Description:FIELD OF THE INVENTION
The invention relates to environmentally sustainable nanocoatings composed of Ti₃C₂ MXene and SnO₂ quantum dots for air pollution mitigation. It specifically addresses applications in urban infrastructure for the degradation of airborne pollutants through advanced photocatalytic activity.
BACKGROUND OF THE INVENTION
References which are cited in the present disclosure are not necessarily prior art and therefore their citation does not constitute an admission that such references are prior art in any jurisdiction. All publications, patents and patent applications herein are incorporated by reference to the same extent as if each individual or patent application was specifically and individually indicated to be incorporated by reference.
Air pollution, particularly from nitrogen oxides (NOx) and sulfur oxides (SOx), poses significant threats to human health and the environment. Conventional air purification methods, such as catalytic converters and activated carbon filters, suffer from high maintenance costs, limited efficiency, and scalability challenges. The need for a passive, cost-effective, and scalable solution has led to the exploration of functional nanomaterials that can be integrated into urban infrastructure to degrade air pollutants continuously. A promising approach involves the development of a Ti3C2 MXene/SnO2 quantum dots (QDs) nanocomposite that can be coated onto road bricks, building walls, and other surfaces, enabling ambient-light-driven degradation of NOx and SOx through photocatalysis and adsorption mechanisms.
Several approaches have been explored for air pollution treatment, including:
Photocatalytic Materials: TiO2 and SnO2-based photocatalysts have been studied for NOX and SOX degradation, but their efficiency is often limited by poor charge separation and low absorption in the visible-light spectrum.
Adsorption-Based Systems: Activated carbon and metal-organic frameworks (MOFs) provide high surface area adsorption but lack a degradation mechanism, leading to saturation over time.
Catalytic Converters: Used in automotive applications, these require high temperatures and expensive platinum-group metals, making them unsuitable for passive environmental remediation.
Patent Search Findings: No known patents describe the use of Ti3C2 MXene combined with SnO2 QDs as a surface coating for air pollution treatment.
The proposed invention involves a Ti3C2 MXene/SnO2 QD nanocomposite synthesized through a combination of liquid-phase exfoliation and colloidal chemical methods. This nanocomposite is designed for coating on urban surfaces to passively degrade NOx and SOx through enhanced photocatalysis and adsorption. The Ti3C2 MXene serves as a highly conductive support that prevents charge recombination in the SnO2 QDs, while its large surface area enables effective adsorption of pollutant gases.
Unique Nanocomposite Combination: Unlike existing materials, these composite leverages both high charge conductivity and enhanced photocatalysis for continuous air purification.
Scalable Surface Coating: The application method allows integration into infrastructure without requiring complex installation or maintenance.
Room-Temperature Synthesis: The synthesis avoids high-temperature treatments, making it energy-efficient and environmentally friendly.
Several patents issued for nanocomposites as sensors but none of these are related to the present invention. Patent CN109613070B provides an ammonia gas sensor based on a two-dimensional MXene/SnO 2 heterojunction, a preparation process and an application, and belongs to the technical field of nanomaterials. The ammonia gas sensor is mainly composed of a gas sensing material and a heating substrate, and the working temperature is room temperature. The gas-sensitive material is coated on the surface of the heating substrate, and the coating thickness is 1 μm-100 μm; the gas-sensitive material is composed of a heterojunction composite nanomaterial formed by titanium carbide and tin dioxide. The invention adopts a hydrothermal method to obtain a new type of heterojunction composite nanomaterial, the raw material is convenient to obtain, the process of preparing the heterojunction is simple, and it is a two-dimensional semiconductor heterojunction preparation scheme with low equipment investment and simple process flow.
Another patent US20200001275A1 relates to an air purification filter comprising: a porous substrate comprising activated carbon; and a photocatalytic coating layer formed from a visible light-activated photocatalytic coating composition on the porous substrate comprising activated carbon, wherein an amount of the activated carbon ranges from 20% to 80% by weight based on an amount of the porous substrate comprising activated carbon, and the visible light-activated photocatalytic coating composition comprises a visible light active photocatalytic material, wherein the visible light active photocatalytic material comprises a porous first metal oxide; and a second metal particle supported on the porous first metal oxide, a second metal oxide particle, or both, wherein the first metal oxide is a tungsten oxide (WO3) and a second metal of the second metal particle and the second metal oxide particle is platinum (Pt), the visible light active photocatalytic material is formed into particles, the visible light-activated photocatalytic coating composition does not comprise an alcohol and a binder material, and the porous substrate comprising activated carbon is formed by attaching the activated carbon to or impregnating the activated carbon into a material comprising a woven or nonwoven fabric made of an organic fiber or inorganic fiber.
Another patent US20160144348A1 relates to a photocatalyst using a semiconductor-carbon nanomaterial core-shell composite quantum dot and a method for preparing the same, more particularly to a microparticle in which a semiconductor-carbon nanomaterial core-shell composite quantum dot is self-assembled using 4-aminophenol, capable of improving photoelectochemical response and photoconversion efficiency when used as a photocatalyst or a photoelectrode of a photoelectochemical device, a photoelectochemical device using the same and a method for preparing the same.
Another patent CN113025271A provides a Ti3C2TxA preparation method of MXene @ ZnO composite wave-absorbing material belongs to the technical field of electromagnetic wave-absorbing materials. The invention prepares accordion-shaped Ti3C2TxMXene powder, followed by preparation of Ti3C2TxMXene @ ZnO composite material precursor solution is subjected to solvothermal reaction with alkaline substances to obtain the required Ti with a sandwich structure3C2TxMXene @ ZnO composite material, wherein nano-scale ZnO nano-particles are uniformly distributed in Ti3C2TxMXene surface and interlayer, and the material has the advantages of light use weight, thin thickness, high absorption strength and wide effective absorption band; meanwhile, the whole preparation process is simple to operate and low in cost.
Another patent CN113683092B discloses a nitrogen-sulfur co-doped Ti3C2 - MXene nanosheet and a preparation method and application thereof. Ti3C2 - MXene is obtained by etching the ternary layered carbide of the MAX phase with hydrofluoric acid; Nitrogen-sulfur co-doped Ti 3 C 2 ‑MXene nanosheets were synthesized by a simple one-step method using thiourea as a source of heteroatoms. The material exhibits excellent peroxidase-like activity due to its unique two-dimensional layered structure, large specific surface area and abundant heteroatom catalytic active sites. The method of the invention can not only successfully dope two elements of nitrogen and sulfur on Ti 3 C 2 ‑MXene in one step, but also effectively overcome the cumbersome problem of step-by-step doping steps and the problem of secondary pollution caused by different doping sources, and endow Ti 3 C 2 ‑ MXene peroxidase activity can also solve the problems of high cost, long cycle and difficult operation of traditional uric acid detection methods. It has the advantages of convenience, speed, accuracy and efficiency, and low cost. Accurate quantitative detection in actual samples has broad application prospects.
OBJECTS OF THE INVENTION
Main object of the present invention is to develop a Ti₃C₂ MXene/SnO₂ quantum dot nanocomposite with enhanced photocatalytic properties for air pollutant degradation.
Another object of the present invention is to enable passive and continuous removal of NOₓ and SOₓ from urban environments using ambient light.
Another object of the present invention is to improve charge separation efficiency and reduce recombination through the conductive MXene substrate.
Another object of the present invention is to utilize the high surface area and adsorption capacity of MXene for increased interaction with pollutant gases.
Another object of the present invention is to create a scalable, low-energy, and eco-friendly coating method suitable for large-scale urban infrastructure applications.
SUMMARY OF THE INVENTION
This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention.
This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.
To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings.
The present invention provides a novel nanocomposite coating composed of Ti₃C₂ MXene and SnO₂ quantum dots, designed for passive air pollution mitigation in urban environments. The nanocomposite is synthesized through liquid-phase exfoliation of Ti₃C₂ MXene and colloidal chemical synthesis of SnO₂ QDs, followed by sonication-assisted integration. This material leverages the high conductivity and large surface area of MXene to enhance charge separation and pollutant adsorption, while SnO₂ QDs act as active photocatalysts under ambient light. When applied to urban surfaces such as buildings and roads, the coating facilitates the degradation of harmful gases like NOₓ and SOₓ into non-toxic byproducts, offering a sustainable, energy-efficient solution for improving urban air quality.
Herein enclosed a nanocoating material comprising titanium carbide (Ti₃C₂) MXene and tin oxide (SnO₂) quantum dots.
A process for the preparation of the nanocoating material as claimed in claim 1, wherein said process for the preparation of the nanocoating comprising the steps of:
Etching Ti3AlC2 MAX phase using a mixture of LiF and HCl to remove the Al layers;
resulting Ti3C2 MXene nanosheets are washed, centrifuged, and freeze-dried to obtain a stable dispersion;
stirring the solution at room temperature for 72 hours;
resulting SnO2 QDs are collected via centrifugation and redispersed in water;
mixing SnO2 QDs with Ti3C2 MXene in an aqueous solution under sonication to achieve uniform deposition; and
drying the composite and annealed at a low temperature to enhance bonding and stability.
The Thiourea is added as a sulfur source.
The SnO2 QDs generate electron-hole pairs under ambient light.
DETAILED DESCRIPTION OF THE INVENTION
The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.
It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a",” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
In addition, the descriptions of "first", "second", “third”, and the like in the present invention are used for the purpose of description only, and are not to be construed as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include at least one of the features, either explicitly or implicitly.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
In some embodiments of the present invention, provides a novel nanocomposite coating composed of Ti₃C₂ MXene and SnO₂ quantum dots, designed for passive air pollution mitigation in urban environments.
In some embodiments of the invention, the nanocomposite is synthesized through liquid-phase exfoliation of Ti₃C₂ MXene and colloidal chemical synthesis of SnO₂ QDs, followed by sonication-assisted integration.
In some embodiments of the invention, this material leverages the high conductivity and large surface area of MXene to enhance charge separation and pollutant adsorption, while SnO₂ QDs act as active photocatalysts under ambient light.
In some embodiments of the invention, when applied to urban surfaces such as buildings and roads, the coating facilitates the degradation of harmful gases like NOₓ and SOₓ into non-toxic byproducts, offering a sustainable, energy-efficient solution for improving urban air quality.
Herein enclosed a nanocoating material comprising titanium carbide (Ti₃C₂) MXene and tin oxide (SnO₂) quantum dots.
A process for the preparation of the nanocoating material as claimed in claim 1, wherein said process for the preparation of the nanocoating comprising the steps of:
Etching Ti3AlC2 MAX phase using a mixture of LiF and HCl to remove the Al layers;
resulting Ti3C2 MXene nanosheets are washed, centrifuged, and freeze-dried to obtain a stable dispersion;
stirring the solution at room temperature for 72 hours;
resulting SnO2 QDs are collected via centrifugation and redispersed in water;
mixing SnO2 QDs with Ti3C2 MXene in an aqueous solution under sonication to achieve uniform deposition; and
drying the composite and annealed at a low temperature to enhance bonding and stability.
The Thiourea is added as a sulfur source.
The SnO2 QDs generate electron-hole pairs under ambient light.
EXAMPLE 1
BEST METHOD
The proposed invention involves a Ti3C2 MXene/SnO2 QD nanocomposite synthesized through a combination of liquid-phase exfoliation and colloidal chemical methods. This nanocomposite is designed for coating on urban surfaces to passively degrade NOx and SOx through enhanced photocatalysis and adsorption. The Ti3C2 MXene serves as a highly conductive support that prevents charge recombination in the SnO2 QDs, while its large surface area enables effective adsorption of pollutant gases.
Synthesis Procedure:
Synthesis of Ti3C2 MXene: Ti3AlC2 MAX phase is selectively etched using a mixture of LiF and HCl to remove the Al layers. The resulting Ti3C2 MXene nanosheets are washed, centrifuged, and freeze-dried to obtain a stable dispersion.
Synthesis of SnO2 Quantum Dots: A wet-chemical colloidal synthesis is employed, where SnCl2·2H2O is dissolved in deionized water. Thiourea is added as a sulfur source, and the solution is stirred at room temperature for 72 hours. The resulting SnO2 QDs are collected via centrifugation and redispersed in water.
Formation of Ti3C2 MXene/SnO2 QD Nanocomposite: SnO2 QDs are mixed with Ti3C2 MXene in an aqueous solution under sonication to achieve uniform deposition. The composite is dried and annealed at a low temperature to enhance bonding and stability.
Flowchart Representation of the Synthesis Process:
1. Etching of Ti3AlC2 MAX phase → 2. Liquid-phase exfoliation of Ti3C2 MXene → 3. Colloidal synthesis of SnO2 QDs → 4. Sonication-assisted deposition of SnO2 QDs onto MXene → 5. Coating onto urban surfaces
Scientific Explanation for Air Pollution Treatment:
Photocatalytic Mechanism: SnO2 QDs generate electron-hole pairs under ambient light. The electrons react with oxygen to form superoxide radicals (O2⁻), while the holes react with water to form hydroxyl radicals (OH⁻), both of which degrade NOx and SOx into harmless byproducts.
Charge Separation Enhancement: The Ti3C2 MXene substrate prevents charge recombination, increasing the efficiency of the photocatalytic reaction.
Adsorption Properties: The high surface area and functional groups of MXene enhance NOx and SOx capture, allowing prolonged interaction with the active sites for degradation.
COMPARISON:
Aspect Proposed Method Photocatalytic TiO2 Activated Carbon Catalytic Converters
Active Mechanism Photocatalysis + Adsorption Photocatalysis Adsorption High-temperature Catalysis
Scalability High, applicable on urban surfaces Moderate Low Limited to vehicles
Energy Requirement Ambient light-driven UV light required None Requires high temperatures
Pollutant Removal NOx, SOx NOx NOx, SOx NOx, CO

, C , Claims:1. A nanocoating material comprising titanium carbide (Ti₃C₂) MXene and tin oxide (SnO₂) quantum dots.
2. A process for the preparation of the nanocoating material as claimed in claim 1, wherein said process for the preparation of the nanocoating comprising the steps of:
a) Etching Ti3AlC2 MAX phase using a mixture of LiF and HCl to remove the Al layers;
b) resulting Ti3C2 MXene nanosheets are washed, centrifuged, and freeze-dried to obtain a stable dispersion;
c) stirring the solution at room temperature for 72 hours;
d) resulting SnO2 QDs are collected via centrifugation and redispersed in water;
d) mixing SnO2 QDs with Ti3C2 MXene in an aqueous solution under sonication to achieve uniform deposition; and
e) drying the composite and annealed at a low temperature to enhance bonding and stability.
3. The process as claimed in claim 2, wherein Thiourea is added as a sulfur source.
4. The process as claimed in claim 2, wherein SnO2 QDs generate electron-hole pairs under ambient light.