US 11,701,640 B2
Cobalt-based single-atom dehydrogenation catalysts having improved thermal stability and method for producing olefins from corresponding paraffins by using the same
Young Eun Cheon, Daejeon (KR); Hee Soo Kim, Daejeon (KR); Dong Min Yun, Daejeon (KR); Ho Won Lee, Daejeon (KR); and Ju Hwan Im, Daejeon (KR)
Assigned to SK Innovation Co., Ltd., Seoul (KR)
Filed by SK Innovation Co., Ltd., Seoul (KR)
Filed on Jun. 25, 2021, as Appl. No. 17/358,230.
Claims priority of application No. 10-2020-0077570 (KR), filed on Jun. 25, 2020; and application No. 10-2021-0048929 (KR), filed on Apr. 15, 2021.
Prior Publication US 2021/0402379 A1, Dec. 30, 2021
Int. Cl. B01J 23/75 (2006.01); B01J 37/08 (2006.01); B01J 21/08 (2006.01); B01J 35/00 (2006.01); B01J 35/02 (2006.01); B01J 37/02 (2006.01); C07C 5/333 (2006.01)
CPC B01J 23/75 (2013.01) [B01J 21/08 (2013.01); B01J 35/0013 (2013.01); B01J 35/0046 (2013.01); B01J 35/026 (2013.01); B01J 37/0217 (2013.01); B01J 37/0221 (2013.01); B01J 37/088 (2013.01); C07C 5/3332 (2013.01); C07C 2521/08 (2013.01); C07C 2523/75 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method for preparation of a single-atom cobalt-based catalyst, which comprises the steps of:
a) thermally treating silica as a support at a temperature ranging from 600 to 870° C. to induce shrinkage of the support, and simultaneously to remove its surface hydroxyl groups, followed by subjecting the shrunken support to a high-temperature aqueous treatment in a temperature range of 70 to 150° C. to afford a pretreated silica having hydroxyl groups selectively activated thereon;
b) preparing an aqueous dispersion of the pretreated silica;
c) preparing a pH-adjusted aqueous dispersion of the pretreated silica by adding a base to the aqueous dispersion of the pretreated silica to adjust the pH of the dispersion to at least 10;
d) separately preparing a pH-adjusted cobalt precursor aqueous solution by preparing an aqueous solution of a cobalt precursor having an oxidation number of 3+ and adding a base to the aqueous solution;
e) combining the pH-adjusted aqueous dispersion of the pretreated silica with the pH-adjusted aqueous solution of the cobalt precursor to afford an aqueous dispersion in which at least a part of the cobalt ions having an oxidation number of 3+ is adsorbed onto the surface of the pretreated silica;
f) removing cobalt ions which remain not adsorbed onto the pretreated silica; and
g) thermally treating the cobalt ion-adsorbed silica obtained in step f);
wherein cobalt having an oxidation number of 2+ exists in an isolated form of single-atom on the pretreated silica while being tetrahedrally coordinated at trihydroxyl groups present on the surface of the pretreated silica.