Composite carbon-based electrothermal coating thermal catalytic indoor air purification wall and its construction method

Abstract

The present invention relates to the field of building integrated photovoltaics, and particularly to a composite carbon - based electrothermal coating thermal - catalytic indoor air - purifying wall and its construction method. The wall from outside to inside comprises a solar photovoltaic cell, a building wall and an air - purifying unit. The air - purifying unit includes a heat - insulating and adiabatic backboard, a coating substrate, a conductive unit, a composite carbon - based electrothermal coating and a MnO x -CeO2 thermal - catalytic coating. The heat - insulating and adiabatic backboard is arranged in contact with the building wall. The coating substrate is arranged on the side of the heat - insulating and adiabatic backboard away from the building wall. The composite carbon - based electrothermal coating is arranged on the surface of the coating substrate. The conductive unit is arranged at both ends of the coating substrate and is connected to the solar photovoltaic cell through wires. MnO x -CeO2 thermal - catalytic coating is arranged on the composite carbon - based electrothermal coating to catalyze and purify indoor air. The present invention drives the MnO x -CeO2 thermal - catalytic coating to purify indoor pollutants through the heat of the composite carbon - based electrothermal coating, realizing simultaneous heating and air purification, and providing a method for removing pollutants when indoor ventilation cannot be carried out for a long time in winter.

Description

Technical Field

[0001] The present invention relates to the field of building integrated photovoltaics, and particularly to a composite carbon-based electrothermal coating thermal catalytic indoor air purification wall and its construction method. Background Art

[0002] With the continuous improvement of China's comprehensive national strength, people's housing conditions have been gradually improved, and there are various decoration materials on the market. However, the pollution brought by these decoration materials has become more and more serious, posing a great potential threat to people's health. Such as eye and skin allergies, and even causing serious hazards such as teratogenesis, mutagenesis and carcinogenesis; since more than 80% of a person's life is spent indoors, and the elderly and infants may spend up to 95% of their time indoors, the hazards of indoor pollutants affect a large number of people and have a wide range of hazards, gradually attracting extensive attention from society. How to effectively control indoor air pollution is of great significance to people's health and the improvement of people's quality of life.

[0003] Common indoor polluting gases include formaldehyde, toluene, polycyclic aromatic hydrocarbons, CO, etc. In the prior art, the conventional treatment method of ventilation can disperse indoor pollutants, but it can only treat some pollutants emitted by furniture, which is a method that treats the symptoms rather than the root cause. And in winter with low temperatures, it is difficult to achieve indoor heating by opening windows for ventilation. Therefore, how to develop a green, non-toxic and non-secondary pollution treatment method that can meet the functions of heating and air purification simultaneously and provide an effective measure for removing pollutants when indoor ventilation cannot be carried out for a long time in winter is a technical problem that needs to be solved urgently. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: to propose a composite carbon-based electrothermal coating thermal catalytic indoor air purification wall that can achieve the functions of heating and air purification simultaneously during the winter heating season.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A composite carbon-based electrothermal coating thermal catalytic indoor air purification wall, the wall from outside to inside is successively a solar photovoltaic cell, a building wall and an air purification unit, and the solar photovoltaic cell is connected to the air purification unit through a wire;

[0007] The air purification unit includes a thermal insulation backboard, a coating substrate, a conductive unit, a composite carbon-based electrothermal coating and a MnO x -CeO2 thermal catalytic coating, the thermal insulation backboard is arranged in contact with the building wall, the coating substrate is arranged on the side of the thermal insulation backboard away from the building wall, and the composite carbon-based electrothermal coating is arranged on the surface of the coating substrate; the conductive unit is arranged at both ends of the coating substrate and is connected to the solar photovoltaic cell through a wire; MnO xThe -CeO2 thermal catalytic coating is disposed on the composite carbon-based electrothermal coating to catalyze and purify indoor air.

[0008] Furthermore, the conductive unit includes a wiring terminal and a conductive copper strip. The conductive copper strip is disposed at both ends of the coating substrate and is connected to the composite carbon-based electrothermal coating; the wiring terminal is disposed on the conductive copper strip and is connected to the solar photovoltaic cell through a wire.

[0009] Furthermore, the conductive unit further includes an insulating heat shrink sleeve, which is disposed on the outer surfaces of the conductive copper strip and the wiring terminal.

[0010] Furthermore, the solar photovoltaic cell is fixed to the outer side of the building wall through a support frame.

[0011] Furthermore, a temperature control valve is disposed between the solar photovoltaic cell and the air purification unit. The output end of the temperature control valve is connected to the conductive unit and an external storage battery. The temperature control valve senses the temperature and automatically adjusts the path between the solar photovoltaic cell, the conductive unit, and the external storage battery.

[0012] Furthermore, the temperature control valve is provided with a first threshold and a second threshold, and the second threshold is greater than the first threshold;

[0013] When the temperature is lower than the first threshold, the output end of the solar photovoltaic cell and the output end of the external storage battery are respectively connected to the conductive unit; under the action of solar radiation, while the conductive unit generates electricity, the temperature of the composite carbon-based electrothermal coating rises, and the thermal catalytic layer is heated. At the same time, the external storage battery provides power for the conductive unit to ensure the thermal catalytic effect.

[0014] When the temperature is between the first threshold and the second threshold, the external storage battery is disconnected from the conductive unit;

[0015] When the temperature is higher than the second threshold, the output end of the solar photovoltaic cell is connected to the external storage battery.

[0016] Furthermore, the coating thickness of the composite carbon-based electrothermal coating is 0.1 - 0.3 mm, and the coating thickness of the MnO x -CeO2 thermal catalytic coating is 0.1 - 0.3 mm. The total thickness of the composite carbon-based electrothermal coating and the MnO x -CeO2 thermal catalytic coating does not exceed 0.4 - 0.5 mm.

[0017] Furthermore, a voltage regulator is also disposed between the solar photovoltaic cell and the conductive unit.

[0018] The second object of the present invention is to provide a construction method for a thermally catalytic indoor air purification wall with a composite carbon-based electrothermal coating, by preparing a composite carbon-based electrothermal material and a thermal catalyst MnO x -CeO2 powder, and obtaining a composite carbon-based electrothermal coating and MnO x -CeO2 thermally catalytic coating through coating, and using the solar photovoltaic and building integration technology to drive the composite carbon-based electrothermal coating by solar energy to solve the problem that pollutants cannot be removed by long-term ventilation indoors in winter.

[0019] A construction method for a thermally catalytic indoor air purification wall with a composite carbon-based electrothermal coating, characterized by comprising the following operating steps:

[0020] S01: Fix the solar photovoltaic cell on the outer side of the building wall using a support frame;

[0021] S02: Arrange the thermal insulation backboard on the inner surface of the building wall;

[0022] S03: Fix and connect the coating substrate to the thermal insulation backboard, and respectively arrange conductive copper strips on the upper edge and the lower edge of the coating substrate, and connect them to the positive and negative electrodes of the solar photovoltaic cell;

[0023] S04: Put graphene, carbon fiber, and carbon black into an oven to dry, then take them out and seal for standby. Take a set amount of water, heavy calcium, wetting dispersant, and ammonia and add them into a barrel. Then successively add conductive fillers such as graphene, carbon fiber, and carbon black, and stir at 1000 - 1500 r / min in a high-speed dispersing machine for 30 - 40 min, and then stir at 2500 - 3000 r / min for 1.5 - 2 h to make the conductive fillers disperse evenly. Add the binder water-based acrylic lactic acid glue and mix evenly at 2000 - 2500 r / min to obtain a composite carbon-based electrothermal material; where heavy calcium, as an auxiliary filler in the coating, can make the coating mildew-proof, not easy to settle, easy to disperse, and at the same time can increase the hardness of the coating and improve the weather resistance of the coating; the wetting dispersant can effectively reduce the intermolecular interaction force so that various materials are evenly dispersed in the system; the water-based acrylic lactic acid glue, as a binder, plays the role of bonding and thickening; a relatively continuous structure is formed among the conductive fillers, and they contact each other to form a good spatial conductive network path. By controlling the proportion of the conductive fillers in the present invention, the surface temperature change of the coating can be reduced, the temperature uniformity can be increased, and the thermal performance of the coating can be improved.

[0024] S05: Coat the composite carbon-based electrothermal material on the surface of the coating substrate and connect it to the conductive copper strip to form a composite carbon-based electrothermal coating; to avoid generating holes during the brushing process, the composite carbon-based electrothermal coating is brushed in two times, and the second brushing is carried out after the first coating is dried. The total thickness of the coating is 0.1 - 0.3 mm, and it has the characteristics of strong adhesion, fast heating, good heat resistance, and stable storage.

[0025] S06: The metal oxide precursors of Mn(NO3)2·6H2O, KMnO4 and (NH4)2Ce(NO3)6 were added to deionized water in a molar ratio of 3:2:5 by coprecipitation method, stirred evenly, potassium hydroxide solution was added dropwise and the pH value of the mixed solution was adjusted to 10.5, the temperature of the mixed solution was controlled at 45 - 50 °C, and strong stirring was carried out to obtain a brown precipitate; the obtained brown precipitate was aged in the mother liquor at 45 - 50 °C for 1 - 2 hours. Then it was filtered, the precipitate was washed, and the precipitate was placed in a drying oven to dry for 12 - 15 hours to remove moisture, and the drying temperature was above 110 °C. Finally, the dried precipitate was calcined in a tubular furnace at 500 °C for 5 - 7 hours to obtain a black thermal catalyst MnO x -CeO2 powder; the physical mixture of MnO x and CeO2 was prepared; the catalyst prepared by the improved coprecipitation method has high catalytic performance; it can improve the air purification ability.

[0026] S07: The ground MnO x -CeO2 powder was adhered to the surface of the composite carbon-based electrothermal coating to form a MnO x -CeO2 thermal catalytic coating, and after curing, a composite carbon-based electrothermal coating thermal catalytic indoor air purification wall surface was obtained.

[0027] Furthermore, in step S04, the composite carbon-based electrothermal material includes the following component materials: water: 50% - 60%, heavy calcium: 15% - 20%, wetting and dispersing agent: 5% - 7%, ammonia water: 0.4% - 1%, waterborne acrylic lactic acid glue: 5% - 10%, graphene: 1% - 3%, carbon fiber: 0.5% - 1%, carbon black: 1.5% - 3%. Carbon fiber can improve the heating rate of the surface of the composite carbon-based electrothermal coating. When the addition amount of carbon fiber is insufficient, the heating rate of the coating is insufficient and the heating efficiency is slow, but if the addition amount of carbon fiber is too large, the carbon fiber will be exposed on the surface of the coating, resulting in uneven coating thickness, and further making the surface temperature of the composite carbon-based electrothermal coating uneven, affecting the construction and use effect of the MnO x -CeO2 thermal catalytic coating. By limiting the carbon fiber to account for 0.5% - 1% of the total coating in the present invention, the surface temperature uniformity of the coating is ensured, and the adsorption effect of the MnO x -CeO2 thermal catalytic coating is improved.

[0028] Further, in step S06, the ratio of Mn(NO3)2·6H2O to deionized water is 0.04 mol / l; the molar concentration of the potassium hydroxide solution is 2 mol / l. The MnOx-CeO2 catalyst prepared by the present invention exhibits very high catalytic activity for the complete oxidation reaction of formaldehyde. The conversion rate of formaldehyde gradually increases with the increase in the temperature of the composite carbon-based electrothermal material, and HCHO can be completely oxidized to CO2 and H2O at 50°C.

[0029] The beneficial effects of the present invention are as follows:

[0030] (1) The present invention combines a composite carbon-based electrothermal coating and a MnO x -CeO2 thermal catalytic coating, utilizes the solar photovoltaic and building integration technology, drives the composite carbon-based electrothermal coating through solar energy to reduce building energy consumption for indoor heating, and then drives the MnO x -CeO2 thermal catalytic coating to purify indoor pollutants through the heat of the composite carbon-based electrothermal coating, realizing the functions of heating and air purification at the same time, and providing a method for removing pollutants when indoor ventilation cannot be carried out for a long time in winter. Compared with the prior art, the present invention satisfies the functions of traditional building walls while having the functions of heating and purification. And the composite carbon-based electrothermal coating and the MnO x -CeO2 thermal catalytic coating are coated on the interior wall of the building, basically not occupying indoor space; at the same time, the MnO x -CeO2 thermal catalytic coating continuously completes the cycle of purifying pollutants through the heat provided by the composite carbon-based electrothermal coating, can repeatedly remove pollutants, and has a long duration;

[0031] (2) The present invention senses the outdoor temperature through a temperature control valve and automatically adjusts the path between the solar photovoltaic cell, the conductive unit, and the external storage battery according to the temperature. Ensure the heat dissipation effect of the composite carbon-based electrothermal coating, and then improve the catalytic purification effect of the MnO x -CeO2 thermal catalytic coating. At the same time, in the non-heating season or high-temperature weather, the external storage battery is used to store the excess energy of the solar photovoltaic cell, improving the resource utilization effect;

[0032] (3) In the present invention, by compounding and mixing conductive fillers, graphene is evenly dispersed and attached to the surface of carbon fibers through the stirring of a high-speed dispersing machine, the contact between the two is closer, at the same time, the porosity of the coating is reduced and a more dense three-dimensional conductive network path is formed, slightly increasing the conductive network path of the coating; carbon black is attached to graphene or filled in the voids, and carbon fibers connect the two better. After the three come into contact, a relatively continuous structure is formed between the conductive fillers, forming a good spatial conductive network path, reducing the surface temperature change of the coating, increasing the temperature uniformity, and improving the thermal performance of the coating. Description of the Drawings

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0034] Figure 1 It is a schematic cross-sectional structure diagram at the self-wiring terminal of the air purification wall surface in the embodiment of the present invention;

[0035] Figure 2 It is a schematic structure diagram of a composite carbon-based electrothermal coating thermally catalytic indoor air purification wall surface in the embodiment of the present invention;

[0036] Figure 3 is Figure 2 a partial enlarged view of A in;

[0037] Figure 4 It is a schematic structure diagram of the indoor side of the composite carbon-based electrothermal coating thermally catalytic indoor air purification wall surface in the embodiment of the present invention.

[0038] Reference numerals: 10, solar photovoltaic cell; 20, building wall; 21, wire groove; 30, air purification unit; 31, thermal insulation and heat insulation backboard; 32, coating substrate; 33, conductive unit; 331, wiring terminal; 332, conductive copper strip; 333, insulating heat shrinkable sleeve; 34, composite carbon-based electrothermal coating; 35, MnOx-CeO2 thermally catalytic coating. Detailed implementation manners

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments.

[0040] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation manner.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of this invention are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0042] In a specific embodiment of the present invention, the sources of various commercially available materials are as follows:

[0043]

[0044] Example 1

[0045] As Figures 1-4 shown, a wall surface of a composite carbon-based electrothermal coating 34 for thermally catalytic indoor air purification, the wall surface from outside to inside is successively a solar photovoltaic cell 10, a building wall 20 and an air purification unit 30, and the solar photovoltaic cell 10 is connected to the air purification unit 30 through a wire; specifically, a wire groove 21 is formed on the building wall 20, and the wire passes through the wire groove 21 to connect the solar photovoltaic cell 10 and the air purification unit 30. The solar photovoltaic cell 10 uses a double-sided double-glass solar monocrystalline silicon photovoltaic cell and is fixed on the outer side of the building wall 20 by means of a support frame, expansion bolts, etc., and is connected to a conductive copper strip 332 through a wire.

[0046] The air purification unit 30 includes a heat-insulating and heat-preserving back plate 31, a coating substrate 32, a conductive unit 33, a composite carbon-based electrothermal coating 34 and a MnOx-CeO2 thermally catalytic coating 35. The heat-insulating and heat-preserving back plate 31 is arranged in contact with the building wall 20, the coating substrate 32 is arranged on the side of the heat-insulating and heat-preserving back plate 31 away from the building wall 20, and the composite carbon-based electrothermal coating 34 is arranged on the surface of the coating substrate 32; the conductive unit 33 is arranged at both ends of the coating substrate 32 and is connected to the solar photovoltaic cell 10 through a wire; the MnOx-CeO2 thermally catalytic coating 35 is arranged on the composite carbon-based electrothermal coating 34 to catalyze and purify indoor air.

[0047] The present invention combines a composite carbon - based electrothermal coating 34 and an MnOx - CeO2 thermal catalytic coating 35. Utilizing the solar photovoltaic - building integration technology, the composite carbon - based electrothermal coating 34 is driven by solar energy to provide heating for indoor use and reduce building energy consumption. Then, the heat of the composite carbon - based electrothermal coating 34 drives the MnOx - CeO2 thermal catalytic coating 35 to purify indoor pollutants, realizing the functions of heating and air purification simultaneously, and providing a method for removing pollutants when indoor ventilation cannot be carried out for a long time in winter. Compared with the prior art, the present invention satisfies the functions of the traditional building wall 20 while having the functions of heating and purification. Moreover, the composite carbon - based electrothermal coating 34 and the MnOx - CeO2 thermal catalytic coating 35 coated on the interior wall of the building basically do not occupy indoor space; at the same time, the MnOx - CeO2 thermal catalytic coating 35 continuously completes the cycle of purifying pollutants through the heat provided by the composite carbon - based electrothermal coating 34, can repeatedly remove pollutants, and has a long duration.

[0048] As Figure 4 shown, the conductive unit 33 includes a terminal 331 and a conductive copper strip 332. The conductive copper strip 332 is arranged at both ends of the coating substrate 32 and is connected to the composite carbon - based electrothermal coating 34; the terminal 331 is arranged on the conductive copper strip 332 and is connected to the solar photovoltaic cell 10 through a wire. In this embodiment, the positive electrode of the solar photovoltaic cell 10 is connected to the terminal 331 on the conductive copper strip 332 at the upper edge of the room, and the negative electrode of the solar photovoltaic cell 10 is connected to the terminal 331 on the conductive copper strip 332 at the lower edge of the room; those skilled in the art can adjust according to the actual situation.

[0049] To improve the wall safety, the conductive unit 33 further includes an insulating heat - shrinkable sleeve 333. The insulating heat - shrinkable sleeve 333 is arranged on the outer surfaces of the conductive copper strip 332 and the terminal 331. By heating, the outer skin shrinks back and tightly compresses on the surface of the conductive copper strip 332 to avoid electric leakage.

[0050] Specifically, the solar photovoltaic cell 10 is fixed on the outer side of the building wall 20 through a support frame.

[0051] To achieve intelligent regulation, a temperature control valve is arranged between the solar photovoltaic cell 10 and the air purification unit 30. The output end of the temperature control valve is connected to the conductive unit 33 and an external storage battery. The temperature control valve senses the temperature and automatically adjusts the path between the solar photovoltaic cell 10, the conductive unit 33, and the external storage battery.

[0052] Preferably, the temperature control valve is provided with a first threshold and a second threshold, and the second threshold is greater than the first threshold; when the temperature is lower than the first threshold, the output end of the solar photovoltaic cell 10 and the output end of the external storage battery are respectively connected to the conductive unit 33; under the action of solar radiation, while the conductive unit 33 generates electricity, the temperature of the composite carbon-based electrothermal coating 34 rises, and the thermal catalytic layer is heated. At the same time, the external storage battery provides power for the conductive unit 33 to ensure the thermal catalytic effect. When the temperature is between the first threshold and the second threshold, the external storage battery is disconnected from the conductive unit 33; when the temperature is higher than the second threshold, the output end of the solar photovoltaic cell 10 is connected to the external storage battery, and the generated electric energy is sent to other areas in the building for use.

[0053] It should be noted here that in this embodiment, the first threshold is 5 °C and the second threshold is 10 °C. When the temperature is lower than 5 °C, the solar photovoltaic cell 10 and the external storage battery supply power to the conductive unit 33 at the same time; to avoid the influence of insufficient energy storage of the solar photovoltaic cell 10 on the composite carbon-based electrothermal coating 34 due to too low temperature. When the temperature is ≥5 °C and ≤10 °C, the external storage battery is disconnected from the conductive unit 33, and only the solar photovoltaic cell 10 supplies power to the conductive unit 33. When the temperature is higher than 10 °C, the solar photovoltaic cell 10 is disconnected from the conductive unit 33, and the generated electric energy is input into the external storage battery for storage. It can be found that when the outdoor temperature is lower than 10 °C, the solar photovoltaic cell 10 is connected to the conductive unit 33. After being irradiated by sunlight to generate electric energy, it is transmitted to the conductive copper strip 332 through a wire and a voltage regulator. The conductive copper strip 332 transfers the electric energy to the composite carbon-based electrothermal coating 34. The composite carbon-based electrothermal coating 34 stably receives the electric energy to generate heat and transports it to the indoor. The heat transmitted to the outside of the building wall 20 is intercepted by the heat-insulating and heat-reflecting back plate 31 and stored indoors to avoid heat dissipation. The composite carbon-based electrothermal coating 34 continues to heat up, activating the MnOx-CeO2 thermal catalytic coating 35 on the surface. The pollutants in the indoor air diffuse to the surface of the MnOx-CeO2 thermal catalytic coating 35 through convective mass transfer. After being adsorbed by the MnOx-CeO2 thermal catalytic coating 35, a thermal catalytic reduction reaction is carried out. Then the products generated by the reaction are desorbed from the coating surface and enter the indoor air again through convective diffusion mass transfer. And the products after the reaction are H2O and CO2, which are harmless to the human body and provide heat energy to the indoor at the same time. The setting of the temperature control valve in the present invention uses the electrical connection in different states of the first threshold and the second threshold to avoid the influence of the outdoor temperature on the coating temperature, ensure that the voltage of the composite carbon-based electrothermal coating 34 is about 18 to 24 v, and ensure the catalytic effect of the MnOx-CeO2 thermal catalytic coating 35.

[0054] Such as Figure 3As shown, the coating thickness of the composite carbon-based electrothermal coating 34 is 0.2 mm, and the coating thickness of the MnOx-CeO2 thermal catalytic coating 35 is 0.2 mm. At this time, the total thickness of the composite carbon-based electrothermal coating 34 and the MnOx-CeO2 thermal catalytic coating 35 is 0.4 mm.

[0055] Preferably, a voltage stabilizer is further provided between the solar photovoltaic cell 10 and the conductive unit 33, which serves to stabilize the output voltage of the solar photovoltaic cell 10 and the temperature of the composite carbon-based electrothermal coating 34.

[0056] Specifically, in this embodiment, the construction method of the composite carbon-based electrothermal coating for purifying indoor air on the wall includes the following operation steps:

[0057] S01: Fix the solar photovoltaic cell on the outer side of the building wall using a support frame;

[0058] S02: The thermal insulation and heat insulation backboard is a polyethylene board, and the polyethylene board is arranged on the inner surface of the building wall; the thickness of the polyethylene board is about 3 mm, and it is fixed along the edge of the polyethylene board through high-concentration PVC glue and expansion screws.

[0059] S03: The coating substrate is a gypsum board, and the gypsum board is fixedly connected to the polyethylene board. The thickness of the gypsum board is about 2 mm and serves as the backboard for coating the composite carbon-based electrothermal coating. Among them, conductive copper strips are respectively arranged on the upper edge and the lower edge of the gypsum board and are connected to the positive and negative electrodes of the solar photovoltaic cell; the width of the conductive copper strip is 50 mm and the thickness is 0.3 mm.

[0060] S04: Take a certain amount of water, heavy calcium, wetting and dispersing agent, ammonia water-based acrylic lactic acid glue and add them to the barrel, and then sequentially add conductive fillers such as graphene, carbon fiber, and carbon black and stir and disperse them. Stir at 1000 r / min in a high-speed disperser for 30 min, and then stir at 3000 r / min for 1.5 h to make the conductive fillers disperse evenly. Add a binder and mix evenly at 2000 r / min to obtain a composite carbon-based electrothermal material;

[0061] Among them, the mass ratios of water, heavy calcium, wetting and dispersing agent, ammonia water-based acrylic lactic acid glue and conductive fillers are 50% water, 15% heavy calcium, 5% wetting and dispersing agent, 0.4% ammonia water, 5% water-based acrylic lactic acid glue, 1.5% graphene, 0.5% carbon fiber, and 1.5% carbon black. In the composite carbon-based electrothermal coating, graphene accounts for about 3% of the total coating, carbon fiber accounts for about 1% of the total coating, and carbon black accounts for about 3% of the total coating.

[0062] S05: Coat the composite carbon-based electrothermal material on the surface of the gypsum board and connect it to the conductive copper strip to form a composite carbon-based electrothermal coating. To avoid generating holes during the painting process, the composite carbon-based electrothermal coating is painted in two coats. The second coat is applied after the first coat is dried. The total thickness of the coating is 0.2 mm, and it features strong adhesion, fast heating, good heat resistance, and stable storage.

[0063] S06: Add 6 mmol of manganese nitrate hexahydrate (Mn(NO3)2·6H2O), 4 mmol of potassium permanganate (KMnO4), and 10 mmol of ammonium cerium nitrate ((NH4)2Ce(NO3)6) to 150 ml of deionized water, stir until a homogeneous mixed solution is obtained, and seal for later use. Gradually add 2 mol / l potassium hydroxide (KOH) solution and adjust the pH value of the mixed solution to 10.5. Control the temperature of the mixed solution at 50 °C and stir vigorously. The obtained brown precipitate is aged in the mother liquor at 50 °C for another 2 hours. Then filter and wash the precipitate. Place the precipitate in a drying oven and dry it for 12 hours to remove moisture. The drying temperature is 110 °C. Finally, place the dried precipitate in a tubular furnace and calcine it at 500 °C for 6 hours to obtain the black thermal catalyst MnO x -CeO2.

[0064] S07: Add the ground MnO x -CeO2 powder and sodium silicate nonahydrate to a certain amount of deionized water in a ratio of 50:1 and stir. Then add a certain amount of binder and mix evenly under stirring. Bond it to the surface of the composite carbon-based electrothermal coating in two steps to form a MnO x -CeO2 thermal catalytic coating. After curing, a wall surface for purifying indoor air with a thermal catalyst on the composite carbon-based electrothermal coating is obtained.

[0065] Specifically, the total thickness of the MnO x -CeO2 thermal catalytic coating is 0.4 mm. When painting on the inner surface of the building wall, to avoid missed painting, air bubbles, and small holes, it is painted in two coats. After the first coat is completed and the catalyst coating is completely dried, the second coat is applied to reduce the probability of holes, air bubbles, or missed painting.

[0066] Example 2

[0067] In this example, under the same construction method as in Example 1, in step S04, the mass percentages of each component are 60% water, 15% heavy calcium, 5% wetting and dispersing agent, 0.4% ammonia water, 10% waterborne acrylic lactic acid glue, 3% graphene, 1% carbon fiber, and 3% carbon black. In the composite carbon-based electrothermal coating, graphene accounts for about 3% of the total coating, carbon fiber accounts for about 1% of the total coating, and carbon black accounts for about 3% of the total coating.

[0068] The remaining steps and settings are similar to those in Example 1 and will not be elaborated here.

[0069] Example 3

[0070] In this example, when the construction method is the same as that in Example 1, in step S04, the mass percentages of each component are 55% water, 17% heavy calcium carbonate, 7% wetting and dispersing agent, 1% ammonia water, 5% waterborne acrylic lactic acid glue, 2% graphene, 0.7% carbon fiber, and 2% carbon black.

[0071] The remaining steps and settings are the same as those in Example 1 and will not be elaborated here.

[0072] Comparative Example 1

[0073] In this example, there is no MnO x -CeO2 coating. When the construction method is the same as that in Example 1, there is no MnO x -CeO2 coating until the preparation in step S04 is completed.

[0074] The remaining steps and settings are the same as those in Example 1 and will not be elaborated here.

[0075] Comparative Example 2

[0076] In this example, when the construction method is the same as that in Example 1, in step S04, the mass percentages of each component are 50% water, 15% heavy calcium carbonate, 5% wetting and dispersing agent, 0.4% ammonia water, 5% waterborne acrylic lactic acid glue, and 3% carbon fiber.

[0077] The remaining steps and settings are the same as those in Example 1 and will not be elaborated here.

[0078] Comparative Example 3

[0079] In this example, when the construction method is the same as that in Example 1, in step S04, the mass percentages of each component are 50% water, 15% heavy calcium carbonate, 5% wetting and dispersing agent, 0.4% ammonia water, 5% waterborne acrylic lactic acid glue, and 1.5% graphene.

[0080] The remaining steps and settings are the same as those in Example 1 and will not be elaborated here.

[0081] Performance Verification

[0082] The following Table 1 shows the performance test results of Examples 1 to 3 and Comparative Examples 1 to 3 in the present invention

[0083] Table 1 Comparison of Performance Test Results

[0084]

[0085] Comparative Example 1, compared with Example 1, has no MnOx-CeO2 coating, and it can only achieve the purpose of raising the indoor temperature by thermal radiation, and cannot purify aldehyde gases such as formaldehyde in the room.

[0086] Comparative Example 2, compared with Example 1, only has carbon fiber in the carbon-based material, without graphene and carbon black materials. Then, a space conductive network path cannot be formed on the surface of the coating, resulting in a slow heating rate of the coating. At the same time, due to the excessive addition amount of carbon fiber, the carbon fiber is exposed on the surface of the coating, resulting in uneven coating thickness. Furthermore, the surface temperature distribution of the composite carbon-based electrothermal coating is uneven, and there is a phenomenon of overheating at a certain part of the coating, and it cannot dissipate heat evenly to the room. At the same time, since MnOx-CeO2 requires a certain temperature as an activation condition, without the promotion of an appropriate temperature, the indoor temperature cannot reach the target temperature for activating the MnOx-CeO2 purification coating, nor can it achieve the effect of purifying indoor air.

[0087] Comparative Example 3, compared with Example 1, only has graphene in the carbon-based material, without carbon fiber and carbon black materials. This causes a significant deficiency in the heating rate of the coating, and the heating efficiency is very slow. At the same time, due to the lack of addition of carbon black, the volume resistivity of the coating increases, the heat generation is not high, and the surface temperature of the coating is low. Since the surface temperature of the coating is closely related to the catalytic efficiency of the MnOx-CeO2 thermal catalytic coating, it has a negative impact on the use effect of the MnOx-CeO2 thermal catalytic coating.

[0088] Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite carbon-based electrothermal coating thermal catalytic indoor air purification wall surface, characterized in that, The wall surface from outside to inside is successively a solar photovoltaic cell, a building wall, and an air purification unit. The solar photovoltaic cell is connected to the air purification unit through a wire; The air purification unit includes a heat-insulating and heat-preserving backboard, a coated substrate, a conductive unit, a composite carbon-based electrothermal coating, and a MnO x -CeO2 thermal catalytic coating. The heat-insulating and heat-preserving backboard is attached to the building wall, the coated substrate is arranged on the side of the heat-insulating and heat-preserving backboard away from the building wall, and the composite carbon-based electrothermal coating is arranged on the surface of the coated substrate; the conductive unit is arranged at both ends of the coated substrate and is connected to the solar photovoltaic cell through a wire; the MnO x -CeO2 thermal catalytic coating is arranged on the composite carbon-based electrothermal coating to catalyze and purify the indoor air.

2. The composite carbon-based electrothermal coating thermal catalytic indoor air purification wall surface according to claim 1, wherein, The conductive unit includes a terminal and a conductive copper strip. The conductive copper strip is arranged at both ends of the coating substrate and is connected to the composite carbon-based electrothermal coating; the terminal is arranged on the conductive copper strip and is connected to the solar photovoltaic cell through a wire.

3. The composite carbon-based electrothermal coating thermal catalytic indoor air purification wall surface according to claim 2, characterized in that The conductive unit further includes an insulating heat shrink sleeve, and the insulating heat shrink sleeve is arranged on the outer surfaces of the conductive copper strip and the terminal.

4. A composite carbon-based electrothermal coating thermally catalytic indoor air purification wall surface according to claim 1, characterized in that, The solar photovoltaic cell is fixed on the outer side of the building wall through a support frame.

5. A composite carbon-based electrothermal coating heat-catalytic indoor air purification wall surface according to claim 1, characterized in that, A temperature control valve is arranged between the solar photovoltaic cell and the air purification unit. The output end of the temperature control valve is connected to the conductive unit and an external storage battery. The temperature control valve senses the temperature and automatically adjusts the path between the solar photovoltaic cell, the conductive unit, and the external storage battery.

6. The composite carbon-based electrothermal coating thermally catalytic indoor air purification wall surface according to claim 5, characterized in that, The temperature control valve is provided with a first threshold and a second threshold, and the second threshold is greater than the first threshold; When the temperature is lower than the first threshold, the output ends of the solar photovoltaic cell and the external storage battery are respectively connected to the conductive unit; When the temperature is between the first threshold and the second threshold, the external storage battery is disconnected from the conductive unit; When the temperature is higher than the second threshold, the output end of the solar photovoltaic cell is connected to the external storage battery.

7. A composite carbon-based electrothermal coating heat catalytic indoor air purification wall surface according to claim 1, characterized in that The coating thickness of the composite carbon-based electrothermal coating is 0.1 mm to 0.3 mm, and the coating thickness of the MnO x -CeO2 thermal catalytic coating is 0.1 mm to 0.3 mm.

8. A composite carbon-based electrothermal coating heat catalytic indoor air purification wall surface according to claim 7, characterized in that, The total thickness of the composite carbon-based electrothermal coating and the MnO x -CeO2 thermal catalytic coating is 0.4 to 0.5 mm.

9. A composite carbon-based electrothermal coating heat catalytic indoor air purification wall surface according to claim 1, characterized in that, A voltage stabilizer is further arranged between the solar photovoltaic cell and the conductive unit.

10. The construction method of a composite carbon-based electrothermal coating thermally catalytic indoor air purification wall according to any one of claims 1 to 9, characterized in that, It includes the following operation steps: S01: Fix the solar photovoltaic cell on the outer side of the building wall by using a support frame; S02: Arrange the heat-insulating and heat-preserving backboard on the inner surface of the building wall; S03: Fix and connect the coating substrate to the heat-insulating and heat-preserving backboard, arrange conductive copper strips at the upper edge and the lower edge of the coating substrate respectively, and connect them to the positive and negative electrodes of the solar photovoltaic cell; S04: Coat the surface of the coating substrate with the composite carbon-based electrothermal material and connect it to the conductive copper strip to form a composite carbon-based electrothermal coating; S05: Bond the MnO x -CeO2 powder onto the surface of the composite carbon-based electrothermal coating to form a MnO x -CeO2 thermal catalytic coating. After curing, a wall for purifying indoor air in a thermal catalytic chamber of the composite carbon-based electrothermal coating is obtained.

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