential range is ±200mV of the dark state OCP value of the semiconductor electrode, and the scan speed is 1.66mV / s.

[0037] In order to obtain the photopolarization curve, when testing in the test environment, the test potential is deviated from the photo-induced OCP or dark-state OCP. In order to reduce the influence of polarization on the physicochemical properties of the electrode surface, the deviation of the test potential from the photo-induced OCP or dark-state OCP is limited, and the scan speed is limited to 1.66mV / s to obtain a vertical line with reference significance.

[0038] Furthermore, in step (3), the photopolarization curve and the dark polarization curve are merged into the same graph to obtain a semi-logarithmic polarization curve and a current density-potential curve, respectively. The semi-logarithmic polarization curve can be obtained by converting the current coordinate values ​​of the photopolarization curve and the dark polarization curve. The photopolarization and dark polarization curves are then merged into the same graph without any changes, thus obtaining the current density-potential curve. Merging the photopolarization and dark polarization curves into the same graph makes curve analysis more convenient.

[0039] Furthermore, in step (3), the test potential when the photo-polarization curve of the semiconductor electrode is obtained is subtracted from the corresponding photo-induced OCP to obtain the polarization potential ΔE. The photo-induced ΔE-i curve is obtained based on the polarization potential ΔE and the photo-induced polarization curve of the semiconductor electrode.

[0040] Subtract the corresponding dark-state OCP from the test potential when the dark-state polarization curve of the semiconductor electrode is obtained to get the polarization potential ΔE. Based on the polarization potential ΔE and the dark-state polarization curve of the semiconductor electrode, the dark-state ΔE-i curve is obtained.

[0041] The photoinduced ΔE-i curve and the dark-state ΔE-i curve are combined into the same graph to obtain the aforementioned ΔE-i curve.

[0042] By combining the photo-induced ΔE-i curve and the dark-state ΔE-i curve into the same graph, the difference in current density caused by the photoelectrochemical performance of the semiconductor electrode can be clearly seen, making quantitative analysis more convenient.

[0043] Furthermore, in step (3), under the same polarization potential ΔE, the current density of the photo-polarized curve is subtracted from the current density of the dark-state polarization curve to obtain Δi, and the ΔE-Δi curve is obtained based on the polarization potential ΔE and Δi.

[0044] Furthermore, in step (4), by judging whether the potential of the photopolarization curve has shifted compared with the dark polarization curve, it is analyzed whether the illumination affects the photoelectrochemical reaction process of the semiconductor electrode.

[0045] The difference in current density caused by the photoelectrochemical performance of the semiconductor electrode was analyzed using the ΔE-i curve;

[0046] The photoelectrochemical performance of the semiconductor electrode at different polarization potentials was analyzed using the ΔE-Δi curves, and / or the effect of light radiation on the photoelectrochemical reaction process was analyzed.

[0047] Furthermore, in the three-electrode system of steps (1) and (2), the semiconductor electrode is used as the working electrode, the Ag / AgCl electrode as the reference electrode, and the Pt sheet electrode as the counter electrode. Using the Ag / AgCl electrode and the Pt sheet electrode makes it easier to obtain accurate test data, and these two electrodes have good chemical stability.

[0048] Furthermore, the semiconductor electrode is made of conductive glass with a ZnO coating; in steps (1) and (2), the solution environment is: a solution with a concentration of 0.25 mol L⁻¹ Na₂S and 0.35 mol L⁻¹ Na₂SO₃; and the light intensity is AM 1.5G. It is worth noting that the solution system and light intensity can be changed according to the different semiconductor electrode materials.

[0049] The invention will be further illustrated using a semiconductor electrode made of conductive glass with a ZnO coating as an example.

[0050] The semiconductor electrode is fabricated as follows: 3 mg of ZnO powder, 80 μL of deionized water, 15 μL of isopropanol, and 5 μL of Nafion 117 buffer solution are added to a mortar and ground for 30 minutes to obtain a uniform dispersion. This dispersion is then uniformly coated onto an FTO conductive glass surface (2*1 cm). 2 After natural drying, a semiconductor electrode is obtained.

[0051] The electrochemical performance of the above-mentioned semiconductor electrode light was quantitatively analyzed using the method of the present invention, and the steps are as follows:

[0052] (1) The solution environment is: concentration of 0.25 mol / L. -1 Na2S and 0.35 mol L -1 Na₂SO₃ solution; simulated light intensity AM 1.5G. The three-electrode system consisted of a semiconductor electrode as the working electrode, an Ag / AgCl electrode as the reference electrode, and a Pt sheet electrode as the counter electrode. First, the photoinduced OCP of the semiconductor electrode was tested, and then the photoinduced polarization curve of the semiconductor electrode was measured under this environment (see...). Figure 1 The test potential range is ±200mV of the photoinduced OCP value of the semiconductor electrode, and the scan speed is 1.66mV / s.

[0053] (2) The solution environment consisted of 0.25 mol L⁻¹ Na₂S and 0.35 mol L⁻¹ Na₂SO₃ solutions. The three-electrode system used a semiconductor electrode as the working electrode, an Ag / AgCl electrode as the reference electrode, and a Pt sheet electrode as the counter electrode. Under dark conditions, the dark-state OCP of the semiconductor electrode was first tested, and the dark-state polarization curve of the semiconductor electrode was then tested under this environment (see...). Figure 1The test potential range is ±200mV of the dark-state OCP value of the semiconductor electrode, and the scan speed is 1.66mV / s.

[0054] (3) Draw a curve graph

[0055] The semi-logarithmic polarization curve can be obtained by transforming the current coordinate values ​​of the photo-induced polarization curve and the dark-state polarization curve, and the photo-induced and dark-state curves can be merged into a single graph (see [reference]). Figure 1 In the figure, the photopolarization curve and the dark polarization curve are combined into one without modification, and the current coordinate values ​​are represented linearly to obtain the current density-potential curve (Ei curve) (see [reference]). Figure 2 );

[0056] Subtracting the corresponding photo-induced OCP from the test potential used to obtain the photo-induced polarization curve of the semiconductor electrode yields the polarization potential ΔE. Based on the polarization potential ΔE and the photo-induced polarization curve of the semiconductor electrode, the photo-induced ΔE-i curve is derived. Subtracting the corresponding dark-state OCP from the test potential used to obtain the dark-state polarization curve of the semiconductor electrode yields the polarization potential ΔE. Based on the polarization potential ΔE and the dark-state polarization curve of the semiconductor electrode, the dark-state ΔE-i curve is derived. The ΔE-i curve is obtained by merging the photo-induced ΔE-i curve and the dark-state ΔE-i curve into a single graph (see reference). Figure 3 ).

[0057] At the same polarization potential ΔE, the current density of the photopolarization curve is subtracted from the current density of the dark-state polarization curve to obtain Δi. Based on the polarization potentials ΔE and Δi, the ΔE-Δi curve is obtained (refer to...). Figure 4 ).

[0058] (4) Analyze the photoelectrochemical properties of the photoelectric functional coating based on the curve graph.

[0059] like Figure 1 As shown, by judging from the negative shift of the potential of the photopolarization curve compared with the dark polarization curve, it is indicated that the light irradiation affects the photoelectrochemical reaction process of the ZnO coating.

[0060] like Figure 2 As shown, the photoinduced Ei curve and the dark-state Ei curve do not overlap. The current value under illumination is greater than the current value under darkness throughout the entire potential study range. The photoelectrochemical performance is reflected by comparing the current values ​​under illumination and darkness under a uniform bias voltage.

[0061] like Figure 3 As shown, the intersection of the photoinduced ΔE-i curve and the dark-state ΔE-i curve coincides with the zero point of the coordinate axis. This zero point becomes the standard for distinguishing between the anode and cathode regions: at the negative bias at the zero point, it is the cathode region, where the dark current is greater than the photocurrent; at the positive bias at the zero point, it is the anode region, where the photocurrent is greater than the dark current. Therefore, unlike... Figure 2 Compared with traditional photoelectrochemical characterization methods, the ΔE-i curve of this method can effectively reflect the anode and cathode regions of the photoelectrochemical reaction, thus reflecting the photoelectrochemical process more accurately.

[0062] like Figure 4 As shown, the ΔE-Δi curve more intuitively displays the photoelectrochemical performance under different bias voltages. By analyzing the magnitude and direction of the current difference (Δi), the photoelectrochemical effects of the photoelectric material at different polarization potentials can be quantitatively assessed: a positive Δi indicates an anodic reaction, while a negative Δi indicates a cathodic reaction; the magnitude of Δi characterizes the reaction rate. Simultaneously, the degree and differences in the influence of light radiation on the anode and cathode processes can be quantitatively analyzed. A larger current density (Δi) value indicates that the photoelectrochemical reaction induced by light radiation is more readily carried out.

[0063] Other components and operations of the method for quantitative analysis of photoelectrochemical performance based on polarization potential calibration according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0064] In the description of this specification, references to terms such as "embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for quantitative analysis of photoelectrochemical performance based on polarization potential calibration, characterized in that, Includes the following steps: (1) In a solution environment and under light irradiation, the photoinduced OCP of the semiconductor electrode with photoelectric functional coating was tested in a three-electrode system, and the photoinduced polarization curve of the semiconductor electrode was obtained. (2) In a solution environment and in the dark, in a three-electrode system, the dark-state OCP of the semiconductor electrode was tested, and the dark-state polarization curve of the semiconductor electrode was obtained. (3) Based on the photo-polarization curve and the dark-state polarization curve, the semi-logarithmic polarization curve, the current density-potential curve, the ΔE-i curve and the ΔE-Δi curve are obtained; (4) Analyze the photoelectrochemical performance of the semiconductor electrode based on the semi-logarithmic polarization curve, ΔE-i curve and ΔE-Δi curve obtained in step (3); In step (3), the photopolarization curve and the dark polarization curve are combined into the same graph to obtain the semi-logarithmic polarization curve and the current density-potential curve, respectively. In step (3), the test potential when the photo-polarization curve of the semiconductor electrode is obtained is subtracted from the corresponding photo-induced OCP to obtain the polarization potential ΔE. The photo-induced ΔE-i curve is obtained based on the polarization potential ΔE and the photo-induced polarization curve of the semiconductor electrode. Subtract the corresponding dark-state OCP from the test potential when the dark-state polarization curve of the semiconductor electrode is obtained to get the polarization potential ΔE. Based on the polarization potential ΔE and the dark-state polarization curve of the semiconductor electrode, the dark-state ΔE-i curve is obtained. The photoinduced ΔE-i curve and the dark-state ΔE-i curve are combined into the same figure to obtain the ΔE-i curve mentioned above. In step (3), under the same polarization potential ΔE, the current density of the photo-polarized curve is subtracted from the current density of the dark-state polarization curve to obtain Δi, and the ΔE-Δi curve is obtained based on the polarization potential ΔE and Δi. In step (4), by judging whether the potential of the photopolarization curve has shifted compared with the dark polarization curve, it is analyzed whether the illumination affects the photoelectrochemical reaction process of the semiconductor electrode. The difference in current density caused by the photoelectrochemical performance of the semiconductor electrode was analyzed using the ΔE-i curve; The photoelectrochemical performance of the semiconductor electrode under different polarization potentials was analyzed using the ΔE-Δi curves, and / or the influence of light radiation on the photoelectrochemical reaction process was analyzed. Wherein, OCP is the open circuit potential.

2. The method for quantitative analysis of photoelectrochemical performance based on polarization potential calibration according to claim 1, characterized in that, In step (1), when obtaining the photopolarization curve of the semiconductor electrode, the test potential range is ±200 mV of the photoinduced OCP value of the semiconductor electrode, and the scan speed is 1.66 mV / s. In step (2), when obtaining the dark polarization curve of the semiconductor electrode, the test potential range is ±200 mV of the dark state OCP value of the semiconductor electrode, and the scan speed is 1.66 mV / s.

3. The method for quantitative analysis of photoelectrochemical performance based on polarization potential calibration according to claim 1, characterized in that, In the three-electrode system of steps (1) and (2), the semiconductor electrode is used as the working electrode, the Ag / AgCl electrode is used as the reference electrode, and the Pt sheet electrode is used as the counter electrode.

4. The method for quantitative analysis of photoelectrochemical performance based on polarization potential calibration according to claim 1, characterized in that, The semiconductor electrode is made of conductive glass with a ZnO coating; In steps (1) and (2), the solution environment is: a solution with a concentration of 0.25 mol L-1 Na2S and 0.35 mol L-1 Na2SO3; and a light intensity of AM 1.5G.

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