CN-122016973-A - Electrochemical flexible carbon monoxide gas sensor based on composite hydrogel

CN122016973ACN 122016973 ACN122016973 ACN 122016973ACN-122016973-A

Abstract

The invention discloses an electrochemical flexible carbon monoxide gas sensor based on composite hydrogel, which takes a composite hydrogel proton exchange membrane as an intermediate layer, wherein flexible electrode layers are fixed on the upper surface and the lower surface of the composite hydrogel proton exchange membrane through adhesives, the outside of an electrode is encapsulated by a PDMS encapsulation layer, the composite hydrogel proton exchange membrane is a gel film, the flexible electrode layer adopts carbon paper loaded with a noble metal catalyst and is combined on the upper surface and the lower surface of the composite hydrogel proton exchange membrane through chain winding and high polymer plasticization, so that tight entanglement is formed between the flexible electrode layer and the proton exchange membrane, and the PDMS encapsulation layer is doped with carbon black and has the surface super-hydrophobic property. The electrochemical flexible carbon monoxide gas sensor prepared by the invention can rapidly respond to medium-low concentration carbon monoxide, can be carried on wearable equipment to realize safety monitoring, and has good application prospect.

Inventors

GE YITAO
LIU JIAN
TANG XINYUE
ZHOU YA
WANG YAN
LIU PING
YU LINYI
HUANG TIEHAO
Ye Hanzhen
SUN XUEQING
GE ZHENGYUAN
TENG FEI
WANG ZHENTI
YING ZHIFU

Assignees

合肥工业大学
国网安徽省电力有限公司滁州供电公司

Dates

Publication Date: 20260512
Application Date: 20260330

Claims (8)

1. The electrochemical flexible carbon monoxide gas sensor based on the composite hydrogel is characterized by being of a multilayer symmetrical composite structure, and sequentially comprising a PDMS packaging layer, a flexible carbon paper working electrode, a composite hydrogel proton exchange membrane, a flexible carbon paper counter electrode and a PDMS packaging layer from top to bottom; The composite hydrogel proton exchange membrane is prepared by directional freezing and casting pre-structuring treatment, room temperature solidification, salting out with saturated sodium citrate solution and deionized water cleaning and wetting of a composite hydrogel solution, wherein the total mass fraction of chitosan, sulfonic group modified sodium alginate, polyglutamic acid, lysine, diethylene glycol and acetic acid in the composite hydrogel solution is 2.4-3.4%, and the solvent of the composite hydrogel solution is deionized water; The composite hydrogel proton exchange membrane and the flexible carbon paper working electrode and the composite hydrogel proton exchange membrane and the flexible carbon paper counter electrode are all adhered and fixed through a tannic acid-polyvinyl alcohol adhesive; the flexible carbon paper working electrode and the flexible carbon paper counter electrode have the same structure, carbon paper is used as a base material, and a Pt/Au bimetallic catalyst is loaded on the surface of the base material; the PDMS packaging layer is prepared by spraying, crosslinking and shaping a PDMS suspension doped with carbon black.
2. The electrochemical flexible carbon monoxide gas sensor based on the composite hydrogel according to claim 1, wherein the mass ratio of chitosan, sulfonic group modified sodium alginate, polyglutamic acid, lysine, diethylene glycol and acetic acid in the composite hydrogel solution is 3:5-8:1-1.5:0.25-0.5:2-3:1.2-1.6, and the molecular weight of polyglutamic acid is 50000-100000.
3. The electrochemical flexible carbon monoxide gas sensor based on the composite hydrogel, which is disclosed in claim 1 or 2, is characterized in that sodium alginate is dissolved in 0.1mol/L MES buffer solution to prepare sodium alginate solution with the mass fraction of 1-2%, taurine solid is added into the sodium alginate solution according to the mass ratio of 0.1mol/L MES buffer solution to 0.4-0.6, after the sodium alginate solution is stirred until the sodium alginate is completely dissolved, EDC and HCl/NHS mixed solution is added dropwise, stirring is carried out at room temperature under the dark condition for 12-24 hours, after the reaction is finished, the reaction solution is poured into ice-precooled absolute ethyl alcohol to precipitate, the precipitate is collected by centrifugation and re-dissolved in deionized water, and after dialysis for 72-84 hours by a dialysis bag with the molecular weight of 12000-14000 daltons, the sodium alginate solution is frozen and dried to obtain the sulfonic acid modified sodium alginate, wherein the EDC and HCl/NHS mixed solution is prepared by taking 0.1mol/L MES buffer solution as a solvent, and the concentration of EDC and HCl/NHS mixed solution is 0.05mol/L, and the mass ratio of EDC and NHS mixed solution to 3.080.088:0.3-3.051 to 0.088.
4. The electrochemical flexible carbon monoxide gas sensor based on the composite hydrogel according to claim 1, wherein the Pt/Au bimetallic catalyst on the surfaces of the flexible carbon paper working electrode and the flexible carbon paper counter electrode is supported on the surface of the carbon paper substrate by a halogen-regulated metal in-situ growth method with KBr as a halogen regulator and ascorbic acid as a reducing agent.
5. The sensor of claim 4, wherein the Pt/Au bimetallic catalyst is prepared by the steps of: Dissolving H 2 PtCl 6 ·6H 2 O in deionized water to obtain a solution, adding KBr, stirring and dissolving to obtain a first mixed solution with the molar ratio of KBr to H 2 PtCl 6 ·6H 2 O of 10-12:1, immersing carbon paper in the first mixed solution for reaction for 20-30 minutes, dropwise adding an ascorbic acid solution with the molar ratio of ascorbic acid to H 2 PtCl 6 ·6H 2 O of 12-18:1, stirring for 4-6 hours at 40 ℃, washing and drying to obtain Pt-loaded carbon paper; Dissolving HAuCl 4 ·3H 2 O in deionized water to obtain a solution, adding KBr, stirring and dissolving to obtain a second mixed solution with the molar ratio of KBr to HAuCl 4 ·3H 2 O of 10-12:1, immersing carbon paper loaded with Pt into the second mixed solution for reaction for 20-30 minutes, dripping an ascorbic acid solution with the molar ratio of ascorbic acid to HAuCl 4 ·3H 2 O of 12-18:1, stirring for 0.5-2 hours at 40 ℃, washing and drying to obtain the flexible carbon paper electrode loaded with the Pt/Au bimetallic catalyst, and taking the flexible carbon paper electrode as a flexible carbon paper working electrode and a flexible carbon paper counter electrode.
6. The sensor of claim 1, wherein the tannic acid-polyvinyl alcohol binder is prepared by mixing polyvinyl alcohol, tannic acid and deionized water in a dosage ratio of 1 g:0.8-1 g:20: 20 mL.
7. The sensor of claim 1, wherein the mass ratio of carbon black to PDMS mixture in the carbon black doped PDMS suspension is 0.4-0.6:1.
8. A method for preparing the electrochemical flexible carbon monoxide gas sensor based on the composite hydrogel according to any one of claims 1 to 7, which is characterized by comprising the following steps: step 1, preparing a composite hydrogel proton exchange membrane Dissolving chitosan in acetic acid solution with the mass fraction of 1%, stirring until the chitosan is completely dissolved to obtain chitosan acetic acid solution, dissolving sulfonic modified sodium alginate in deionized water, stirring until the solution is transparent to obtain sulfonic modified sodium alginate solution, dissolving polyglutamic acid in deionized water to obtain polyglutamic acid solution, mixing the chitosan acetic acid solution, the sulfonic modified sodium alginate solution and the polyglutamic acid solution, stirring for 1 hour, adding lysine and diethylene glycol, continuously stirring for 2-4 hours to form uniform composite hydrogel solution, filling the composite hydrogel solution into a brass-polytetrafluoroethylene mold, freezing for 12-24 hours at-20 to-40 ℃, thawing for 4-8 hours at 4-25 ℃, repeating the freezing-thawing cycle for 2-4 times to complete directional freezing-thawing pre-structuring treatment, filling the pre-structured composite hydrogel solution into the polytetrafluoroethylene mold, curing at room temperature, soaking and salting out for 5-10 minutes at room temperature through saturated sodium citrate solution, and washing and wetting with deionized water to obtain the composite hydrogel proton exchange membrane; Step 2, preparing the flexible carbon paper electrode Using KBr as a halogen regulator and ascorbic acid as a reducing agent, and loading a Pt/Au bimetallic catalyst on the surface of a carbon paper substrate by a halogen-regulated metal in-situ growth method to prepare a flexible carbon paper working electrode and a flexible carbon paper counter electrode; step 3, preparing tannin-polyvinyl alcohol adhesive Dissolving polyvinyl alcohol powder in deionized water, heating and stirring at 80-85 ℃ until the polyvinyl alcohol powder is completely dissolved, cooling to room temperature, adding tannic acid powder, and continuously stirring until tannic acid is completely dissolved to obtain a tannic acid-polyvinyl alcohol adhesive, wherein the dosage ratio of polyvinyl alcohol, tannic acid and deionized water is1 g:0.8-1 g:20 mL; step 4, preparing a PDMS suspension doped with carbon black Mixing a main agent and a curing agent in a PDMS mixture with a mass ratio of 10:1 according to a volume ratio of PDMS mixture to normal hexane to deionized water=10:6-6.5:50-55, and vigorously stirring to form a PDMS solution, adding carbon black into the PDMS solution, wherein the mass ratio of the carbon black to the PDMS mixture is 0.4-0.6:1, uniformly stirring, and diluting the mixture with deionized water until the mass fraction of the system is 1-2%, thus obtaining a PDMS suspension doped with the carbon black; Step 5, assembling the sensor And (2) respectively washing the working electrode of the flexible carbon paper and the counter electrode of the flexible carbon paper by acetone, ethanol and deionized water in sequence, drying at normal temperature, then placing the dried carbon black-doped PDMS suspension prepared in the step (4) in a heating environment of 70-80 ℃, spraying the carbon black-doped PDMS suspension for the next time after each time of standing and drying, spraying for 3-4 times, respectively treating the two electrodes at 70-80 ℃ for 1-2 hours after the spraying is finished to obtain a working electrode-PDMS packaging layer combination and a counter electrode-PDMS packaging layer combination, respectively washing and drying the two combinations again, respectively spin-coating tannic acid-polyvinyl alcohol adhesive on one side of the carbon paper electrode of each combination for two times, air-drying at room temperature until touch drying is finished to pre-cure after the first spin-coating, bonding the composite hydrogel proton exchange membrane prepared in the step (1) between bonding interfaces of the two electrodes after the second spin-coating, removing internal bubbles, and curing at room temperature for 4-6 hours under a compacting state to obtain the electrochemical flexible carbon monoxide gas sensor based on the composite hydrogel.

Description

Electrochemical flexible carbon monoxide gas sensor based on composite hydrogel Technical Field The invention belongs to the field of sensors, and particularly relates to an electrochemical flexible carbon monoxide gas sensor based on composite hydrogel. Background Carbon monoxide (CO) is colorless, odorless and highly toxic gas, and widely exists in scenes such as industrial production, mine operation, civil gas leakage and the like, and seriously threatens the life safety of human bodies. Therefore, development of a carbon monoxide sensor with rapid response, miniaturization, flexibility and high reliability is a core requirement for guaranteeing public safety and industrial safety production. In recent years, the development of a miniaturized and flexible carbon monoxide sensor is focused, and the core reason is that the traditional sensor has a plurality of defects generally, so that the application of the sensor in actual combat safety monitoring scenes such as wearable equipment, miner carry-on alarms and the like is severely limited, the scenes have extremely high requirements on equipment portability and environmental adaptability, and the sensor is required to have quick response capability so as to ensure that personnel evacuate in time. According to the working principle, the existing carbon monoxide sensor is mainly divided into five categories of optical infrared type, metal oxide type, catalytic combustion type, carbon adsorption type and electrochemical type, a great deal of research and industrialization practice are developed around various sensor performance optimization in the industry, various technologies are developed to a certain extent, and specific research results are as follows: an NDIR carbon monoxide infrared sensing module developed by trace gas sensing technology has the characteristics of quick response (T90 is less than or equal to 200 ms), range coverage of 0-3000 ppm, accuracy is less than or equal to +/-1% FS, repeatability is less than or equal to +/-1% FS, the application range of working temperature is 0-45 ℃, and the whole detection performance is excellent. The invention discloses a room temperature MEMS carbon monoxide sensor based on Nb-TiO 2/WO3 mass-bonded powder material, which is prepared by synthesizing porous In 2O3 nanorods by a hydrothermal method with low cost and simple operation, wherein a response value of the metal oxide type carbon monoxide sensor prepared by heat treatment to 400ppm carbon monoxide reaches 3.5 at the working temperature of 350 ℃ and has good selectivity and stability to carbon monoxide, and the invention patent with publication number CN120651924A provides a room temperature MEMS carbon monoxide sensor based on Nb-TiO 2/WO3 mass-bonded powder material, improves the sensitivity and selectivity of TiO 2 to carbon monoxide by Nb doping and WO 3 modification, and combines the characteristics of miniaturization, easy integration, small power consumption and good stability of MEMS devices. Catalytic combustion formula Huang Caixia in its' Shuoshi paper (catalytic combustion type carbon monoxide sensor based on tricobalt tetraoxide [ D ]. Nanjing university of industry, 2013.) it was proposed to prepare catalytic combustion type carbon monoxide sensor from Pt and Co 3O4, wherein the sensitivity of the Pt-based sensor is up to 2.67V.L.mg -1, the detection limit is as low as 0.0035 mg/L, the sensitivity of the Co 3O4 -based sensor is up to 1.04V.L.mg -1, the detection limit is 0.013 mg/L, and both sensors have good long-term stability. Carbon adsorption Zuo J et al (Zuo J, et al Chemosensors, 2020, 8 (2): 36) shows for the first time a printed flexible carbon monoxide sensor array fabrication scheme based on printable semiconductor catalyst decorated reduced graphene oxide sensor media that can be run at room temperature and deposited on thin flexible substrates using high throughput printing and coating methods with the potential for flexible, scalable fabrication. The electrochemical type sensor has the advantages of simple structure and easy miniaturization as the technical route with the best wearable scene adaptation potential at present, partial products have realized performance breakthrough, namely a carbon monoxide sensor based on MECS (micro electrochemical System) technology developed by Ministry of electronic technology, which has the weight of only about 0.19g, the volume of about 0.1cm 3, the linear range of 0-500 ppm, the sensitivity of >1 nA/ppm, the response time T of 90<20 seconds, zero response in 2000 ppm alcohol interference environment and excellent anti-interference capability, and the research project of Nafion proton membrane-based fuel cell type CO sensor which is mainly used by Jilin university Songhui, which is optimized from the two aspects of sensor structural design and membrane electrode material preparation process, widens the detection concentration range of the sensor to 0.1-500 ppm, improves the sensitivity