WO2023147438A1

WO2023147438A1 - Dark catalytic material for decomposition of a volatile organic compound and filter containing the same

Info

Publication number: WO2023147438A1
Application number: PCT/US2023/061402
Authority: WO
Inventors: Shahzahan MIA; Ekambaram Sambandan; Bin Zhang; Shinya Kotake; Yoshie Satomi
Original assignee: Nitto Denko Corporation
Priority date: 2022-01-26
Filing date: 2023-01-26
Publication date: 2023-08-03

Abstract

The present disclosure relates to deactivation resistant catalytic materials for decomposing volatile organic compounds in the presence or absence of visible light or ultraviolet light. The catalytic materials comprise an active catalyst comprising a noble metal and a single-phase metal oxide and/or a single-phase metal oxide hydroxide disposed on a supporting material comprising multiple catalytic action sites. Filters comprising the catalytic materials are also described.

Description

DARK CATALYTIC MATERIAL FOR DECOMPOSITION OF A VOLATILE ORGANIC COMPOUND AND FILTER CONTAINING THE SAME

Inventors: Shahzahan Mia, Ekambaram Sambandan, Bin Zhang, Shinya Kotake, Satomi Yoshie

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/303,160, filed January 26, 2022, which is incorporated by reference herein in its entirety.

BACKGROUND

Unless otherwise indicated in the present disclosure, the details described in the present disclosure are not prior art to the claims in the present application and are not admitted to be prior art by inclusion in this section.

Volatile organic compounds (VOCs) are environmental toxins that may accumulate and pollute food service, transportation, healthcare, and hospitality sectors. VOCs are predominantly anthropogenic, organic compounds such as alcohols, aldehydes, acetates, aromatics, esters, ketones, alkanes, alkenes, and other compounds comprising carbon, oxygen, hydrogen, and halogens. An example of a VOC is formalin, a liquid solution of formaldehyde, which is used extensively in laboratories and hospitals. However, the exposure to airborne formaldehyde or formalin can have serious adverse health effects and may cause death.

Photocatalysts are often utilized to provide photocatalytic combustion which results in the removal of VOCs from the air. Photocatalysts require incident irradiation in the UV or visible region of the spectrum to be effective. However, this irradiation may not be available in dark areas, such as in ductless fume hoods, or where there is no power supply available for UV sources and, thus, limits the ability to decontaminate environments in these areas. Photocatalysts also suffer the disadvantage of catalytic deactivation caused by carbonization at the surface of the photocatalyst. Furthermore, the efficiency and effectiveness of a photocatalyst to completely oxidize carbon molecules in VOCs is generally enhanced at higher temperatures, typically in the range of 200 -C to 450 -C. Moreover, photocatalysts may require high concentrations of VOCs above 150 ppm which is not practical where concentrations of VOCs are often much lower than 50 ppm.

Thus, there is a need for improved catalysts capable of overcoming the limitations of current photocatalysts for the removal of VOCs.

SUMMARY

The catalytic material described herein may be used in the catalytic combustion of volatile organic compounds (VOCs) in low temperature and low light conditions. The present disclosure includes catalytic materials that provide for lower rates of deactivation or degradation of the catalytic material and, thus, remain active for longer periods of time. Furthermore, the catalytic materials described herein are capable of decomposing concentrations of formaldehyde below 15 ppm.

In some embodiments, a catalytic material for decomposing a VOC may comprise an active catalyst comprising: 1 ) a noble metal and a single-phase metal oxide, a singlephase metal hydroxide, or a combination thereof; and 2) a supporting material comprising a first catalytic action site and a second catalytic action site, wherein the active catalyst is disposed upon both the first catalytic action site and the second catalytic action site; wherein the catalytic material decomposes the volatile organic compound in the presence or absence of visible light or ultraviolet light.

In some embodiments, the single-phase metal oxide may be a single-phase crystalline oxide. In some embodiments, the single-phase metal hydroxide may be a solid amorphous phase metal hydroxide.

In some embodiments, the size of the active catalyst is less than 20 nm in diameter. In some embodiments the catalytic material comprising the active catalyst and the supporting material is less than 20 nm in diameter.

In some embodiments, the single-phase metal oxide may be a binary metal oxide (defined herein as MO2), wherein M comprises a metal, a transition metal, or a combination thereof. In some embodiments, the metal comprises Ti, Fe, Zr, Sn, Ce, or combinations thereof. In one embodiment, the single-phase metal oxide may comprise TiC>2, wherein TiC>2 comprises less than 100% anatase phase and greater than 90% anatase phase. In some embodiments, the active catalyst may comprise at least one pendant hydroxyl functional group. In some embodiments, the noble metal comprises Pt, Ag, Pd, Ru, Ir, or combinations thereof. In some embodiments, the noble metal wt% ranges from 0.1 to 10.

In some embodiments, the supporting material may comprise a halloysite nanotube. In some embodiments, the halloysite nanotube may have an inside wall and an outside wall, wherein the first catalytic action site is located on the inside wall of the halloysite nanotube, and the second catalytic action site is located on the outside wall of the halloysite nanotube. In some embodiments, the supporting material may comprise at least one hydroxyl functional group at the inner catalytic action site and at least one hydroxyl functional group at the outer catalytic action site of the supporting material.

In some embodiments, the weight ratio of the active catalyst to the supporting material is greater than 70% (e.g., 7:3) and less than 95% (e.g., 19:1 ). In some embodiments, the catalytic material does not lose more than 5% of initial performance after at least 72 hours in an environment with a concentration of the VOC greater than 5 ppm.

In many embodiments, the catalytic material decomposes 75% the VOC in the presence or absence of visible light or ultraviolet light, in less than 30 seconds. In some embodiments, the VOC may comprise formaldehyde.

In some embodiments, the catalytic material spontaneously produces active oxygen species.

In some embodiments, the catalytic material may further comprise a honeycomb ceramic substrate.

Some embodiments include a filter comprising a catalytic material. In some embodiments the catalytic material is dispersed or coated onto the honeycomb ceramic substrate to produce the filter, and the filter decomposes a VOC from an environment in the presence or absence of visible light or ultraviolet light.

These and other embodiments are described in greater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustrating an embodiment of a catalytic material. FIG. 2 is a graph depicting the performance of a filter comprising an embodiment of a catalytic material.

FIG. 3 is a graph depicting the performance of a filter comprising an embodiment of a catalytic material.

FIG. 4 is a graph depicting the performance of a filter comprising an embodiment of a catalytic material.

FIG. 5 is a graph depicting the performance of a filter comprising an embodiment of a catalytic material.

FIG. 6 is a graph depicting the performance of a filter comprising an embodiment of a catalytic material.

FIG. 7 is a graph depicting the performance of a filter comprising an embodiment of a catalytic material.

FIG. 8 is a graph depicting the performance of a filter comprising an embodiment of a catalytic material.

FIG. 9 is a graph depicting the performance of a filter comprising an embodiment of a catalytic material.

FIG. 10 is a graph depicting the performance of a filter comprising an embodiment of a catalytic material.

FIG. 11 is a graph depicting the performance of a filter comprising an embodiment of a catalytic material.

FIG. 12 is a graph depicting the performance of a filter comprising an embodiment of a catalytic material.

DETAILED DESCRIPTION

The present disclosure includes dark catalytic materials for degrading environmental toxins, such as a volatile organic compound (VOC), under ambient conditions without the use of a light source.

The term “volatile organic compound” or “VOC” as used herein means an environmental pollutant or toxin, such as, but not limited to, organic compounds such as alcohols, aldehydes, acetates, aromatics, esters, ketones, alkanes, alkenes, other hydrocarbons, and other compounds comprising carbon, oxygen, hydrogen, and halogens.

As used herein, when a compound, element, or material is referred to as being “catalytic”, the said compound, element, or material can degrade a VOC without exposure to an energetic radiation source, such as visible light or ultraviolet light, at ambient or subambient temperatures.

The term “deactivation” as used herein means the loss of catalytic activity, and/or the ability to degrade a VOC over time.

The term “carbonyl group” as used herein means a functional group composed of a carbon atom double-bonded to an oxygen atom.

The term “hydroxyl group” as used herein means a functional group with the chemical formula OH and is composed of one oxygen (O) atom covalently bonded to one hydrogen (H) atom.

The term “bond” or “bonded” as used herein means a chemical bond between two atoms.

The term “chemisorb”, or “chemisorption” means a process in which one substance is adsorbed onto the surface of another substance by means of chemical rather than physical bonding.

Use of the term “may” or “may be” should be construed as shorthand for “is” or “is not” or, alternatively, “does” or “does not” or “will” or “will not,” etc. For example, the statement “the single-phase metal oxide may comprise TiC ” should be interpreted as, for example, “In some embodiments, the single-phase metal oxide comprises TiC>2,” or “In some embodiments, the single-phase metal oxide does not comprise TiC>2.”

The current disclosure includes a catalytic material comprising an active catalyst. In some embodiments, the active catalyst comprises a noble metal and a single-phase metal oxide or single-phase metal hydroxide. In some embodiments, the catalytic mater comprises the active catalyst and a supporting material. In some embodiments, the supporting material may have a first catalytic action site and a second catalytic action site, wherein the active catalyst is disposed upon, or impregnated within, both the first catalytic action site and the second catalytic action site. Some examples include the use of the catalytic material for the removal of VOCs. In some embodiments, the VOC may be formaldehyde (also referred to herein as HCHO or FA). In some examples, the catalytic material displays VOC removal qualities without the need to be activated by visible light or UV radiation and may be useful in the removal of VOCs in low temperature environments. In some embodiments, the catalytic material may be described as a dark catalytic material, meaning that it exhibits VOC removal qualities without the need for visible light or UV radiation. The present disclosure describes a catalytic material that permits spontaneous chemisorption of atmospheric oxygen and improves the formation of an active oxygen species (e.g., super oxide radicals) to facilitate the oxidation of VOCs. In some embodiments, the catalytic material spontaneously produces the active oxygen species.

In some embodiments, wherein the catalytic material is in proximity with a VOC (e.g., formaldehyde), a reaction is initiated that results in the formation of reactive radical species. In another embodiment, the active catalyst may chemisorb oxygen molecules. The chemisorbed oxygen molecules may be reduced by the electrons from the noble metal (e.g., by transfer of an electron from the noble metal to the oxygen molecule). The reduction of the chemisorbed oxygen molecules initiates a reaction that generates a reactive radical species. The reactive radical species facilitates the decomposition and oxidation of formaldehyde by attacking the carbon atom of the formaldehyde carbonyl group. Water vapor (H2O) and carbon dioxide (CO2) are the harmless byproducts of the degradation and oxidation of VOCs.

In a preferred embodiment, the single-phase metal oxide may comprise TiO2. In another embodiment, the single-phase metal oxide may comprise TiO2 and at least one pendant hydroxyl functional group. The hydroxyl functional groups may interact with the oxidized VOC to chemisorb H2O and CO2 on the surface of the active catalyst. The chemisorbed H2O and CO2 molecules on the surface of the catalyst spontaneously desorb during the catalytic cycle. In some embodiments, the interaction of the hydroxyl functional group on the metal oxide with the oxidized volatile organic species may be the overall reaction rate determining step. The catalytic activity principle of the catalytic material as described herein is hypothesized in FIG 1 . In some embodiments, the catalytic material may comprise an active catalyst comprising a noble metal and a single-phase metal oxide or single-phase metal hydroxide. In some embodiments, the active catalyst may comprise a noble metal and a single-phase metal oxide. In some embodiments, the active catalyst may comprise a noble metal and a single-phase metal hydroxide. In some embodiments, the active catalyst may comprise a noble metal and a single-phase metal oxide and a single-phase metal hydroxide. In some embodiments, the noble metal is supported upon the singlephase metal oxide or single-phase metal hydroxide. In some embodiments, the singlephase metal hydroxide is a solid amorphous phase metal hydroxide. In some embodiments, the single-phase metal oxide is a single-phase crystalline oxide. In some embodiments, the single-phase metal oxide is a binary metal oxide. The binary metal oxide may be a single-phase n-type semiconductor designated as MO2, wherein M is a metal, a transition metal, or a combination thereof. In some embodiments, the transition metal comprises Ti, Fe, Zr, Sn, Ce, or a combination thereof. In some embodiments, the single-metal oxide comprises TiC>2, wherein TiC>2 comprises about 90-100% anatase phase, about 2.5-97.5%, about 5-95%, about 10-90%, about 15-85%, or about 20-80% anatase phase or any percentage in a range bounded by any of these values; and the rutile phase can be about 0-10%, about 2.5-97.5% about 5-95%, about 10-90%, about 15-85%, or about 20-80% rutile phase, or any percentage in a range bounded by any of these values. These single-phase metal oxides are characterized by the ability to easily exchange electrons which facilitates the changing of their oxidation state. A non-limiting example of a suitable single-phase metal oxide can include, but is not limited to, a TiC>2 mixture sold under the brand name P25 (83% Anatase TiC>2 + 17% Rutile TiC ) sold by Evonik (Parsippany, NJ, USA).

In some embodiments, the single-phase metal oxide of the catalytic material may be doped. In other embodiments, the single-phase metal oxide comprises a Zn doped MO2 oxides, a Nb⁵⁺ doped MO2 oxide, or a Ta⁵⁺ doped MO2 oxide. In some embodiments, the dopant concentration may be about 0.0001 wt%, about 0.0001 -0.01 wt%, about 0.01 - 0.05, about 0.05-0.10 wt% about 0.1 -1 wt%, about 1 -2.5 wt%, about 2.5-5 wt%, about 5- 7.5 wt%, about 7.5-10 wt%, about 10-12.5 wt%, about 12.5-15 wt%, about 15-17.5 wt%, about 17.5-20 wt%, or about 0.01 wt%, about 0.5 wt%, about 0.1 wt%, about 10 wt%, about 12.5 wt%, about 15.0 wt%, about 17.5 wt%, about 20.0 wt% of the catalytic material, or any wt% in a range bounded by any of these values. In some embodiments, the active catalyst may comprise at least one hydroxyl functional group on a surface of the active catalyst.

In various embodiments, the noble metal comprises Pt, Ag, Pd, Ru, Ir, their oxides and/or hydroxides, or combinations thereof. In some embodiments, the noble metal comprises transition metals, their oxides and/or hydroxides. In a preferred embodiment, the noble metal may comprise platinum (Pt) or its oxide and/or hydroxide. In some embodiments, the noble metal may be chosen from different groups of elements including a transition metal and a noble metal or their respective oxides and hydroxides. In some embodiments the noble metal wt% ranges from about 0.01 to about 15. In another embodiment, the noble metal (such as Pt) wt% may be about 0.01 -0.05 wt%, about 0.05- 0.10 wt% about 0.1 -1 wt%, about 1 -2.5 wt%, about 1 -4 wt%, about 2-3 wt%, about 2.5-5 wt%, about 5-7.5 wt%, about 7.5-10 wt%, about 10-12.5 wt%, about 12.5-15 wt%, about 15-17.5 wt%, about 17.5-20 wt%, or about 0.01 wt%, about 0.05 wt%, about 0.1 wt%, about 1 wt%, about 5 wt%, about 10 wt%, about 12 wt%, about 15 wt%, of the catalytic material, or a wt% in a range bounded by any of these values.

Some embodiments include a catalytic material. In some embodiments, the catalytic material may comprise a supporting material comprising a first catalytic action site and a second catalytic action site. In some embodiments, the supporting material may be described as a promotor. In some embodiments, the supporting material may comprise a tube structure with an inside wall with an inner diameter and an outside wall with an outside diameter. In some embodiments, the tube structure is a nanotube. A non-limiting example of a suitable supporting material can include, but is not limited to, halloysite clay material sold by Sigma-Aldrich (St. Louis, MO, USA). In some embodiments, the supporting material may comprise halloysite. In some embodiments, the supporting material may comprise halloysite nanotubes. In some embodiments, the first catalytic action site is located on an inside wall of the halloysite nanotube, and the second catalytic action site is located on an outside wall of the halloysite nanotube.

In some embodiments, the active catalyst is disposed upon (or impregnated within) both the first catalytic action site and the second catalytic action site. In some embodiments, the inner diameter of the tube structure is 20 nm to 40 nm. In some embodiments, the size of the active catalyst may be less than 20 nm in diameter and may enter the inside wall of the supporting material. In some embodiments, the size of the active catalyst may be less than about 20 nm, less than about 15 nm, less than about 10 nm, less than about 5 nm, or about 3 nm in diameter. In some embodiments, the size of the single-phase metal oxide or single-phase hydroxide is less than about 20 nm, less than about 15 nm, less than about 10 nm, less than about 5 nm, or about 3 nm in diameter.

In some embodiments, both the inside wall and the outside wall of the tube structure, such as a halloysite nanotube, facilitates the dispersion, support, or impregnation of the active catalyst. In some embodiments, such dispersion, support, or impregnation of the active catalyst facilitates exposure to a higher number of catalytic action sites for VOC decomposition. In some embodiments, the only catalytic action site is located on the outside wall of the supporting material. In some embodiments, the only catalytic action site is located on the inside wall of the supporting material. In some embodiments, the supporting material may comprise at least one hydroxyl functional group. In some embodiments, both the inner catalytic action site located at the inside wall and the outer catalytic action site located at the outside wall contain at least one hydroxyl functional group, which may be readily available for interaction with oxidized VOC. In some embodiments, the additional hydroxyl functional groups may accelerate the rate determining step of VOC oxidation. In some embodiments, such acceleration may improve the catalytic efficiency of the catalyst.

In some embodiments, the active catalyst/supporting material weight ratio is greater than 70% and less than 95%. In another embodiment, the active catalyst (such as TiO2, TiO2:ZrO2, ZrO2, Fe(OH)s, or a combination thereof) can be about 65 wt% to about 100 wt%, about 70 wt% to about 80 wt%, or about 80 wt% to about 90 wt% of the weight of the catalytic material. In some embodiments, TiC , is used in these weight percentages. In some embodiments, TiO2:ZrO2, is used in these weight percentages. In some embodiments, ZrC>2, is used in these weight percentages. In some embodiments, Fe(OH)3, is used in these weight percentages.

In some embodiments, the support material (such as halloysite) may be about 0 wt% to about 35 wt%, about 10 wt% to about 20 wt%, or about 20-30 wt% of the weight of the catalytic material.

In many embodiments, the VOC comprises formaldehyde. The presence of formaldehyde generally occurs within a closed environment. Formaldehyde is often found in gas stoves and open fireplaces and is used in the manufacturing of many household items, such as furniture, glues, paints, and cosmetics. The need to remove formaldehyde from air is driven by its inherent toxicity toward human health. For example, when formaldehyde is present in the air at levels exceeding 0.1 ppm, some individuals can experience adverse effects such as burning sensations, watery eyes, coughing, and skin irritation. In some embodiments, the catalytic material may decompose or oxidize concentrations of formaldehyde of less than about 20 ppm. In some embodiments, the catalytic material may decompose or oxidize concentrations of formaldehyde of less than less than about 15 ppm, less than about 10 ppm, less than about 5 ppm, or less than about 2 ppm.

In some embodiments, the catalytic material decomposes at least 75% of the VOC in the presence or absence of visible light or ultraviolet light, in less than 30 seconds. In some embodiments, the catalytic material decomposes at least 75% of the VOC in the presence or absence of visible light or ultraviolet light, in less than 5 seconds. In some embodiments, the catalytic material decomposes at least 80% of the VOC in the presence or absence of visible light or ultraviolet light, in less than 30 seconds. In some embodiments, the catalytic material decomposes at least 80% of the VOC in the presence or absence of visible light or ultraviolet light, in less than 5 seconds. In some embodiments, about 0.5 mg to about 10 mg of the catalytic material is capable of removing at least 75% of the VOC in less than 30 seconds in the presence or absence of visible light or ultraviolet light. In some embodiments, about 10 mg to about 50 mg of the catalytic material is capable of removing at least 80% of the VOC in less than 30 seconds in the presence or absence of visible light or ultraviolet light.

Any suitable method may be used to evaluate the catalytic activity of the embodiments of the present disclosure and the decomposition of formaldehyde. One method of determining whether a catalytic material may decompose concentrations of formaldehyde over time is by measuring the decrease or percentage loss of the formaldehyde concentration (based on the difference in the concentration of formaldehyde after exposure to the catalytic material to the initial formaldehyde concentration) over time. In one embodiment, degradation of formaldehyde is analyzed by injecting a mixture of formaldehyde and methanol gases into an in-house built single pass set-up chamber reactor and measuring the concentration of formaldehyde. The injection exposes the formaldehyde to the catalytic material and the oxidation reaction occurs. At 15-minute intervals, gas is collected from the outlet of the set-up chamber reactor for analysis of formaldehyde ppm and methanol ppm. Analysis of the concentration of formaldehyde can be performed by a large-volume injection system, e.g., a liquid chromatography-mass spectrometry (LC-MS). As evidenced by the results in FIGs. 2-1 1 below, the concentration of formaldehyde decreases when the catalytic material is introduced.

Because the air being circulated indoors is generally used for respiration, it is desirable to have the temperature of the indoor air to remain the relatively consistent or constant. Thus, an advantage of the present disclosure is the ability of the catalytic material to decompose VOCs at or near ambient temperatures, or room temperature. Significant advantages can also be realized by the present disclosure where the costs associated with operating such a catalytic system are reduced because the atmosphere would not need to be heated. It is believed that the catalytic material decomposes the VOC at temperatures less than 40 -C and greater than 10 -C. In some embodiments, the decomposition resistant catalytic materials described herein decompose the VOCs at about 10-15 ^QC, about 15-20 ^QC, about 20-25 ^QC, about 25-30 ^QC, about 30-35 ^QC, about 20-35 -C, about 35-40 -C, or any temperature in a range bounded by any of these values.

The catalytic process, or the decomposition and oxidation of VOCs, described herein is not limited by environmental factors such as radiation in the electromagnetic spectrum, including ultraviolet light, visible light, and near-infrared light to activate the catalytic material. In an embodiment, the catalytic material may decompose the VOC in the absence of a source of light, wherein the amount of the source of light is less than or equal to about 0.5 lumens, less than or equal to about 0.1 lumens, or about 0 lumens. In another embodiment, the catalytic material decomposes the VOC in the absence of ultraviolet irradiation, wherein the intensity of the ultraviolet irradiation is less than or equal to about 0.5 mW/cm², less than or equal to about 0.1 mW/cm², or about 0 mW/cm².

Any suitable method may be used to evaluate the deactivation performance of a catalytic material. One method used to analyze the decomposition of VOCs is performed by monitoring the formation of byproducts in real-time with a proton-transfer-reaction mass spectrometer (PTR-MS). In another embodiment, determining formaldehyde degradation by measuring the formation of carbon dioxide (CO2), or percentage increase of the concentration of CO2, the byproduct of the degradation and oxidation of formaldehyde, is a potential way to determine the catalytic material’s properties with respect to deactivation of the VOC. In some examples, the formation of CO2 (based on the difference in the amount of carbon dioxide formed to initial formaldehyde concentration over time) may be about 0% to about 100%, about 0-10%, about 10-20%, about 20-30%, about 30-40%, about 40-50%, about 50-60%, about 60-70%, about 70- 80%, about 80-90%, about 90-100%, or at least about 65%, at least about 70%, at least about 75%, at least about 80%, or about 82%, or about 83%, or about 84%. A catalytic material may be characterized with respect to its performance in a deactivation test, such as the deactivation of formaldehyde. During the measurements, a mixture 1 ppm formaldehyde is injected into an in-house built single pass set-up chamber reactor with a total flow of 600 mL/min. At 15-minute intervals, gas is collected from the outlet of the setup chamber reactor for measurement of the amount of carbon dioxide. Analysis of the concentration of CC can be performed by a large-volume injection system, e.g., a gas chromatograph/barrier discharge ionization detector (GC-BID). The time measurements of the deactivation of formaldehyde and/or formation of CO2, can be from about 1 minute to about 20 hours, about 1 -5 min, about 5-15 min, about 15-30 min, about 30-60 min, about 60-120 min, about 120-240 min, about 2-5 h, about 4-6 h, about 4-6 h, about 5-10 h, about 10-20 h, or any time period that is bound by these ranges. In many embodiments, the catalytic material has a deactivation lifetime of at least about 900 min, at least about 900-1000 min, at least about 1000-1100 min, at least about 1100-1200 min, or greater than 1200 min. In other embodiments, the catalytic material does not lose more than 5% of initial performance after at least 72 hours in an environment with a concentration of the VOC greater than 5 ppm. In other embodiments, the catalytic material does not lose more than 10% of initial performance after at least 72 hours in an environment with a concentration of the VOC greater than 1 ppm. The performance of the catalytic materials and the increase in the formation of CO2 and the decrease of formaldehyde (FA) are summarized in FIGs. 2-11 .

In some embodiments, the catalytic material may further comprise a metal hydroxide in a solid amorphous phase. In some embodiments, the size of the metal hydroxide is less than 20 nm. In some embodiments, the metal hydroxide may be Fe(OH)₃.

In some embodiments, the catalytic material may include a ceramic substrate material, wherein ceramic substrate is a honeycomb ceramic substrate. Some embodiments include a filter comprising the catalytic materials described herein and the substrate material. In some embodiments, the filter may remove or decompose at least 75% of a VOC from an environment in the presence or absence of visible light or ultraviolet light, in less than 30 seconds. In some embodiments, the filter may remove or decompose at least 80% of the VOC in the presence or absence of visible light or ultraviolet light, in less than 5 seconds. In some embodiments, the filter may comprise a 3-stage filter comprising three (3) filters, wherein the 3-stage filter is able to remove greater than 90% of the VOC in the presence or absence of visible light or ultraviolet light, in less than 30 seconds. In some embodiments, the filter may comprise a 4-stage filter comprising four (4) filters, wherein the 4-stage filter is able to remove greater than 90% of the VOC in the presence or absence of visible light or ultraviolet light, in less than 30 seconds.

In some embodiments, the catalytic material may be loaded on 1 cm x 1 cm honeycomb ceramic substrate to form the filter. In some embodiments, the catalytic material may be loaded on 5 cm x 5 cm honeycomb ceramic substrate to form the filter. The honeycomb ceramic substrate may need to be cleaned with isopropanol, acetone, and water before loading the catalytic material on the ceramic substrate to form the filter. In some embodiments, the filter may need to calcine at 150 °C or 400 °C before loading to a continuous VOC flow chamber reactor. In some embodiments, the flow of VOC chamber reactor had a VOC concentration of less than 2 ppm. The concentration of the VOC was measured before and after passing through the catalytic filter by gas chromatograph (GC). In some embodiments, the catalytic material was tested in a four stage unit evaluation system. The unit evaluation system contained at least four 5 cm x 5 cm honeycomb ceramic filters. In some embodiments, the VOC was decomposed by the catalytic material in each stage of the unit evaluation system. In some embodiment, the concentration inlet VOC was ~5 ppm. The concentration of inlet VOC and VOC after each stage was measured by LC-MS. As can be seen from the results in FIG. 12 below, the concentration of formaldehyde was reduced to less than 0.01 ppm with 3 filters.

All of the above U.S. patents, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification, are incorporated herein by reference in their entirety. Unless otherwise indicated, all numbers expressing quantities of ingredients, properties, such as, molecular weight, reaction conditions, and so forth used in the specifications and embodiments are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached embodiments are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, and not as an attempt to limit the application of the doctrine of equivalents, to the scope of the embodiments, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying conventional and ordinary rounding techniques.

For the processes and/or methods disclosed, the functions performed in the process and methods may be implemented in differing order, as may be indicated by context. Furthermore, the outlined steps and operations are only provided as examples and some of the steps and operations may be optional, combined into fewer steps and operations, or expanded into additional steps and operations.

This disclosure may sometimes illustrate different components contained within, or connected with, other different components. Such depicted architectures are merely examples, and many other architectures can be implemented to achieve the same or similar functionality.

The terms used in this disclosure and in the appended embodiment, (e.g., bodies of the appended embodiments) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including, but not limited to,” the term “having” should be interpreted to “having at least”, the term “includes” should be interpreted as “includes, but not limited to,” etc. in addition, if a specific number of elements is introduced, this may be interpreted to mean at least the recited number, as may be indicated by context (e.g., the bare recitation of “two recitations”, without other modifiers, means at least two recitations or two or more recitations). As used in this disclosure, any disjunctive word and/or phrase presenting two or more alternative terms should be understood to contemplate the possibilities of including one of those terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”. Similarly, the phrase “A and/or B” will be understood to include the possibilities of “A” or “B” or “A and B”. The terms “a”, “an”, “the”, and similar referents used in the context of describing the present disclosure (especially in the context of the following embodiments) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples, or representative language (e.g., “such as” or “for example”) provided herein is intended merely to better illustrate the present disclosure and does not pose a limitation on the scope of any embodiments. No language in this specification herein shall be construed as indicating any non-embodied element essential to the practice of the present disclosure.

Groupings of alternative elements or embodiments disclosed herein are not to be construed as limitations. Each group member may be referred to and embodied individually or in any combination with other members of the group or other elements found herein. It is anticipated that one or more members of a group may be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is deemed to contain the group as modified, thus fulfilling the written description of all Markush groups used in the appended embodiments.

Certain embodiments are described herein, including the best mode known to the inventors for carrying out the present disclosure. Of course, variations on these described embodiments, will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventors intend for the present disclosure to be practiced otherwise than specifically described herein. Accordingly, the embodiments are permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is contemplated unless otherwise indicated herein or otherwise clearly contradicted by context. In closing, it is to be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments. Therefore, by way of example, but not of limitation, alternative embodiments may be utilized in accordance with the teachings herein. Henceforth, the embodiments are not limited to the embodiments precisely as shown and described herein.

Examples of non-limiting embodiments are described below.

EMBODIMENTS Embodiment 1. A catalytic material for decomposing a volatile organic compound comprising: an active catalyst comprising a noble metal and a single-phase metal oxide or single-phase metal hydroxide; and a supporting material comprising a first catalytic action site and a second catalytic action site, wherein the active catalyst is disposed upon both the first catalytic action site and the second catalytic action site; wherein the catalytic material decomposes the volatile organic compound in the presence or absence of visible light or ultraviolet light.

Embodiment 2. The catalytic material of embodiment 1 , wherein the singlephase metal oxide is a single-phase crystalline oxide.

Embodiment 3. The catalytic material of embodiment 1 , wherein the singlephase metal oxide is a MO2 single-phase n-type semiconductor.

Embodiment 4. The catalytic material of embodiment 3, wherein M comprises a metal, transition metal, or combinations thereof.

Embodiment 5. The catalytic material of embodiment 4, wherein the transition metal comprises Ti, Fe, Zr, Sn, Ce, or combinations thereof.

Embodiment 6. The catalytic material of embodiment 5, wherein the singlemetal oxide comprises TiC>2, wherein TiC>2 comprises less than 100% anatase phase and greater than 90% anatase phase.

Embodiment 7. The catalytic material of embodiment 1 , wherein the size of the active catalyst is less than 20 nm.

Embodiment 8. The catalytic material of embodiment 1 , wherein the active catalyst comprises at least one pendant hydroxyl functional group.

Embodiment 9. The catalytic material of embodiment 1 , wherein the noble metal comprises Pt, Ag, Pd, Ru, Ir, or combinations thereof.

Embodiment 10. The catalytic material of embodiment 1 , wherein the noble metal wt. % ranges from 0.1 to 10.

Embodiment 11. The catalytic material of embodiment 1 , wherein the supporting material comprises a halloysite nanotube having an inside wall and an outside wall, wherein the first catalytic action site is located on the inside wall of the halloysite nanotube, and the second catalytic action site is located on the outside wall of the halloysite nanotube. Embodiment 12. The catalytic material of embodiment 1 , wherein the supporting material comprises at least one hydroxyl functional group at the first catalytic action site and at least one hydroxyl functional group at the second catalytic action site of the supporting material.

Embodiment 13. The catalytic material of embodiment 1 , wherein the active catalyst/supporting material weight ratio is greater than 70% and less than 95%.

Embodiment 14. The catalytic material of embodiment 1 , wherein the singlephase metal hydroxide is a solid amorphous phase metal hydroxide.

Embodiment 15. The catalytic material of embodiment 1 further comprising a honeycombed ceramic support.

Embodiment 16. The catalytic material of embodiment 1 , wherein the catalytic material decomposes 75% of the volatile organic compound in the presence or absence of visible light or ultraviolet light, in less than 30 seconds.

Embodiment 17. The catalytic material of embodiment 1 , wherein the catalytic material spontaneously produces active oxygen species.

Embodiment 18. The catalytic material of embodiment 1 , wherein the volatile organic compound comprises formaldehyde.

Embodiment 19. The catalytic material of embodiment 1 , wherein the catalytic material does not lose more than 5% of initial performance after at least 72 hours in an environment with a concentration of the volatile organic compound greater than 5 ppm.

Embodiment 20. A filter comprising: a catalytic material as in embodiments 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18, or 19 dispersed on the filter, wherein the filter decomposes a volatile organic compound from an environment in the presence or absence of visible light or ultraviolet light.

EXAMPLES

It has been discovered that the catalytic materials described herein have improved performance as compared to other catalytic materials for decomposing a VOC. The benefits are further demonstrated by the following examples, which are intended to be illustrative of the disclosure but are not intended to limit the scope or underlying principles in any way. The following examples are synthesis procedures of many embodiments of the catalytic materials described herein:

Synthesis Procedures

Example 1(a). Synthesis of 2.65%Pt-Na, B/Halloysite: 2.0 g of halloysite nanotubes were dispersed in 10 mL water and probe sonicated for 10 min at 80% intensity (output energy -6000J) to disperse the Halloysite in water. The dispersion was transferred to a 250 mL beaker and additional 40 mL water was added. After 30 min of vigorous stirring, 2.65 wt% Pt ions were added to the solution. The stirring was continued for another 60 min to impregnate the Pt on Halloysite. The surface Pt-ions were reduced using a NaBH4 and NaOH mixture solution. After 30 min, the solid Pt-Na, B/Halloysite were separated using centrifugation and washed with water to remove the unreacted Pt ions and NaBH4. The inorganic powder sample was dried at 105 -C for 2 h.

Example 1(b). Synthesis of 2.65%Pt-Na, B/Anatase TiO2: 2.0 g of single-phase anatase TiO2 nanoparticles (5nm) were dispersed in 10 mL water and probe sonicated for 10 min at 80% intensity (output energy -6000J) to disperse the anatase TiC>2 in water. The dispersion was transferred to a 250 mL beaker and additional 40 mL water was added. After 30 min vigorous stirring, 2.65 wt% Pt ions were added to the solution. The stirring was continued for another 60 min to impregnate the Pt on anatase TiC>2 surface. The surface Pt-ions were reduced using a NaBH4 and NaOH mixture solution. After 30 min, the solid Pt-Na, B/Anatase TiO2 were separated using centrifugation and washed with water to remove the unreacted Pt ions and NaBH4. The inorganic powder sample was dried at 105 ^QC for 2 h.

Example 1(c). Synthesis of 2.65%Pt-Na, B/(90%TiO2 + 10%Halloysite): 1.8 g of single-phase TiO2 (anatase) were mixed with 0.2 g of Halloysite clay materials. The mixture was prepared by an acoustic sonication mixer, which creates good contact of single-phase TiO2 and Halloysite. 10 mL water was added to the powder mixer and probe sonicated for 10 min at 80% intensity (output energy -6000J) to disperse the TiC>2- Halloysite mixture in water. The dispersion was transferred to a 250 mL beaker and additional 40 mL water was added. After 30 min vigorous stirring, 2.65 wt% Pt ions were added to the solution. The stirring was continued for another 60 min to impregnate the Pt on TiO2-Halloysite. The surface Pt-ions were reduced using a NaBH4 and NaOH mixture solution. After 30 min, the solid Pt-Na, B/(TiO2+Halloysite) were separated using centrifugation and washed with water to remove the unreacted Pt ions and NaBH4. The inorganic powder sample was dried at 105 -C for 2 h.

Example 1 (d). Synthesis of 2.65%Pt-Na, B/(80%TiO2 + 20%Halloysite): 1.6 g of single-phase TiC>2 (anatase) were mixed with 0.4 g of Halloysite clay materials. The mixture was prepared by an acoustic sonication mixer, which creates good contact of single-phase TiC>2 and Halloysite. 10 mL water was added to the powder mixer and probe sonicated for 10 min at 80% intensity (output energy -6000J) to disperse the TiC>2- Halloysite mixture in water. The dispersion was transferred to a 250 mL beaker and additional 40 mL water was added. After 30 min vigorous stirring, 2.65 wt% Pt ions were added to the solution. The stirring was continued for another 60 min to impregnate the Pt on TiO2-Halloysite. The surface Pt-ions were reduced using a NaBH4 and NaOH mixture solution. After 30 min, the solid Pt-Na, B/(TiO2+Halloysite) were separated using centrifugation and washed with water to remove the unreacted Pt ions and NaBH4. The inorganic powder sample was dried at 105 -C for 2 h.

Example 1(e). Synthesis of 2.65%Pt-Na, B/(70%TIO2 + 30%Halloysite): 1.4 g of single-phase TiC>2 (anatase) were mixed with 0.6 g of Halloysite clay materials. The mixture was prepared by an acoustic sonication mixer, which creates good contact of single-phase TiC>2 and Halloysite. 10 mL water was added to the powder mixer and probe sonicated for 10 min at 80% intensity (output energy -6000J) to disperse the TiC>2- Halloysite mixture in water. The dispersion was transferred to a 250 mL beaker and additional 40 mL water was added. After 30 min vigorous stirring, 2.65 wt% Pt ions were added to the solution. The stirring was continued for another 60 min to impregnate the Pt on TiO2-Halloysite. The surface Pt-ions were reduced using a NaBH4 and NaOH mixture solution. After 30 min, the solid Pt-Na, B/(TiO2+Halloysite) were separated using centrifugation and washed with water to remove the unreacted Pt ions and NaBH4. The inorganic powder sample was dried at 105 -C for 2 h.

Example 1(f). Synthesis of 2.65%Pt-Na, B/(TIO2:ZrO2 + Halloysite): 1.6 g of single-phase TiO2 (anatase) and ZrO2 were mixed at 9:1 vol% with 0.4g of Halloysite clay materials. The mixture was prepared by an acoustic sonication mixer, which creates good contact of single-phase TiO2:ZrO2 and Halloysite. 10 mL water was added to the powder mixer and probe sonicated for 10 min at 80% intensity (output energy -6000J) to disperse the TiO2:ZrO2-Halloysite in water. The dispersion was transferred to a 250 mL beaker and additional 40 mL water was added. After 30 min vigorous stirring, 2.65 wt% Pt ions were added to the solution. The stirring was continued for another 60 min to impregnate the Pt on TiO2:ZrO2-Halloysite. The surface Pt-ions were reduced using a NaBH4 and NaOH mixture solution. After 30 min, the solid Pt-Na, B/(TiO2:ZrO2+Halloysite) were separated using centrifugation and washed with water to remove the unreacted Pt ions and NaBH4. The inorganic powder sample was dried at 105 -C for 2 h.

Example 1(g). Synthesis of 2.65%Pt-Na, B/(Fe(OH)3 + Halloysite): 1.6 g of Fe(OH)s were mixed with 0.4 g of Halloysite clay materials. The mixture was prepared by acoustic sonication mixer, which create good contact of Fe(OH)s and Halloysite. 10 mL water was added to the powder mixer and probe sonicated for 10 min at 80% intensity (output energy -6000J) to disperse the Fe(OH)3-Halloysite in water. The dispersion was transferred to 250 mL beaker and additional 40 mL water were added. After 30 min vigorous stirring, 2.65 wt% Pt ions were added to the solution. The stirring was continued for another 60 min to impregnate the Pt on Fe(OH)3-Halloysite. The surface Pt-ions were reduced using a NaBH4 and NaOH mixture solution. After 30 min, the solid Pt-Na, B/(Fe(OH)3+Halloysite) were separated using centrifugation and washed with water to remove the unreacted Pt ions and NaBH4. The inorganic powder sample were dried at 105 °-C for 2 h.

Example 1(h). Synthesis of 2.65%Pt-Na, B/(TIO2:Fe(OH)3 + Halloysite): 1.6 g of single-phase TiO2 (anatase) and Fe(OH)s were mixed at 1 :1 vol% with 0.4 g of Halloysite clay materials. The mixture was prepared by an acoustic sonication mixer, which creates good contact of single-phase TiO2: Fe(OH)s and Halloysite. 10 mL water was added to the powder mixer and probe sonicated for 10 min at 80% intensity (output energy -6000J) to disperse the TiC : Fe(OH)3-Halloysite in water. The dispersion was transferred to a 250 mL beaker and additional 40 mL water was added. After 30 min vigorous stirring, 2.65 wt% Pt ions were added to the solution. The stirring was continued for another 60 min to impregnate the Pt on TiO2:Fe(OH)3-Halloysite. The surface Pt-ions were reduced using a NaBH4 and NaOH mixture solution. After 30 min, the solid Pt-Na, B/(TiO2:Fe(OH)3+Halloysite) were separated using centrifugation and washed with water to remove the unreacted Pt ions and NaBH4. The inorganic powder sample was dried at 105 °-C for 2 h. Example 1 (i). Synthesis of 2.65%Pt-Na, B/Fe(0H)3: 2.0 g of amorphous Fe(OH)s (5 nm) were dispersed in 10 mL water and probe sonicated for 10 min at 80% intensity (output energy -6000J) to disperse the amorphous Fe(OH)s in water. The dispersion was transferred to a 250 mL beaker and additional 40 mL water was added. After 30 min vigorous stirring, 2.65 wt% Pt ions were added to the solution. The stirring was continued for another 60 min to impregnate the Pt on amorphous Fe(OH)s surface. The surface Ptions were reduced using NaBFL and NaOH mixture solution. After 30 min, the solid Pt- Na, B/Fe(OH)s were separated using centrifugation and washed with water to remove the unreacted Pt ions and NaBFU. The inorganic powder sample was dried at 105 -C for 2 h.

Example 2(a). Synthesis of 2.65%Pt-Na, B/(TIO2+Halloysite) and 2.65%Pt-Na, B/Fe(OH)3 (1 :1 ratio) physical mixture: About 0.1 g 2.65% Pt-Na, B/(TiO2+ Halloysite) prepared as described in Example-1 (c) above and 0.1 g 2.65% Pt- Na, B/Fe(OH)s prepared as described in Example-1 (g) were mixed for 2 min using acoustic mixing method (Resodyn). The mixed powder was sonicated in 6 g water using probe sonication for 30 min (Fisherbrand). Then, the suspended powder was coated on the inside surface of a 1 cm*1cm filter substrate for 4 - 6 times until the total amount of coated sample is 5.6 mg. The coated filter was dried at 150 -C after each coating for I Q- 20 minutes.

Example 2(b). Synthesis of 2.65%Pt-Na, B/(TIO2+Halloysite) and 2.65%Pt-Na, B/Fe(OH)3 (1 :9 ratio) physical mixture: About 0.02 g 2.65% Pt-Na, B/(TiO2+ Halloysite) prepared as described in Example-1 (c) above and 0.18 g 2.65% Pt- Na, B/Fe(OH)s prepared as described in Example-1 (g) were mixed (1 :9 ratio) for 2 min using acoustic mixing method (Resodyn). The mixed powder was sonicated in 6 g water using probe sonication for 30 min (Fisherbrand). Then, the suspended powder was coated on the inside surface of a 1 cm*1cm filter substrate for 4 - 6 times until the total amount of coated sample is 5.6 mg. The coated filter was dried at 150 -C after each coating for 10-20 minutes.

Example 2(c). Synthesis of 2.65%Pt-Na, B/(TIO2+Halloysite) and 2.65%Pt-Na, B/Fe(OH)3 (9:1 ratio) physical mixture: About 0.1 g 2.65% Pt-Na, B/(TiO2+ Halloysite) prepared as described in Example-1 (c) above and 0.1 g 2.65% Pt- Na, B/Fe(OH)s prepared as described in Example-1 (g) were mixed (9:1 ratio) for 2 min using acoustic mixing method (Resodyn). The mixed powder was sonicated in 6 g water using probe sonication for 30 min (Fisherbrand). Then, the suspended powder was coated on the inside surface of a 1 cm*1cm filter substrate for 4 - 6 times until the total amount of coated sample is 5.6 mg. The coated filter was dried at 150 -C after each coating for 10-20 minutes.

Example 3: Experimental set-up for chamber evaluation: For chamber evaluation, 150 mg of the synthesized powder samples were dispersed in 6 mL water and probe sonicated for 30 min at 80% intensity (output energy ~16000J). The dispersion was used to dip coat a 1cm*1cm honeycomb ceramic substrate for 4-6 times until ~5.6 mg powder was coated on the substrate to create the filter. The coated filter was dried at 150 -C after each coating for 10-20 minutes. The filter was inserted into a 3D printed sample holder. The sample holder was placed in a stainless-steel continuous flow reactor, connected with an inlet gas mixture tube in one side and a gas chromatography system in another side. The inlet gas mixture contained humidified air and 1 :32 ppm HCHO:Methanol gas mixture. The higher performing catalyst materials in the chamber evaluation set up were tested in a hospital ductless fume hood application architecture set up, which is termed unit evaluation method.

Example 4: Experimental set-up for unit evaluation: For unit-evaluation systems, the system contained four-stages. Each stage can hold four 5cm*5cm filters with catalyst powder. To coat substrates with catalytic materials, a 10% dispersion of the catalytic material was dispersed in water and sonicated for 30 min. Each of the substrates were dip coated 4 times to load catalyst in an amount of about 1g of the materials on the substrate surface to create the filter. The filter was dried at 150 °C for 30 min. The dried filter containing catalyst material was inserted into the unit evaluation system in the following architecture. The inlet gas mixture contained humidified air and 5:10 ppm HCHO:Methanol gas mixture. The concentration of VOC was measured after every stage of the unit evaluation system. The schematic diagram is presented below:

Table 1 below summarizes the results using the formulae used to determine the removal of formaldehyde in the ppm level (% Performance) and formation of CO2 ppm in presence of methanol (% Deactivation).

Table 1 : Evaluation Results

Claims

1 . A catalytic material for decomposing a volatile organic compound comprising: an active catalyst comprising: a noble metal and a single-phase metal oxide, a single-phase metal hydroxide, or a combination thereof; and a supporting material comprising a first catalytic action site and a second catalytic action site, wherein the active catalyst is disposed upon both the first catalytic action site and the second catalytic action site; wherein the catalytic material decomposes the volatile organic compound in the presence or absence of visible light or ultraviolet light.

2. The catalytic material of claim 1 , wherein the single-phase metal oxide is a binary metal oxide.

3. The catalytic material of claim 1 or 2, wherein the single-phase metal oxide comprises Ti, Fe, Zr, Sn, Ce, or a combination thereof.

4. The catalytic material of claim 1 , 2, or 3, wherein the single-phase metal oxide comprises TiC>2, wherein TiC>2 is about 90% anatase phase to about 100% anatase phase.

5. The catalytic material of claim 1 , 2, 3, or 4, wherein the single-phase metal hydroxide is Fe(OH)s.

6. The catalytic material of claim 1 , 2, 3, 4, or 5, wherein the noble metal comprises Pt, Ag, Pd, Ru, Ir, or a combination thereof.

7. The catalytic material of claim 6, wherein the noble metal comprises Pt.

8. The catalytic material of claim 1 , 2, 3, 4, 5, 6, or 7, wherein the noble metal is about 0.1 wt% to about 10 wt% of the active catalyst.

9. The catalytic material of claim 1 , wherein the active catalyst comprises at least one pendant hydroxyl functional group.

10. The catalytic material of claim 1 , wherein the supporting material comprises a halloysite nanotube.

1 1 . The catalytic material of claim 10, wherein the halloysite nanotube has an inside wall and an outside wall, wherein the first catalytic action site is located on the inside wall of the halloysite nanotube, and the second catalytic action site is located on the outside wall of the halloysite nanotube.

12. The catalytic material of claim 11 , wherein the halloysite nanotube comprises at least a first hydroxyl functional group at the first catalytic action site and at least a second hydroxyl functional group at the second catalytic action site of the supporting material.

13. The catalytic material of claim 1 , wherein the weight ratio of the active catalyst to the supporting material is about 7:3 to about 19:1 .

14. The catalytic material of claim 1 , wherein the size of the active catalyst is less than 20 nm in diameter.

15. The catalytic material of claim 1 , wherein the size of the catalytic material is less than 20 nm in diameter.

16. The catalytic material of claim 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, or 15, further comprising a honeycomb ceramic substrate.

17. The catalytic material of claim 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, or 16, wherein the catalytic material decomposes about 75% of the volatile organic compound in the presence or absence of visible light or ultraviolet light, in less than about 30 seconds.

18. The catalytic material of claim 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, or

17, wherein the volatile organic compound is formaldehyde.

19. The catalytic material of claim 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17, or 18, wherein the catalytic material does not lose more than 5% of initial performance after at least 72 hours in an environment with a concentration of the volatile organic compound greater than 5 ppm.

20. A filter comprising: a honeycomb ceramic substrate; and the catalytic material of claim 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17,

18, or 19 coated on the honeycomb ceramic substrate to form the filter; wherein the filter decomposes a volatile organic compound from an environment in the presence or absence of visible light or ultraviolet light.