Method for measuring electroactive area of three-dimensional porous membrane electrode

Abstract

The invention provides a method for measuring the electroactive area of a three-dimensional porous membrane electrode, which comprises the steps of: respectively measuring cyclic voltammetry curves under different scanning speeds in potassium cyanide-containing and potassium cyanide-free kali salt or sodium salt solution with a three-electrode system and a potentiostat by taking a three-dimensional porous electrode or the three-dimensional porous membrane electrode which is deposited with a transition element ferricyanide semiconductor membrane, and measuring the electroactive area and the cover degree thereof with the reversibility of the redox reaction of the membrane electrode in different solution systems; and obtaining the active volume and the average membrane depth of the inner membrane of the three-dimensional porous membrane electrode by combining with the chronocoulometry. The method is simple and reliable, and has strong practicability.

Description

technical field

[0001] The invention belongs to a method for measuring the electroactive area of ​​a three-dimensional porous membrane electrode, specifically, an electrochemical method for measuring the electroactive area of ​​a three-dimensional porous membrane electrode and the thickness of an active film. Background technique

[0002] The three-dimensional porous electrode can achieve high apparent current density and high macroscopic reaction rate by utilizing a large electrode active inner surface under relatively low electrode polarization. Due to a series of advantages such as large reaction surface area, good adsorption and mass transfer conditions, and long liquid-solid phase contact reaction time, three-dimensional porous electrodes are widely used in high-energy batteries, supercapacitors, fuel cells, electrodeposition, electrochemical synthesis, and electrocatalytic oxidation. This area of ​​technology has great application potential and its importance is increa...

Examples

Embodiment 1

[0032] A three-dimensional porous nickel foam matrix with a length, width and thickness of 1 cm, 1 cm and 0.12 cm was used as the working electrode, and at 5 mmol L -1 K 3 Fe(CN) 6 solution (which contains 0.5mol·L -1 Na 2 SO 4 as a supporting electrolyte) to measure the cyclic voltammetry curves at different scan speeds. Scan speeds are 10, 20, 30, 40, 50, 70, 100 and 200mV·s -1 . The peak current increases with the increase of the scanning speed, and the square root of the peak current and the scanning speed shows a good linear relationship, according to the Randles-Sevick formula into [Fe(CN) 6 ] 3- The concentration c(5m mol·L -1 ) and its diffusion coefficient D(6.2×10 -6 cm 2 ·s -1 ), by the slope B of the line (101.032×10 -3 ) Calculate the electrochemical reaction active area A of the membrane electrode to be 30.168cm 2 .

[0033] Electrodeposition method was used to deposit NiHCF thin film on the nickel foam electrode, and the three-dimensional porous me...

Embodiment 2

[0035] 18 graphite cores with a diameter of 2mm were divided into three rows and assembled into a multi-row graphite core matrix as a working electrode. -1 K 3 Fe(CN) 6 solution (which contains 0.5mol·L -1 Na 2 SO 4 as a supporting electrolyte) to measure the cyclic voltammetry curves at different scan speeds. Scan speeds are 10, 20, 30, 40, 50, 70, 100 and 200mV·s -1 . The peak current increases with the increase of the scanning speed, and the square root of the peak current and the scanning speed shows a good linear relationship, according to the Randles-Sevick formula into [Fe(CN) 6 ] 3- The concentration c(5m mol·L -1 ) and its diffusion coefficient D(6.2×10 -6 cm 2 ·s -1 ), by the slope B of the line (57.421×10 -3 ) Calculate the electrochemical reaction area A of the electrode as 42.296cm 2 , and the theoretical surface area of ​​the graphite matrix is ​​50.87cm 2 very close.

[0036] Electrodeposition method was used to deposit NiHCF thin film on this mul...

Embodiment 3

[0039] Graphite particles with a particle size of 50-300 μm are added to an appropriate amount of polytetrafluoroethylene and ethanol, thoroughly stirred, and then coated layer by layer on a nickel mesh with a length × width of 1 cm × 1 cm. After drying, it is compressed into a three-dimensional porous conductive material. substrate; then the three-dimensional porous NiHCF membrane electrode is prepared by chemical deposition method. at 1mol L -1 KNO 3 The cyclic voltammetry curves at different scan speeds were measured in the solution. Scan speeds are 10, 20, 30, 40, 50, 70, 100 and 200mV·s -1 . The peak current increases with the increase of the scanning speed, and the square root of the peak current and the scanning speed shows a good linear relationship, and the electrochemical reaction active area A of the membrane electrode is calculated from the slope of the straight line ac 0.32cm 2 .

[0040] The porous graphite-based NiHCF membrane electrode was used as the wor...

technical field

[0001] The invention belongs to a method for measuring the electroactive area of ​​a three-dimensional porous membrane electrode, specifically, an electrochemical method for measuring the electroactive area of ​​a three-dimensional porous membrane electrode and the thickness of an active film. Background technique

[0002] The three-dimensional porous electrode can achieve high apparent current density and high macroscopic reaction rate by utilizing a large electrode active inner surface under relatively low electrode polarization. Due to a series of advantages such as large reaction surface area, good adsorption and mass transfer conditions, and long liquid-solid phase contact reaction time, three-dimensional porous electrodes are widely used in high-energy batteries, supercapacitors, fuel cells, electrodeposition, electrochemical synthesis, and electrocatalytic oxidation. This area of ​​technology has great application potential and its importance is increa...

Examples

Embodiment 1

[0032] A three-dimensional porous nickel foam matrix with a length, width and thickness of 1 cm, 1 cm and 0.12 cm was used as the working electrode, and at 5 mmol L -1 K 3 Fe(CN) 6 solution (which contains 0.5mol·L -1 Na 2 SO 4 as a supporting electrolyte) to measure the cyclic voltammetry curves at different scan speeds. Scan speeds are 10, 20, 30, 40, 50, 70, 100 and 200mV·s -1 . The peak current increases with the increase of the scanning speed, and the square root of the peak current and the scanning speed shows a good linear relationship, according to the Randles-Sevick formula into [Fe(CN) 6 ] 3- The concentration c(5m mol·L -1 ) and its diffusion coefficient D(6.2×10 -6 cm 2 ·s -1 ), by the slope B of the line (101.032×10 -3 ) Calculate the electrochemical reaction active area A of the membrane electrode to be 30.168cm 2 .

[0033] Electrodeposition method was used to deposit NiHCF thin film on the nickel foam electrode, and the three-dimensional porous me...

Embodiment 2

[0035] 18 graphite cores with a diameter of 2mm were divided into three rows and assembled into a multi-row graphite core matrix as a working electrode. -1 K 3 Fe(CN) 6 solution (which contains 0.5mol·L -1 Na 2 SO 4 as a supporting electrolyte) to measure the cyclic voltammetry curves at different scan speeds. Scan speeds are 10, 20, 30, 40, 50, 70, 100 and 200mV·s -1 . The peak current increases with the increase of the scanning speed, and the square root of the peak current and the scanning speed shows a good linear relationship, according to the Randles-Sevick formula into [Fe(CN) 6 ] 3- The concentration c(5m mol·L -1 ) and its diffusion coefficient D(6.2×10 -6 cm 2 ·s -1 ), by the slope B of the line (57.421×10 -3 ) Calculate the electrochemical reaction area A of the electrode as 42.296cm 2 , and the theoretical surface area of ​​the graphite matrix is ​​50.87cm 2 very close.

[0036] Electrodeposition method was used to deposit NiHCF thin film on this mul...

Embodiment 3

[0039] Graphite particles with a particle size of 50-300 μm are added to an appropriate amount of polytetrafluoroethylene and ethanol, thoroughly stirred, and then coated layer by layer on a nickel mesh with a length × width of 1 cm × 1 cm. After drying, it is compressed into a three-dimensional porous conductive material. substrate; then the three-dimensional porous NiHCF membrane electrode is prepared by chemical deposition method. at 1mol L -1 KNO 3 The cyclic voltammetry curves at different scan speeds were measured in the solution. Scan speeds are 10, 20, 30, 40, 50, 70, 100 and 200mV·s -1 . The peak current increases with the increase of the scanning speed, and the square root of the peak current and the scanning speed shows a good linear relationship, and the electrochemical reaction active area A of the membrane electrode is calculated from the slope of the straight line ac 0.32cm 2 .

[0040] The porous graphite-based NiHCF membrane electrode was used as the wor...

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