# US 11,305,262 B2 · Photocatalyst nanocomposite

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- Number: US 11,305,262 B2
- Document ID: US11305262B2
- Status: Granted
- Kind: B2
- Application number: 16/437,614
- Filed: 2019-06-11
- Published: 2020-12-17
- Granted: 2022-04-19
- Earliest claimed: 2019-06-11
- Assignees: Imam Abdulrahman Bin Faisal University
- Applicants: Imam Abdulrahman Bin Faisal University
- Inventors: Nuhad Abdullah Alomair; Hanan Hussein Amin Mohamed
- Web page: https://patentgrep.com/patent/US11305262B2

## CPC

- B01J 23/8953: {with zinc, cadmium or mercury}
- B01J 21/18: Carbon
- B01J 23/38: of noble metals
- B01J 23/60: with zinc, cadmium or mercury
- B01J 35/39: Photocatalytic properties
- B01J 35/45: Nanoparticles
- B01J 35/647: {2-50 nm}
- B01J 37/031: {Precipitation}
- B01J 37/038: {to form slurries or suspensions, e.g. a washcoat}
- B01J 37/08: Heat treatment {(B01J37/0009, B01J37/0018 take precedence)}
- C02F 1/30: by irradiation
- C02F 1/725: {by catalytic oxidation}
- B01J 2235/00: Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
- B01J 2235/10: Infrared [IR]
- B01J 2235/15: X-ray diffraction
- B01J 2235/30: Scanning electron microscopy; Transmission electron microscopy
- C02F 2101/308: {Dyes; Colorants; Fluorescent agents}
- C02F 2305/08: Nanoparticles or nanotubes
- C02F 2305/10: Photocatalysts
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- 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

An efficient photocatalyst nanocomposite comprising reduced graphene oxide, noble metal, and a metal oxide prepared by a one-step method that utilizes date seed extract as a reducing and nanoparticle determining size agent. The photocatalyst of the invention is a more effective sunlight photocatalyst than that prepared by traditional method in the photo decomposition of organic compounds in contaminated water.

## Claims

### Claim 1

A photocatalyst nanocomposite, comprising:
Au nanoparticles, hexagonal wurtzite ZnO nanoparticles, and reduced graphene oxide (rGO),
wherein the photocatalyst nanocomposite is made by the method of
preparing an aqueous suspension of zinc acetate, chloroauric acid, and graphene oxide;
mixing the aqueous suspension with a date seed extract to form a mixture; and
heating the mixture at a temperature in the range of 100-200° C. for a time in the range of 10 to 20 hours to form the photocatalyst nanocomposite;
wherein the date seed extract is prepared by grinding a date seed and heating the ground date seed in water at a temperature in the range of 60 to 100° C. for a time in the range of 1 to 5 hours and separating solids to form the date seed extract in the form of a liquid,
wherein the photocatalyst nanocomposite comprises rGO in an amount in the range of 40 wt. % to 60 wt. % of the total weight of the photocatalyst nanocomposite,
wherein the Au nanoparticles have a diameter in the range of 15 to 20 nm and are homogeneously distributed on the ZnO nanoparticles and on the rGO; the ZnO nanoparticles have a diameter in the range of 30 to 40 nm and are present on the rGO; and the Au nanoparticles are present in an amount in the range of 2 mol. % to 10 mol. % based on the molar amount of the ZnO nanoparticles, and
wherein the photocatalyst nanocomposite catalyzes the photodecomposition of methyl orange in an aqueous solution at a faster rate than a photocatalyst nanocomposite prepared by a substantially similar method but with NaOH instead of a date seed extract.

### Claim 2 (depends on 1)

The photocatalyst nanocomposite of claim 1, wherein the photocatalyst composite comprises rGO in an amount in the range of 48 wt. % to 52 wt. % of the total weight of the nanocomposite.

### Claim 3 (depends on 1)

The photocatalyst nanocomposite of claim 1, wherein the photocatalyst nanocomposite comprises 5 mol. % of Au based on the molar amount of the ZnO.

### Claim 4 (depends on 1)

The photocatalyst nanocomposite of claim 1, wherein:
reduced graphene oxide is present in an amount of about 49 wt. %;
ZnO nanoparticles are present in an amount of about 45.5 wt. %, each weight percent relative to the total weight of the photocatalyst nanocomposite; and
gold nanoparticles in an amount of about 5.5 mol. % based on the molar amount of the ZnO.

### Claim 5 (depends on 1)

A method of photodecomposing of an organic compound, comprising:
contacting the photocatalyst nanocomposite of claim 1 with an aqueous solution of an organic compound to form a mixture, and
irradiating the mixture with sunlight.

### Claim 6 (depends on 4)

A process of purifying water contaminated with an organic material, comprising:
contacting the contaminated water with the photocatalyst nanocomposite of claim 4, and
irradiating the mixture with sunlight.

### Claim 7 (depends on 1)

The photocatalyst nanocomposite of claim 1, wherein the methyl orange is present in the aqueous solution at a concentration of 20 ppm, and the photocatalyst is present in the aqueous solution at a concentration of 1 g/L.

### Claim 8 (depends on 1)

The photocatalyst nanocomposite of claim 1, wherein in the preparation of the date seed extract, the ground date seed is suspended in water at a concentration in a range of 250-350 g/L.

### Claim 9 (depends on 1)

The photocatalyst nanocomposite of claim 1, wherein in the preparation of the date seed extract, the ground date seed is heated in water at a temperature in a range of 70-90° C.

### Claim 10 (depends on 1)

The photocatalyst nanocomposite of claim 1, wherein the mixture comprises 33 vol % date seed extract relative to a total volume of the mixture.

### Claim 11 (depends on 7)

The photocatalyst nanocomposite of claim 7, wherein about 99% of the methyl orange is photodegraded after 65 minutes of illumination.

### Claim 12 (depends on 7)

The photocatalyst nanocomposite of claim 7, wherein about 95% of the methyl orange is photodegraded after 65 minutes of illumination.

### Claim 13 (depends on 12)

The photocatalyst nanocomposite of claim 12, wherein the illumination source is a 125 W sunlight simulating lamp.

### Claim 14 (depends on 1)

The photocatalyst nanocomposite of claim 1, wherein the Au nanoparticles comprise Au nanoparticles that are in contact with the rGO but not in contact with the ZnO nanoparticles.

### Claim 15 (depends on 14)

The photocatalyst nanocomposite of claim 14, wherein the Au nanoparticles further comprise Au nanoparticles that are in contact with both the rGO and the ZnO nanoparticles.

### Claim 16 (depends on 1)

The photocatalyst nanocomposite of claim 1, wherein the rGO comprises at least three stacked sheets of rGO intercalated with the Au nanoparticles and the ZnO nanoparticles.