Core-shell particles with catalytic activity

Patent metadata

Field	Value
Publication number	US-2016354762-A1
Application number	US-201615237233-A
Country	US
Kind code	A1
Filing date	Aug 15, 2016
Priority date	May 30, 2011
Publication date	Dec 8, 2016
Grant date	—

Abstract

The present invention pertains to novel core-shell particles comprising a core of iron oxide and a shell of cobalt oxide, characterized in that they are spherical with a number average diameter, as measured by TEM, of between 1 and 20 nm. This invention is also directed to their uses in the manufacture of a catalyst, and to the method for preparing these particles, by precipitating cobalt oxide onto magnetite or hematite particles which are themselves precipitated from Fe(III) and optionally Fe(II) salts.

First claim

1 .- 11 . (canceled)

12 . Core-shell particles obtained according to a method comprising:
(a) preparing an aqueous solution comprising a ferric salt, at a temperature of less than 50° C.; (b) adding at least one base to said aqueous solution, so as to obtain a suspension of iron oxide particles having a pH value of from 10 to 14; (c) washing the suspension; (d) adding a strong acid to the washed suspension to peptize the washed suspension; (e) reacting at least one base with said peptized suspension, until the pH reaches a value from 10 to 14, at a temperature of from 50 to 95° C.; (f) adding a cobalt salt to the heated suspension in order to obtain spherical particles having a core of iron oxide and a shell comprising cobalt oxide, wherein the spherical particles comprise a core of iron oxide and a shell of cobalt oxide, characterized in that the core-shell particles are spherical with a number average diameter, as measured by TEM, of between 1 and 20 nm.

13 . The core shell particles according to claim 12 , characterized in that the aqueous solution comprising the ferric salt further includes a ferrous salt in a molar ratio of Fe(III) to Fe(II) of 2:1, whereby the iron oxide particles are magnetite particles.

14 . The core shell particles according to claim 12 , characterized in that the ferric salt is ferric nitrate, ferric chloride or ferric hydroxide.

15 . The core shell particles according to claim 13 , characterized in that the ferrous salt is ferrous nitrate, ferrous chloride or ferrous hydroxide.

16 . The core shell particles according to claim 12 characterized in that the cobalt salt is cobalt nitrate, cobalt chloride or cobalt sulphate.

17 . The core shell particles according to claim 12 , characterized in that the strong acid is nitric acid or hydrochloric acid.

18 . Core-shell particles comprising a core of iron oxide and a shell of cobalt oxide, characterized in that the core-shell particles are spherical with a number average diameter, as measured by TEM, of between 1 and 20 nm.

19 . Core-shell particles according to claim 18 , characterized in that the core comprises magnetite or hematite and the shell comprises cobalt oxide.

Assignees

• Total Raffinage Chimie

Inventors

• Calderone Vincenzo Roberto
• Shiju Nirappurackal Raveendran
• Rothenberg Gad
• Curulla-Ferre Daniel

Classifications

• B01J2235/00

  Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties · CPC title

• B01J35/53

  with a core-shell structure · CPC title

• B01J35/45

  Nanoparticles · CPC title

• B01J23/75 Primary

  Cobalt · CPC title

• B01J37/0217

  Pretreatment of the substrate before coating · CPC title