Self-cleaning rare earth antibacterial ceramic material and preparation method thereof

Abstract

The application provides a self-cleaning rare earth antibacterial ceramic material and a preparation process thereof, which comprises a ceramic base and a functional glaze layer on the surface of the ceramic base. The functional glaze layer comprises an antibacterial holding phase and a self-cleaning photocatalytic phase. The antibacterial holding phase comprises rare earth oxide particles, a metal ion source and a borosilicate holding network formed by firing a SiO2 source and a B2O3 source, the rare earth oxide is at least two of CeO2, La2O3 and Y2O3, and the metal ion source is at least one of silver, copper and zinc; the self-cleaning photocatalytic phase comprises CeO 2‑x / TiO2 composite particles and is enriched on the surface area of the glaze layer, and the thickness is 50-1000 nm. The self-cleaning rare earth antibacterial ceramic material and the preparation method thereof hold the antibacterial ion source through the rare earth oxide and construct the self-cleaning photocatalytic phase enriched on the surface of the glaze layer, so that the antibacterial and self-cleaning functions are stably exerted in cooperation under high-temperature firing conditions, the long-term antibacterial, anti-fouling and self-cleaning performance of the material is significantly improved, and the durability and practicability are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, and in particular to a self-cleaning rare earth antibacterial ceramic material and its preparation method. Background Technology

[0002] Ceramic materials, as inorganic non-metallic materials widely used in construction, home furnishings, sanitary ware, and industrial components, possess excellent heat resistance, chemical corrosion resistance, and mechanical strength. In recent years, with the development trend of functional materials, the demand for surface functionalities such as antibacterial properties and ease of cleaning has been continuously increasing. Especially in public health environments, medical facilities, and kitchen and bathroom settings, traditional ceramic materials are prone to the adhesion of stains and microorganisms. Conventional cleaning methods can only suppress contamination in the short term and cannot sustainably maintain antibacterial and self-cleaning functions, which brings considerable inconvenience and potential hygiene risks to use and maintenance.

[0003] To meet market demands for antibacterial, easy-to-clean, and self-cleaning functionalities in ceramic products, various solutions have been proposed in existing technologies. For example, invention CN105669035A discloses a self-cleaning and antibacterial ceramic glaze and its preparation method. This method achieves self-cleaning and antibacterial functions by adding materials in specific proportions to the ceramic glaze, mainly relying on adjustments to the glaze formulation and traditional high-temperature firing steps. While this technical solution can improve the anti-fouling and antibacterial properties of ceramic surfaces to some extent, its mechanism for achieving self-cleaning is relatively limited, and it does not fully address issues such as poor stability of the photocatalytic phase and difficulty in maintaining antibacterial activity over a long period under high-temperature firing conditions.

[0004] Another typical prior art document is CN105565667A, which discloses an easy-to-clean antibacterial sanitary ceramic and its preparation method. This method attempts to improve the easy-to-clean and antibacterial properties of sanitary ceramics by introducing composite components such as inorganic antibacterial materials, far-infrared materials, and mineral nanofibers into the glaze system. However, this method mainly achieves the functional combination through conventional formulation compounding. In the actual preparation process, there are no systematic limitations on the synergistic effect between functional components, long-term stability, and phase transition behavior under high temperature conditions. Therefore, it still suffers from defects such as the antibacterial effect weakening over time and insufficient self-cleaning efficiency.

[0005] Currently, most technologies proposed in the industry for the antibacterial and self-cleaning functions of ceramic materials rely on the traditional addition of photocatalysts (such as TiO2) or simply the addition of antibacterial components. However, under high-temperature firing conditions, common photocatalysts are prone to phase transitions, leading to a decrease in catalytic activity. Furthermore, the antibacterial active ingredients are unevenly dispersed in the glaze layer and struggle to form a long-term effective release and action mechanism, making it difficult for the functional performance of the products to meet the long-term effectiveness requirements of actual use environments. The aforementioned existing solutions fail to effectively address core technical issues such as the stability of functional phases caused by high-temperature firing, the synergy of antibacterial and self-cleaning functions, and the maintenance of anti-fouling effects during long-term use. These pain points are prevalent in the ceramic functional materials industry and have not yet been effectively resolved.

[0006] Therefore, how to provide a ceramic material with long-lasting antibacterial and self-cleaning functions to solve the technical problems in the prior art, such as the difficulty in maintaining the stability of functional components under high-temperature firing conditions and the difficulty in maintaining antibacterial and self-cleaning effects for a long time, and to achieve stable and long-term antibacterial and self-cleaning properties of ceramic materials in complex usage environments, is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] To address the shortcomings of existing technologies, such as difficulty in maintaining antibacterial activity over a long period, insufficient self-cleaning function, weak bonding between the functional layer and the substrate, and easy deactivation of the photocatalytic phase after high-temperature firing, this invention provides a self-cleaning rare-earth antibacterial ceramic material and its preparation method, which uses rare-earth oxides to immobilize the antibacterial ion source and constructs a self-cleaning photocatalytic phase enriched on the glaze surface. This allows the antibacterial and self-cleaning functions to work synergistically and stably under high-temperature firing conditions, significantly improving the long-term antibacterial, antifouling, and self-cleaning properties of the material, and achieving a significant improvement in durability and practicality.

[0008] In a first aspect, the present invention provides a self-cleaning rare earth antibacterial ceramic material, characterized in that it comprises a ceramic matrix and a functional glaze layer formed on the surface of the ceramic matrix; the functional glaze layer comprises an antibacterial retaining phase and a self-cleaning photocatalytic phase; The antibacterial holding phase comprises rare earth oxide particles, a metal ion source, and a borosilicate holding network. The rare earth oxide is selected from at least two of CeO2, La2O3, and Y2O3. The metal ion source is selected from at least one of silver, copper, and zinc. The borosilicate holding network is formed by sintering a SiO2 source and a B2O3 source. The self-cleaning photocatalytic phase includes CeO. 2-x / TiO2 composite particles, wherein CeO 2-x / TiO2 composite particles are enriched in the surface region of the functional glaze layer, and the surface region has a thickness of 50-1000 nm.

[0009] This invention constructs a functional glaze layer containing an antibacterial holding phase and a self-cleaning photocatalytic phase on the surface of a ceramic matrix. This allows the antibacterial metal ion source to be stably held at high temperatures by a rare earth oxide and borosilicate holding network. This significantly improves the thermal stability and long-term release performance of the antibacterial components under high-temperature firing conditions, effectively inhibits the adhesion and reproduction of microorganisms, and improves the problem of the decay of the antibacterial effect of conventional ceramic materials over time.

[0010] Meanwhile, this invention enriches CeO2-x / TiO2 composite photocatalytic particles on the surface region of the functional glaze layer. This composite phase improves the separation efficiency of photogenerated carriers and enhances the visible light response through interfacial synergy, enabling the ceramic surface to efficiently decompose organic stains and pollutants under light conditions, thereby obtaining durable self-cleaning performance and improving the overall stain resistance and maintainability of the material.

[0011] Preferably, based on the total dry-based solid phase of the functional glaze layer: the content of the antibacterial retaining phase is 0.5-6 wt%, and the content of CeO is... 2-x The content of the TiO2 composite particles is 0.1-3wt%.

[0012] Within this preferred range, the content of the antibacterial retaining phase can provide sufficient antibacterial ion slow-release capacity while avoiding excessive volatilization or mutual interference of components during high-temperature firing; the content of CeO2-x / TiO2 composite particles is sufficient to form a continuous self-cleaning functional area on the glaze surface, while avoiding excessive content that could lead to abnormal glaze color or increased risk of material cracking, thereby comprehensively improving the long-term practicality and stability of self-cleaning rare earth antibacterial ceramic materials.

[0013] Preferably, the molar ratio of SiO2 to B2O3 in the borosilicate retaining network is (1~6):1, and the metal ion source is dispersed in at least one of metal oxide, metal silicate, metal borate, and metal phosphate and retained by the borosilicate retaining network.

[0014] This molar ratio range is beneficial for forming a borosilicate retention network with a good glassy phase framework structure during high-temperature firing, thereby effectively retaining the antibacterial metal ion source and inhibiting its aggregation or volatilization, enhancing the thermal stability and dispersion uniformity of the antibacterial retention phase, and allowing the antibacterial metal ion source to exist in the retention network in the form of chemical bonding or structural retention, improving the dispersion stability during glaze application and high-temperature firing, and helping to form a long-term effective antibacterial functional region in the ceramic glaze layer.

[0015] Preferably, the CeO 2-x The TiO2 composite particles have a core-shell or interpenetrating structure, and the TiO2 is anatase phase; the CeO2... 2-x The D50 of the / TiO2 composite particles is 5-80nm.

[0016] This optimized structure enables the TiO2 anatase phase to form a stable photocatalytic framework, while CeO2-x, as the core or interpenetrating phase, maintains close contact with TiO2 at the nanoscale. This facilitates the formation of efficient interfacial heterojunctions, promoting the separation and migration of photogenerated electron-hole pairs and improving photocatalytic self-cleaning efficiency. The nanoscale D50 range (5-80 nm) not only increases the specific surface area of ​​the composite particles, effectively improving surface photocatalytic activity, but also forms a dense and uniform enrichment region on the glaze surface. This avoids increased glaze roughness due to excessively large particles or agglomeration due to excessively fine particles, thus achieving a more stable and durable self-cleaning function.

[0017] Preferably, the functional glaze layer has a component gradient distribution along the thickness direction: the enrichment region of the antibacterial retaining phase is located within the thickness range close to the ceramic matrix, and the CeO... 2-x The enrichment zone of the / TiO2 composite particles is located in the thickness range away from the ceramic matrix.

[0018] Through the aforementioned gradient distribution structure design, the antibacterial retained phase is preferentially distributed in the inner layer close to the matrix, which is beneficial for forming a stable antibacterial sustained-release region during high-temperature sintering, thereby improving the thermal stability and long-term release effect of the antibacterial components; at the same time, CeO 2-x The TiO2 composite particles are concentrated in the surface region away from the matrix, maximizing the exposure of the self-cleaning photocatalytic phase to external pollutants and light conditions, effectively enhancing the self-cleaning function. This component gradient distribution along the thickness direction not only achieves spatial separation and chemical complementarity between antibacterial and self-cleaning functions, but also improves the stress distribution within the glaze layer and the bonding stability with the ceramic matrix, thereby comprehensively enhancing the material's functionality and durability.

[0019] Preferably, the thickness of the functional glaze layer is 10-200 μm, and the surface of the functional glaze layer has a micro-nano composite morphology, wherein the micro-nano composite morphology is composed of nano-sized CeO 2-x / TiO2 composite particles together form a micron-sized glaze phase solidification framework.

[0020] This limited thickness range not only facilitates the formation of a sufficiently thick functional layer on the ceramic substrate surface to support antibacterial and self-cleaning components, but also provides balanced mechanical strength and functional performance during actual use; the micro-nano composite morphology is achieved through nanoscale CeO 2-x The synergistic construction of TiO2 composite particles and micron-sized glaze phase solidification skeleton not only increases the effective exposure area of ​​functional phases and improves photocatalytic and antibacterial activities, but also improves the continuity and density of the microstructure of the glaze surface, thereby enhancing the stability of self-cleaning effect and anti-pollution performance. At the same time, it avoids the increase in glaze surface roughness caused by particle agglomeration or wrinkles, significantly enhancing the overall performance and appearance quality of the material.

[0021] Secondly, the present invention also provides a preparation process for the self-cleaning rare earth antibacterial ceramic material, comprising the following steps:

[0022] S1. Preparation of antibacterial retaining powder: Rare earth oxides or their precursors, SiO2 source, B2O3 source and metal ion source are added to an aqueous medium and wet-mixed and dispersed to obtain a mixed slurry; the mixed slurry is dried and granulated, and then heat-treated at 450-900℃ for 1-4 hours to obtain antibacterial retaining powder containing a rare earth oxide and borosilicate retaining network;

[0023] S2. Preparation of glaze slurry: After mixing the basic glaze raw materials with the antibacterial retaining powder, the mixture is ball-milled to obtain a glaze slurry for glazing. S3. Glazing and drying: Apply the glaze slurry to the surface of the ceramic body or bisque-fired body and dry it; S4. Glazing: The dried body is fired at 1180-1250℃ for 30-120 minutes, and after cooling, a functional glaze layer containing an antibacterial retention phase is obtained. S5. Constructing a self-cleaning photocatalytic phase: Coating the surface of the functional glaze layer with a CeO2-containing phase. 2-x The dispersion of / TiO2 composite particles was solidified, allowing CeO2 to form a solidified solution. 2-x / TiO2 composite particles form an enriched structure on the surface region of the functional glaze layer.

[0024] Preferably, the aqueous medium in step S1 contains a dispersant, which includes polyethylene glycol; the ball milling time in step S2 is 4-18 hours.

[0025] Preferably, the dispersion in step S5 further includes silica sol, which is a cationic silica sol; the curing temperature in step S5 is 150-450℃, and the curing time is 0.5-2h.

[0026] Preferably, the CeO 2-x / TiO2 composite particles were obtained by reduction treatment to obtain CeO 2-x The structure, wherein the reduction treatment is performed at 300-600℃ for 0.5-2h under a hydrogen-containing protective atmosphere, and x is 0.01-0.20.

[0027] The present invention provides a self-cleaning rare earth antibacterial ceramic material and its preparation method, which has at least the following beneficial effects: The self-cleaning rare-earth antibacterial ceramic material and its preparation method provided by this invention have at least the following beneficial effects: (1) This invention constructs a functional glaze layer containing an antibacterial holding phase and a self-cleaning photocatalytic phase on the surface of a ceramic matrix. This allows the antibacterial metal ion source to be stably held at high temperatures under the synergistic effect of the borosilicate holding network and rare earth oxide particles, reducing the risk of migration, aggregation, and deactivation during the firing process, thereby achieving a more durable antibacterial effect; at the same time, CeO 2-x / TiO2 composite particles are enriched on the surface of the glaze layer. By utilizing the reversible valence state and oxygen vacancy characteristics of CeO2, the separation of photogenerated carriers and the generation of reactive species are promoted at the interface, thereby improving the photocatalytic decomposition of organic stains and obtaining more stable self-cleaning performance. In addition, the adverse effects of dirt film covering on antibacterial activity are reduced during use, and the synergistic performance of antibacterial and self-cleaning is enhanced.

[0028] (2) This invention utilizes an antibacterial holding phase and CeO2 2-x The content window of the TiO2 composite particles, the molar ratio window of SiO2 to B2O3 in the borosilicate retaining network, and the nanoscale structural morphology of the composite particles are defined to suppress particle agglomeration and glaze defects while satisfying the effective content of the functional phase. This maintains the basic properties of the glaze, such as density and wear resistance, and allows the photocatalytic phase and antibacterial phase to form a more reasonable spatial division of labor in the thickness direction of the glaze. Furthermore, by combining the component gradient distribution in the thickness direction and the micro-nano composite morphology, it is beneficial to concentrate the self-cleaning photocatalytic ability on the surface and enhance the effective exposure area, while forming a more stable antibacterial slow-release region inside, thereby comprehensively improving the anti-fouling and easy-to-clean properties as well as the antibacterial durability.

[0029] (3) The preparation method of the present invention, through the pre-construction of antibacterial holding powder, ball milling and dispersion of glaze slurry, conventional glazing and high-temperature glazing, and construction and solidification of surface self-cleaning phase, makes the introduction path and distribution position of functional components controllable, which is convenient to be compatible with existing ceramic glazing and firing processes, and is conducive to improving the density of glaze surface and stability of functional phase after high-temperature firing, thereby achieving more reliable large-scale preparation and long-term service performance. Detailed Implementation

[0030] To better understand the above technical solutions, a detailed description of the specific implementation methods will be provided below. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0032] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0033] This invention provides a self-cleaning rare-earth antibacterial ceramic material, comprising a ceramic matrix and a functional glaze layer formed on the surface of the ceramic matrix. The ceramic matrix is ​​a ceramic body or a bisque-fired body, and can be selected from conventional matrix systems such as sanitary ceramics, building ceramics, or daily-use ceramics, depending on the application scenario. The functional glaze layer is formed by applying a glaze slurry to the surface of the ceramic matrix and then firing it. The glaze slurry consists of dry-based glaze solid raw materials and a liquid-phase dispersion medium. After firing, the dry-based glaze solid raw materials form a glaze matrix and carry the functional phase components. The liquid-phase dispersion medium disperses the dry-based glaze solid raw materials into a slurry system suitable for glazing.

[0034] The functional glaze layer specifically includes:

[0035] (1) Antibacterial retaining phase, wherein the antibacterial retaining phase is dispersed in the glaze matrix of the functional glaze layer and is fired synchronously with the glaze layer; the antibacterial retaining phase includes rare earth oxide particles, metal ion source and borosilicate retaining network, wherein the rare earth oxide particles are selected from at least two of CeO2, La2O3 and Y2O3, the metal ion source is selected from at least one of silver, copper and zinc, and the borosilicate retaining network is formed by firing SiO2 source and B2O3 source.

[0036] In one preferred embodiment, the content of the antibacterial retaining phase is 0.5-6 wt%, based on the total dry solid phase of the functional glaze layer.

[0037] In one preferred embodiment, the molar ratio of SiO2 to B2O3 in the borosilicate holding network is (1-6):1, and the metal ion source is dispersed in at least one of metal oxides, metal silicates, metal borates, and metal phosphates and held by the borosilicate holding network.

[0038] In a more preferred embodiment, the SiO2 source is selected from at least one of silica powder and silica sol, the B2O3 source is selected from at least one of B2O3 powder, boric acid or borate, the rare earth oxide particles are the corresponding oxide powder or precursor powder that can be converted into the corresponding oxide during heat treatment, and the metal ion source is at least one of oxides, silicates, borates or phosphates of silver, copper, and zinc.

[0039] (2) A self-cleaning photocatalytic phase, wherein the self-cleaning photocatalytic phase comprises CeO 2-x / TiO2 composite particles, wherein CeO 2-x / TiO2 composite particles are enriched in the surface region of the functional glaze layer, and the surface region has a thickness of 50-1000 nm.

[0040] In one preferred embodiment, the content of the CeO2-x / TiO2 composite particles is 0.1-3 wt%, based on the total dry solid phase of the functional glaze layer.

[0041] In one preferred embodiment, the CeO 2-x The / TiO2 composite particles have a core-shell structure or an interpenetrating structure, and the TiO2 is anatase phase; the D50 of the CeO2-x / TiO2 composite particles is 5-80 nm.

[0042] In one preferred embodiment, the functional glaze layer has a component gradient distribution along the thickness direction: the enrichment region of the antibacterial retaining phase is located within the thickness range close to the ceramic matrix, and the CeO... 2-x The enrichment zone of the / TiO2 composite particles is located in the thickness range away from the ceramic matrix.

[0043] In a more preferred embodiment, the thickness of the functional glaze layer is 10-200 μm, and the surface of the functional glaze layer has a micro-nano composite morphology, which is composed of nano-sized CeO. 2-x / TiO2 composite particles together form a micron-sized glaze phase solidification framework.

[0044] The preparation method of the above-mentioned self-cleaning rare earth antibacterial ceramic material specifically includes the following steps: S1. Preparation of antibacterial retaining powder: Rare earth oxides or their precursors, SiO2 source, B2O3 source, and metal ion source are added to an aqueous medium and wet-mixed and dispersed to obtain a mixed slurry; wherein, the SiO2 source can be silica powder or silica sol, the B2O3 source can be B2O3 powder or a boron source that can be converted to B2O3 during heat treatment, and the metal ion source can be oxides, silicates, borates, or phosphates of silver, copper, or zinc; in one preferred embodiment, the SiO2 source and B2O3 source are prepared in a molar ratio of (1-6):1. After drying and granulating the mixed slurry, it is heat-treated at 450-900℃ for 1-4 hours to obtain an antibacterial retaining powder containing a rare earth oxide and borosilicate retaining network; in one preferred embodiment, the wet dispersion is performed using high-shear dispersion for 5-60 minutes, and a dispersant is added to improve the uniformity of the slurry, the dispersant including polyethylene glycol. In one preferred embodiment, the solid content of the mixed slurry is 10-40 wt%, and the particle size of the dried and granulated particles is 0.1-2 mm.

[0045] S2. Preparation of glaze slurry: The base glaze raw material is mixed with the antibacterial retaining powder and then ball-milled to obtain a glaze slurry for glazing; the ball-milling time is 4-18 hours; in one preferred embodiment, the solid content of the glaze slurry is controlled at 50-75%, and the viscosity is adjusted to meet the process requirements of spraying, dipping, or pouring glaze. In one preferred embodiment, the ball milling medium is alumina balls, and the ball-to-material ratio is 1-3; at 25°C, the viscosity of the glaze slurry is 500-3000 mPa·s.

[0046] S3. Glazing and Drying: The glaze slurry is applied to the surface of the ceramic body or bisque-fired body and dried. In one preferred embodiment, the drying temperature is 60-120℃. In one preferred embodiment, to facilitate the formation of a component gradient distribution in the thickness direction, a layered glazing method is adopted so that the antibacterial retaining component preferentially enters the glaze layer region closer to the substrate. In one preferred embodiment, the layered glazing includes first applying a base glaze layer containing the antibacterial retaining powder and drying it, and then applying a top glaze layer containing little or no antibacterial retaining powder and drying it. In one preferred embodiment, by controlling the solid content of the glaze slurry, the amount of glaze applied at one time, or the number of glazing applications, the thickness of the functional glaze layer after firing is 10-200μm.

[0047] S4. Glazing: The dried body is fired at 1180-1250℃ for 30-120 minutes and then cooled to obtain a functional glaze layer containing an antibacterial retaining phase.

[0048] S5. Constructing a self-cleaning photocatalytic phase: First, reduce the CeO2 / TiO2 composite powder to obtain CeO2. 2-x / TiO2 composite particles, specifically treated at 300-600°C for 0.5-2 hours under a hydrogen-containing protective atmosphere; in one preferred embodiment, x is 0.01-0.20. Subsequently, the CeO2... 2-x / TiO2 composite particles were added to a dispersion medium to prepare a dispersion, and the dispersion was coated onto the surface of the functional glaze layer and cured to allow CeO2 to form a glaze. 2-x / TiO2 composite particles form an enriched structure on the surface region of the functional glaze layer; in one preferred embodiment, the dispersion is an aqueous dispersion and further contains silica sol, which is a cationic silica sol; in one preferred embodiment, the curing temperature is 150-450℃ and the curing time is 0.5-2h; in one preferred embodiment, the surface region thickness reaches 50-1000nm by controlling the solid content of the dispersion, the amount of coating per coat, and the number of coats. In one preferred embodiment, the CeO2 in the dispersion... 2-x The solid content of the TiO2 composite particles is 0.1-5 wt%.

[0049] The CeO 2-x The TiO2 composite particles were prepared using a solution-phase colloidal seed deposition method, specifically including: (1) Preparation of CeO2 colloidal seeds: Prepare a CeO2 colloidal aqueous dispersion with a particle size of 5-80 nm, wherein the particle size is about 50 nm.

[0050] (2) Preparation of Ti source solution: Prepare a 0.1 mol / L Ti(SO4)2 aqueous solution, wherein the concentration of the Ti source solution is 0.05-0.5 mol / L.

[0051] (3) Deposition into a shell: Under 10℃ conditions, 20 mL of Ti(SO4)2 solution was pumped into 100 mL of CeO2 colloidal aqueous dispersion in about 2 h, and stirring was maintained to allow Ti(SO4)2 to hydrolyze in the dispersion system to generate titanium-containing hydrolysis products and deposit on the surface of CeO2 particles, thus obtaining CeO2 / TiO2 composite particle dispersion system;

[0052] (4) Solid-liquid separation and post-treatment: The obtained dispersion system is centrifuged, washed, and dried to obtain CeO2 / TiO2 composite particle powder; in one preferred embodiment, the thickness of the obtained TiO2 shell is about 5 nm. In one preferred embodiment, the CeO2 / TiO2 composite particle powder is heat-treated at 350-500℃ for 0.5-3 h. The CeO2 / TiO2 composite particle powder can be further reduced according to step S5 to obtain CeO2. 2-x / TiO2 composite particles. Example 1:

[0053] This embodiment provides a self-cleaning rare earth antibacterial ceramic material, the raw materials of which specifically include: 150g of silica powder, 90g of boric acid, 60g of CeO2 powder, 40g of La2O3 powder, 10g of Ag2O powder, 20g of CuO powder, and 10g of ZnO powder; a total of 970g of basic glaze raw materials and 30g of antibacterial retaining powder, wherein the basic glaze raw materials are composed of 420g of feldspar, 220g of quartz, 150g of kaolin, 110g of calcite, and 70g of talc; CeO2 powder... 2-x 10g of TiO2 composite particle powder; and dispersion raw materials for coating, including 485g of deionized water and CeO2. 2-x 10g of TiO2 composite particle powder, 50g of cationic silica sol with a solid content of 30wt%, and 5g of dispersant.

[0054] Prepared by the following method: S1. Preparation of antibacterial retaining powder: 60g of CeO2 powder, 40g of La2O3 powder, 150g of silica powder, 90g of boric acid, 10g of Ag2O powder, 20g of CuO powder, and 10g of ZnO powder were added to 900g of deionized water. After adding 3g of polyethylene glycol, the mixture was dispersed at high shear for 30min to obtain a mixed slurry. The mixed slurry was dried at 110℃ for 12h and then pulverized and granulated. The particle size of the granulated particles was controlled to be 0.3-1.0mm. The granulated particles were heat-treated at 700℃ for 2h, cooled, pulverized, and sieved to obtain the antibacterial retaining powder.

[0055] S2. Preparation of glaze slurry: Weigh a total of 970g of basic glaze raw materials, mix with 30g of antibacterial retaining powder obtained in S1, and add 540g of deionized water (to make the solid content of the glaze slurry 65wt%). Use alumina balls as the ball milling medium, with a ball-to-material ratio of 2, and ball mill for 10h to obtain the glaze slurry for glazing.

[0056] S3. Glazing and drying: Apply the glaze slurry obtained in S2 to the surface of the bisque-fired body. Control the amount of glaze applied in a single application so that the thickness of the functional glaze layer after firing is 60μm. Dry at 90℃ for 40min.

[0057] S4. Glazing: The dried body is fired at 1220℃ for 60 minutes and cooled to obtain a functional glaze layer containing an antibacterial retaining phase.

[0058] Pre-preparation steps of CeO2 / TiO2 composite particle powder: P1. Preparation of CeO2 colloidal seeds: Prepare 1000 mL of CeO2 colloidal aqueous dispersion with a CeO2 mass concentration of 20 g / L and a CeO2 particle D50 of 50 nm; P2. Preparation of Ti source solution: Prepare 200 mL of Ti(SO4)2 aqueous solution with a concentration of 0.1 mol / L; P3. Deposition: The system temperature was controlled at 10℃. The Ti(SO4)2 solution was pumped into the CeO2 colloidal dispersion at a rate of 1.67 mL / min with a stirring speed of 500 rpm for 120 min. After the addition was completed, stirring was continued for 60 min. P4. Solid-liquid separation and heat treatment: Centrifuge separation, wash three times with deionized water, and dry at 80℃ for 12h; heat treat the dried powder at 400℃ for 2h to obtain CeO2 / TiO2 composite particle powder.

[0059] S5. Construction of a self-cleaning photocatalytic phase: The CeO2 / TiO2 composite particle powder obtained in P4 was treated at 450℃ for 1 h under a protective atmosphere of 5% H2 and the remainder being N2 to obtain CeO2 / TiO2 composite particles. 2-x / TiO2 composite particle powder (x is 0.01-0.20); CeO 2-x 10g of TiO2 composite powder was added to 485g of deionized water, along with 50g of cationic silica sol (30wt% solid content). The mixture was mechanically stirred for 10min and then ultrasonically dispersed for 15min to obtain a dispersion. This dispersion was sprayed onto the surface of the functional glaze layer obtained in S4, with the dry base solid deposition amount controlled at 2g / m², and cured at 250℃ for 1h to allow CeO2 to form a cohesive glaze. 2-x / TiO2 composite particles form an enriched structure on the surface of the functional glaze layer, with the surface thickness controlled at 200 nm. Example 2:

[0060] The difference between this embodiment and Example 1 is that the molar ratio of SiO2 to B2O3 in S1 is approximately 1:1. Specifically, the silica powder in S1 is changed to 70g, and the boric acid is changed to 120g, while the remaining raw materials in S1 remain the same as in the steps; the antibacterial retaining powder in S2 is still added at 30g, while the rest remain the same. Example 3:

[0061] The difference between this embodiment and Embodiment 1 is that the molar ratio of SiO2:B2O3 in S1 is approximately 6:1. Specifically, the amount of silica powder in S1 is changed to 210g, and the amount of boric acid is changed to 55g, while the rest remain the same. Example 4:

[0062] The difference between this embodiment and Embodiment 1 is that the metal ion source in S1 uses a different salt type. Specifically, 10g of Ag2O powder is replaced with 12g of silver silicate powder, 10g of ZnO powder is replaced with 18g of zinc phosphate powder, and 20g of CuO powder remains unchanged; the rest remain the same. Example 5:

[0063] The difference between this embodiment and Embodiment 1 is that the rare earth oxide particles in S1 are CeO2 and Y2O3. Specifically, 40g of La2O3 powder is replaced with 40g of Y2O3 powder, while the rest remains the same. Example 6:

[0064] The difference between this embodiment and embodiment 1 is that the amount of antibacterial retaining powder added in S2 is adjusted to 5g, and the total amount of basic glaze raw materials is adjusted to 995g, so that the total amount of dry solid phase of the functional glaze layer is still 1000g; the rest remain the same. Example 7:

[0065] The difference between this embodiment and embodiment 1 is that the amount of antibacterial retaining powder added in S2 is adjusted to 60g, and the total amount of basic glaze raw materials is adjusted to 940g, so that the total amount of dry solid phase of the functional glaze layer is still 1000g; the rest remain the same. Example 8:

[0066] The difference between this embodiment and embodiment 1 is that CeO in S5... 2-x The amount of TiO2 composite powder is adjusted to 1g, the amount of deionized water in the dispersion formula is adjusted to 494g, and the amount of cationic silica sol remains unchanged at 50g; the rest remain the same. Example 9:

[0067] The difference between this embodiment and embodiment 1 is that CeO in S5... 2-x The amount of TiO2 composite powder was adjusted to 30g, and the amount of deionized water and cationic silica sol in the dispersion formula was adjusted to 465g and 60g respectively; the rest remained the same. Example 10:

[0068] The difference between this embodiment and embodiment 1 is that: in S5, the amount of dry base solid deposition is controlled to be 0.5 g / m², and the curing temperature is adjusted to 200℃ and the curing time is 1 h, so that the surface area thickness is controlled to be 50 nm; the rest remain the same. Example 11:

[0069] The difference between this embodiment and embodiment 1 is that: in S5, the amount of dry base solid deposition is controlled to be 10g / m², and the curing temperature is adjusted to 350℃ and the curing time is 1h, so that the surface area thickness is controlled to be 1000nm; the rest remain the same. Example 12:

[0070] The difference between this embodiment and Embodiment 1 is that S3 employs a layered glazing method and adjusts the glaze layer thickness. Specifically, a base glaze slurry containing 3wt% antibacterial retaining powder is first applied, resulting in a base glaze layer thickness of 120μm after firing; after the base glaze dries, a top glaze slurry without antibacterial retaining powder is applied, resulting in a top glaze layer thickness of 30μm after firing; after firing in S4, S5 is applied and cured, where CeO2 is present. 2-x The amount of TiO2 composite powder used remains 10g, and the surface thickness is controlled at 300nm; the rest remains the same.

[0071] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that step S5 is not performed, while the rest remains the same.

[0072] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that: no antibacterial retaining powder is added in S2, the total amount of basic glaze raw materials is 1000 g, and the rest are the same.

[0073] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that in S1, the amount of silica powder is 40 g and the amount of boric acid is 140 g, so that the molar ratio of SiO2:B2O3 is about 0.5:1, while the rest remain the same.

[0074] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that CeO in S5 2-x The amount of TiO2 composite powder used is 50 g, and the rest remains the same.

[0075] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that in S5, the amount of dry-based solid deposition was controlled to be 25 g / m³. 2 The surface thickness was controlled to 2000 nm, while the rest remained the same.

[0076] Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that the heat treatment temperature of P4 was adjusted to 650°C and the heat treatment time was 2 hours, while the rest remained the same.

[0077] Comparative Example 7 The difference between Comparative Example 7 and Example 1 is that the D50 of the CeO2 colloidal seed in P1 is 150 nm, while the rest remain the same.

[0078] Comparative Example 8 The difference between Comparative Example 8 and Example 1 is that the reduction treatment step is omitted in S5, and the CeO2 / TiO2 composite particle powder obtained in P4 is directly used to prepare the dispersion and coated and cured, while the rest remains the same.

[0079] Test methods 1. Antibacterial rate (%): Referring to JC / T 897-2014 "Antibacterial properties of antibacterial ceramic products", a quantitative bacterial solution was inoculated onto the surface of the glaze sample using the film-coating method and allowed to fully contact it. After incubation under specified temperature and time conditions, the bacterial solution was washed off and counted. The antibacterial rate was calculated by comparing it with the blank control.

[0080] 2. Antibacterial durability (%): Referring to JC / T 897-2014 "Antibacterial properties of antibacterial ceramic products", the samples were subjected to durability treatment according to the standard (such as friction or cleaning cycles in the specified manner), and the antibacterial rate after treatment was measured according to the same film inoculation and counting procedure. The antibacterial durability was calculated based on the results before and after treatment.

[0081] 3. Photocatalytic antibacterial activity (antibacterial rate / %): Referring to GB / T 23763-2009 "Evaluation of antibacterial properties of photocatalytic antibacterial materials and products", the bacterial solution was inoculated on the surface of the sample and treated under the specified ultraviolet irradiation conditions. Then, the viable bacteria were counted and the photocatalytic antibacterial rate was calculated by comparing with the blank control.

[0082] 4. Self-cleaning performance (methylene blue degradation rate / %): Referring to GB / T 23764-2009 "Test Method for Performance of Photocatalytic Self-cleaning Materials", a methylene blue solution was applied to the surface of the sample to form a contamination film. After irradiation under specified light conditions, the change in absorbance or equivalent characterization value of the contaminant residue was measured, and the degradation rate was calculated.

[0083] 5. Surface hydrophilicity (water contact angle / °): Refer to GB / T 30447-2013 "Method for measuring contact angle of nanofilms", drop a specified volume of water on the glaze surface of the sample and collect the droplet profile image, and calculate the static water contact angle by contact angle meter or image analysis method.

[0084] 6. Chemical corrosion resistance (grade): Refer to GB / T 3810.13-2016 "Test methods for ceramic tiles - Part 13: Determination of chemical corrosion resistance", after the sample surface is brought into contact with the specified chemical reagent under the specified conditions, it is cleaned and dried, and the chemical corrosion resistance grade is evaluated according to the degree of appearance change according to the standard rules.

[0085] Test Results The test results of Examples 1-12 and Comparative Examples 1-8 are shown in Table 1: Table 1

[0086] As shown in Table 1, the antibacterial rate and antibacterial durability were evaluated according to JC / T 897-2014. The durability treatment condition was 500 washes followed by testing. The antibacterial rate of Examples 1-12 was 96.0-99.9%, and the corresponding antibacterial durability was 90.0-98.0%. Among them, the antibacterial rate and antibacterial durability of Example 6 were 96.0% and 90.0%, respectively, and those of Example 7 were 99.9% and 97.0%, respectively. The antibacterial rate of Comparative Example 2 was 15.0%, and the antibacterial durability was 10.0%; the antibacterial rate of Comparative Example 3 was 99.7%, and the antibacterial durability was 70.0%.

[0087] The photocatalytic antibacterial rate was evaluated according to GB / T 23763-2009. The photocatalytic antibacterial rates of Examples 1-12 were 60.0%-99.9%, with Example 8 at 60.0%, Example 10 at 85.0%, and Examples 1, 9, and 12 at 99.8%-99.9%. Comparative Example 1 showed a rate of 20.0%, Comparative Example 6 at 40.0%, Comparative Example 7 at 55.0%, and Comparative Example 8 at 80.0%. The methylene blue degradation rate was evaluated according to GB / T 23764-2009. The rates of Examples 1-12 were 35%-95%, with Example 8 at 35%, Example 10 at 55%, Example 11 at 93%, and Example 9 at 95%; Comparative Example 1 showed a rate of 5%, Comparative Example 6 at 20%, Comparative Example 7 at 30%, and Comparative Example 8 at 60%. Corresponding to the degradation rate, the water contact angle was 8-48° within the example group, for example, 14° in Example 1, 8° in Example 9, 48° in Example 8, and 70° in Comparative Example 1.

[0088] According to GB / T 3810.13-2016, the chemical corrosion resistance rating was evaluated as follows: Examples 1, 3, 5, 6, 10, and 12 were GA / GLA / GHA; Examples 2, 4, 7, and 9 were GA / GLB / GHB; Example 11 was GB / GLB / GHB; Comparative Examples 3, 4, and 5 were GB / GLC / GHC; Comparative Examples 1, 2, and 6 were GA / GLA / GHA; and Comparative Examples 7 and 8 were GA / GLB / GHB.

[0089] In summary, regarding the antibacterial properties, the example groups maintained a high level overall and continued to do so after durability treatment, while samples lacking the antibacterial retaining phase showed a significant decrease. Regarding self-cleaning, the photocatalytic antibacterial rate, methylene blue degradation rate, and water contact angle of the example groups showed a consistent improvement trend, while the corresponding indicators decreased in comparative samples lacking surface construction steps or altering particle characteristics. Regarding chemical corrosion resistance, most groups maintained the GA / GLA / GHA or GA / GLB / GHB levels, while some comparative samples showed a decrease in grade, indicating that different ratios and surface construction conditions have a distinguishable impact on the chemical corrosion resistance grade.

[0090] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if these modifications and modifications of the invention fall within the scope of the claims and their equivalents, the invention is also intended to include these modifications and modifications.

Claims

1. A self-cleaning rare earth antibacterial ceramic material, characterized in that, It includes a ceramic substrate and a functional glaze layer formed on the surface of the ceramic substrate; the functional glaze layer includes an antibacterial retaining phase and a self-cleaning photocatalytic phase. The antibacterial holding phase comprises rare earth oxide particles, a metal ion source, and a borosilicate holding network. The rare earth oxide is selected from at least two of CeO2, La2O3, and Y2O3. The metal ion source is selected from at least one of silver, copper, and zinc. The borosilicate holding network is formed by sintering a SiO2 source and a B2O3 source. The self-cleaning photocatalytic phase includes CeO. 2-x / TiO2 composite particles, wherein CeO 2-x / TiO2 composite particles are enriched in the surface region of the functional glaze layer, and the surface region has a thickness of 50-1000 nm.

2. The self-cleaning rare earth antibacterial ceramic material according to claim 1, characterized in that, Based on the total dry-balance solid content of the functional glaze layer: the content of the antibacterial retaining phase is 0.5-6 wt%, and the CeO content is... 2-x The content of the TiO2 composite particles is 0.1-3wt%.

3. The self-cleaning rare earth antibacterial ceramic material according to claim 1, characterized in that, The molar ratio of SiO2 to B2O3 in the borosilicate holding network is (1~6):1, and the metal ion source is dispersed in at least one of metal oxide, metal silicate, metal borate, and metal phosphate and held by the borosilicate holding network.

4. The self-cleaning rare earth antibacterial ceramic material according to claim 1, characterized in that, The CeO 2-x The TiO2 composite particles have a core-shell or interpenetrating structure, and the TiO2 is anatase phase; the CeO2... 2-x The D50 of the / TiO2 composite particles is 5-80nm.

5. The self-cleaning rare earth antibacterial ceramic material according to claim 1, characterized in that, The functional glaze layer has a component gradient distribution along the thickness direction: the enrichment region of the antibacterial holding phase is located within the thickness range close to the ceramic matrix, and the CeO... 2-x The enrichment zone of the / TiO2 composite particles is located in the thickness range away from the ceramic matrix.

6. The self-cleaning rare earth antibacterial ceramic material according to claim 1, characterized in that, The functional glaze layer has a thickness of 10-200 μm, and its surface has a micro-nano composite morphology, which is composed of nano-sized CeO. 2-x / TiO2 composite particles together form a micron-sized glaze phase solidification framework.

7. A preparation process for the self-cleaning rare earth antibacterial ceramic material according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Preparation of antibacterial retaining powder: Rare earth oxides or their precursors, SiO2 source, B2O3 source and metal ion source are added to an aqueous medium and wet-mixed and dispersed to obtain a mixed slurry; the mixed slurry is dried and granulated, and then heat-treated at 450-900℃ for 1-4h to obtain antibacterial retaining powder containing a rare earth oxide and borosilicate retaining network; S2. Preparation of glaze slurry: After mixing the basic glaze raw materials with the antibacterial retaining powder, the mixture is ball-milled to obtain a glaze slurry for glazing. S3. Glazing and drying: Apply the glaze slurry to the surface of the ceramic body or bisque-fired body and dry it; S4. Glazing: The dried body is fired at 1180-1250℃ for 30-120 minutes, and after cooling, a functional glaze layer containing an antibacterial retention phase is obtained. S5. Constructing a self-cleaning photocatalytic phase: Coating the surface of the functional glaze layer with a CeO2-containing phase. 2-x The dispersion of / TiO2 composite particles was solidified, allowing CeO2 to form a solidified solution. 2-x / TiO2 composite particles form an enriched structure on the surface region of the functional glaze layer.

8. The preparation process according to claim 7, characterized in that, The aqueous medium in step S1 contains a dispersant, which includes polyethylene glycol; the ball milling time in step S2 is 4-18 hours.

9. The preparation process according to claim 7, characterized in that, The dispersion in step S5 also includes silica sol, which is a cationic silica sol; the curing temperature in step S5 is 150-450℃, and the curing time is 0.5-2h.

10. The preparation process according to claim 7, characterized in that, The CeO 2-x / TiO2 composite particles were obtained by reduction treatment to obtain CeO 2-x The structure, wherein the reduction treatment is performed at 300-600℃ for 0.5-2h under a hydrogen-containing protective atmosphere, and x is 0.01-0.20.

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