Hits:

Indexed by:期刊论文

Date of Publication:2017-09-01

Journal:ACS SUSTAINABLE CHEMISTRY & ENGINEERING

Included Journals:Scopus、SCIE、EI

Volume:5

Issue:9

Page Number:7824-7831

ISSN No.:2168-0485

Key Words:CO2 methanation; Low-temperature; ZIF-67; CTAB; Cobalt

Abstract:A Co-based zeolitic imidazolate framework, ZIF-67, has been utilized as a precursor to obtain Co-based porous carbon catalysts. The obtained catalysts display an outstanding catalytic performance toward the CO2 methanation at low temperature. The ZIF-67 crystal morphology can be controlled from cubic to rhombic dodecahedron, and the original particle sizes can be regulated from 150 nm to 1 mu m in aqueous solution by cetyltrimethylammonium bromide (CTAB) surfactants. After carbonation in N-2 flow, Co-based porous carbon catalysts kept the original ZIF-67 crystal morphology and particle size but differed in the micropore property; the 0.01 wt % CTAB content led to the maximum micropore volume 0.125 cm(3)/g. The Co nanoparticles inside the carbon matrix range between 7 and 20 nm, and they are separated by the graphite-like carbon avoiding the metal sintering effectively. Furthermore, the catalysts with 0.01% CTAB addition exhibited the highest CO2 conversion (52.5%) and CH4 selectivity (99.2%) under the 72000 mL g(-1) h(-1) GHSV (gas hourly space velocity) at 270 degrees C. Noticeably, the Co/PC catalysts performed higher activity and stability than the supported catalysts 20Co/AC. The versatile way offers good prospects for low temperature CO2 methanation and prevents metal sintering effectively.