# US 11,305,344 B2 · Process for the preparation of bimetallic core/shell nanoparticles and their catalytic applications

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- Number: US 11,305,344 B2
- Document ID: US11305344B2
- Status: Granted
- Kind: B2
- Application number: 16/345,335
- Filed: 2017-10-25
- Published: 2019-08-15
- Granted: 2022-04-19
- Earliest claimed: 2016-10-26
- Assignees: Council of Scientific and Industrial Research
- Applicants: Council of Scientific and Industrial Research
- Inventors: Vinod Chathakudath Prabhakaran; Vysakh Alengattil Bharathan
- Web page: https://patentgrep.com/patent/US11305344B2

## CPC

- B22F 9/24: starting from liquid metal compounds, e.g. solutions
- B01J 23/52: Gold
- B01J 23/89: combined with noble metals
- B01J 23/8906: {Iron and noble metals}
- B01J 23/8913: {Cobalt and noble metals}
- B01J 23/892: {Nickel and noble metals}
- B01J 23/8926: {Copper and noble metals}
- B01J 35/393: {Metal or metal oxide crystallite size}
- B01J 35/395: {Thickness of the active catalytic layer}
- B01J 35/397: {Egg shell like}
- B01J 35/45: Nanoparticles
- B01J 37/0072: {Preparation of particles, e.g. dispersion of droplets in an oil bath}
- B01J 37/0234: {Impregnation and coating simultaneously}
- B01J 37/16: Reducing
- B22F 1/17: Metallic particles coated with metal
- C22C 5/02: Alloys based on gold
- B01J 35/23: in a colloidal state
- B01J 2235/00: Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
- B01J 2235/15: X-ray diffraction
- B01J 2235/30: Scanning electron microscopy; Transmission electron microscopy
- B22F 2301/10: Copper
- B22F 2301/15: Nickel or cobalt
- B22F 2301/255: Silver or gold
- B22F 2301/35: Iron
- B22F 2999/00: Aspects linked to processes or compositions used in powder metallurgy
- C07C 5/02: by hydrogenation (simultaneous hydrogenation and dehydrogenation C07C5/52)
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

The present invention disclosed an improved process for the preparation of bimetallic core-shell nanoparticles by using facile aqueous phase synthesis strategy and their application in catalysis such as selective hydrogenation of alkynes into alkenes or alkanes and CO hydrogenation to hydrocarbons.

## Claims

### Claim 1

An improved process for the preparation of bimetallic core-shell nanoparticles, the process comprising the steps of:
a) adding a solution of reducing agent in water to an aqueous solution of gold precursor with constant stirring to afford gold nanoparticles followed by stirring for 10 to 15 minutes;
b) adding a transition metal precursor to the solution of step (a) followed by adding a capping agent, wherein the capping agent is selected from the group consisting of cetyltrimethylammoniumbromide (CTAB), cetyltrimethylammonium chloride (CTAC), Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG), poly vinyl pyrollidone (PVP) and trisodiumcitrate and heating at a temperature in the range of 60 to 70° C.; and
c) adding a mixture of hydrazine hydrate and sodium hydroxide to the solution of step (b) to afford the bimetallic core-shell nanoparticles, wherein a core of the core-shell nanoparticles is made up of the gold,
a shell of the core-shell nanoparticles is made up of the transition metal, and
said process is carried out in an aqueous medium.

### Claim 2 (depends on 1)

The process as claimed in claim 1, wherein said reducing agent is selected from the group consisting of sodium borohydride, ascorbic acid, tri sodium citrate and hydrazine.

### Claim 3 (depends on 1)

The process as claimed in claim 1, wherein said transition metal precursor is selected from the group consisting of nickel, cobalt, copper and iron.

### Claim 4 (depends on 1)

The process as claimed in claim 1, wherein said bimetallic core-shell nanoparticles are used for selective hydrogenation of alkynes into alkenes or alkanes.

### Claim 5 (depends on 1)

The process as claimed in claim 1, wherein said bimetallic core-shell nanoparticles are used for various catalytic conversions selected from organic transformations including NO2 reduction, transfer hydrogenation of various functional groups including carbonyl, nitro, alkenes, steam reforming, CO2 and CO hydrogenation reactions, methane reforming, and hydrogen production from hydrazine, ammonia borane, and sodium borohydride.