# US 2013/0153483 A1 · Photocatalytic composite material

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- Number: US 2013/0153483 A1
- Document ID: US20130153483A1
- Status: Published application
- Kind: A1
- Application number: 13/328,360
- Filed: 2011-12-16
- Published: 2013-06-20
- Earliest claimed: 2011-12-16
- Inventors: Franca MORAZZONI; Roberto Scotti; Maurizio Crippa; Massimiliano D'Arienzo
- Web page: https://patentgrep.com/patent/US20130153483A1

## CPC

- B01J 19/123: {Ultraviolet light}
- B01D 53/88: Handling or mounting catalysts
- B01J 21/063: {Titanium; Oxides or hydroxides thereof}
- B01J 21/08: Silica
- B01J 35/39: Photocatalytic properties
- B01J 35/45: Nanoparticles
- B01J 35/647: {2-50 nm}
- B01J 35/653: {500-1000 nm}
- B01J 35/657: {larger than 1000 nm}
- B01J 35/70: characterised by their crystalline properties, e.g. semi-crystalline (catalysts comprising carbon B01J21/18; molecular sieves B01J29/00)
- B01J 35/77: Compounds characterised by their crystallite size
- B01J 37/0209: {involving a reaction between the support and a fluid}
- B01J 37/033: {Using Hydrolysis}
- B01J 37/06: Washing {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/08: Heat treatment {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/086: {Decomposition of an organometallic compound, a metal complex or a metal salt of a carboxylic acid}
- B01J 37/343: {of ultrasonic wave energy}
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- C02F 1/32: with ultraviolet light
- C02F 1/725: {by catalytic oxidation}
- B01D 2255/20707: Titanium
- B01D 2255/802: Photocatalytic
- B01J 35/695: {polymodal}
- B01J 2235/15: X-ray diffraction
- B01J 2235/30: Scanning electron microscopy; Transmission electron microscopy
- C02F 2101/345: {Phenols}
- C02F 2303/04: Disinfection
- C02F 2305/08: Nanoparticles or nanotubes
- C02F 2305/10: Photocatalysts
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)

## Abstract

Photocatalytic composite materials, namely materials capable of promoting photo-initiated chemical reactions and processes for producing such materials, are provided. The invention further provides processes for producing photocatalytic composite materials which includes a macroporous matrix, the macroporous matrix having a surface grafting of preformed titanium dioxide nanocrystals, wherein the macroporous matrix may be produced by a sol-gel technique from a precursor of the macroporous matrix in the presence of a template-forming polymer and of hydrophobically-functionalized nano-crystalline titanium-dioxide particles.

## Claims

### Claim 1

A method for producing a photocatalytic composite material comprising,
providing nano-crystalline titanium dioxide particles,
functionalizing the nano-crystalline titanium dioxide particles in a solution comprising organic molecules, the organic molecules comprising hydrophobic chains,
providing a solution comprising a template-forming polymer, and
adding to the solution comprising the template-forming polymer the functionalized titanium dioxide particles and a precursor of a porous matrix.

### Claim 2 (depends on 1)

The method of claim 1, wherein the precursor of the porous matrix is a precursor of an inorganic oxide which is transparent to UV radiation and which has a band-gap higher than the band-gap of titanium dioxide.

### Claim 3 (depends on 2)

The method of claim 2, wherein the inorganic oxide is selected from the group consisting of: silica, alumina and zirconia.

### Claim 4 (depends on 1)

The method of claim 1, wherein the precursor of the porous matrix is selected from the group consisting of: tetra-alkoxydes of silicon, tetra-alkoxydes of alluminium, tetra-alkoxydes of zirconium, alkaline metals silicates, alkaline metals aluminates and alkaline metals zirconates.

### Claim 5 (depends on 1)

The method of claim 1, wherein the precursor of the porous matrix is selected from the group consisting of tetra-methoxysilane (TMOS), tetra-ethoxysilane (TEOS) and sodium silicate Na2SiO3.

### Claim 6 (depends on 1)

The method of claim 1, wherein the template-forming polymer is selected from the group consisting of: polyethyleneglycol with a number of monomeric units higher than 100, a polypropyleneglycol and block-copolymers polyethyleneglycol/polypropyleneglycol.

### Claim 7 (depends on 1)

The method of claim 1, wherein the titanium dioxide particles comprise its anatase form.

### Claim 8 (depends on 1)

The method of claim 1, wherein the titanium dioxide particles are functionalized with an organic molecule selected from the group consisting of: primary alkylamines, primary alkoxyalkylamines, aliphatic-chain carboxylic acids, alkoxyaliphatic-chain carboxylic acids, aliphatic-chain phosphonates and alkoxyaliphatic-chain phosphonates.

### Claim 9 (depends on 8)

The method of claim 8, wherein the organic molecule is selected from the group consisting of hexylamine and 2-methoxyethylamine.

### Claim 10

A method for producing a photocatalytic composite material, comprising the following steps:
1) providing nanocrystalline titanium dioxide particles;
2) functionalizing the nanocrystalline titanium dioxide particles of step 1) in solution with an organic molecule conferring hydrophobic properties to the titanium dioxide surface and isolating hydrophobically-functionalized titanium dioxide particles;
3) providing an acidic solution containing a template-forming polymer;
4) adding to the acidic solution of the template-forming polymer of step 3) the hydrophobically-functionalized nanocrystalline titanium dioxide particles obtained at step 2) and a precursor of the porous matrix;
5) forming from the solution of step 4) a composite material intermediate;
6) treating the composite material intermediate of step 5) at a temperature between about room temperature and about 100° C. for a period of time sufficient to form a gel;
7) drying the gel obtained at step 6);
8) annealing the dried gel obtained at step 7) to provide the final photocatalytic composite material.

### Claim 11 (depends on 10)

The method of claim 10, wherein the nanocrystalline titanium dioxide particles solution of step 2) is an alcohol solution.

### Claim 12 (depends on 10)

The method of claim 10, wherein the acidic solution of step 3) is an acidic solution of a carboxylic acid.

### Claim 13 (depends on 12)

The method of claim 12, wherein the carboxylic acid is selected from the group consisting of: acetic acid and propionic acid.

### Claim 14 (depends on 10)

The method of claim 10, wherein the acidic solution of step 3) is an acidic solution of an inorganic acid.

### Claim 15 (depends on 14)

The method of claim 14, wherein the inorganic acid is selected from the group consisting of hydrochloric acid, nitric acid and sulphuric acid.

### Claim 16 (depends on 10)

The method of claim 10, wherein the formation of the composite material intermediate of step 5) comprises the step 5) moulding in a suitable mould or coating a surface of a preformed article.

### Claim 17 (depends on 10)

The method of claim 10, wherein the gel-forming step 6) is performed at a temperature up to about 80° C. and for a time ranging from about 24 to about 48 h.

### Claim 18 (depends on 10)

The method of claim 10, wherein the drying step 7) is performed at a temperature ranging from about 120° C. to about 150° C.

### Claim 19 (depends on 18)

The method of claim 18, wherein the drying step 7) is performed for a time ranging from about 24 to about 48 h.

### Claim 20 (depends on 10)

The method of claim 10, wherein the annealing step 8) is performed at a temperature ranging from about 500° C. to about 900° C.

### Claim 21 (depends on 20)

The method of claim 20, wherein the annealing step 8) is performed for a time ranging from about 3 to about 10 hours.

### Claim 22 (depends on 10)

The method of claim 10, wherein step 3) comprises adding a carboxylic acid to acidify the solution in a concentration from about 0.05 M to about 0.60 M.

### Claim 23 (depends on 22)

The method of claim 22, wherein the carboxylic acid concentration is from about 0.10 M to about 0.50 M.

### Claim 24 (depends on 22)

The method of claim 22, wherein the carboxylic acid is selected from the group consisting of: acetic acid and propionic acid.

### Claim 25 (depends on 10)

The method of claim 10, wherein step 3) comprises adding an inorganic acid to acidify the solution in a concentration from about 1.0×10−3 M and to about 4.0×10−3 M.

### Claim 26 (depends on 25)

The method of claim 25, wherein the inorganic acid is in a concentration from about 1.3×10−3 M to about 3.3×10−3 M.

### Claim 27 (depends on 25)

The method of claim 25, wherein the inorganic acid is selected from the group consisting of: hydrochloric acid, nitric acid and sulphuric acid.

### Claim 28

A photocatalytic composite material comprising a porous matrix, the porous matrix having a surface grafting of preformed titanium dioxide nanocrystals, wherein the porous matrix is an inorganic oxide which is transparent to UV radiation and which has a band-gap higher than the band-gap of titanium dioxide.

### Claim 29 (depends on 28)

The photocatalytic composite material of claim 28, wherein the inorganic oxide is selected from silica, alumina and zirconia.

### Claim 30 (depends on 28)

The photocatalytic composite material of claim 28, wherein the titanium dioxide is in its anatase form.

### Claim 31 (depends on 28)

The photocatalytic composite material of claim 28, wherein the porous matrix is macroporous and wherein the porosity percentage of the macroporous matrix is more than about 70% of the total volume, and wherein at least about 60% of the macropores have an average radius of between about 0.5 and about 2.5 μm.

### Claim 32 (depends on 31)

The photocatalytic composite material of claim 31, wherein at least about 60% of the macropores have an average radius of between about 0.5 and about 1.5 μm.

### Claim 33 (depends on 31)

The photocatalytic composite material of claim 31, wherein at least about 60% of the macropores have an average radius of between about 0.8 and about 1.2 μm.

### Claim 34 (depends on 28)

The photocatalytic composite material of claim 28, wherein the porous matrix may be microporous and/or mesoporous, wherein the porosity percentage of the matrix is more than about 70% of the total volume, and wherein at least about 60% of pores have an average radius of between about 0.0015 and about 0.015 μm.

### Claim 35 (depends on 34)

The photocatalytic composite material of claim 34, wherein at least about 60% of the pores have an average radius of between about 0.002 and about 0.010 μm.

### Claim 36 (depends on 28)

The photocatalytic composite material of claim 28, wherein the titanium dioxide is mesoporous, with an average diameter of the pores of between about 3.0 and 4.5 nm.

### Claim 37 (depends on 36)

The photocatalytic composite material of claim 36, wherein the titanium dioxide has an average diameter of the pores of about 3.6 nm.

### Claim 38 (depends on 28)

The photocatalytic composite material of claim 28, wherein the porous matrix comprises particles having an average size of between about 2 and about 3 μm.

### Claim 39 (depends on 28)

A photoreactor comprising the photocatalytic composite material of claim 28, said photoreactor adapted for allowing fluid to pass through the composite material under UV irradiation wherein said fluid is thereby purified.

### Claim 40 (depends on 39)

The photoreactor of claim 39, wherein the photocatalytic composite material comprises pellets.