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A Mesoporous Cobalt Aluminate Spinel Catalyst for Nonoxidative Propane Dehydrogenation
Author(s) -
Hu Bo,
Kim WunGwi,
Sulmonetti Taylor P.,
Sarazen Michele L.,
Tan Shuai,
So Jungseob,
Liu Yujun,
Dixit Ravindra S.,
Nair Sankar,
Jones Christopher W.
Publication year - 2017
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201700647
Subject(s) - dehydrogenation , catalysis , mesoporous material , propane , chemistry , physisorption , cobalt , inorganic chemistry , spinel , selectivity , pyridine , desorption , propene , materials science , organic chemistry , adsorption , metallurgy
A mesoporous CoAl 2 O 4 spinel (Co‐Al) is synthesized by a one‐step evaporation‐induced self‐assembly (EISA) method. N 2 physisorption and TEM are used to demonstrate the presence of mesopores within the Co‐Al material. The spinel crystal structure of Co‐Al, in which Co occupies tetrahedral (T d ) sites, is confirmed by using XRD and UV/Vis spectroscopy. In nonoxidative propane dehydrogenation at 550 °C, a propane conversion of approximately 8 % is observed for Co‐Al with a >80 % propylene selectivity, which corresponds to a turnover frequency of 5.1 h −1 based on an estimation of the number of active Co sites by using NH 3 temperature‐programmed desorption. A much higher propane conversion rate and a circa 80 % propylene selectivity is observed upon reaction at 600 °C. Continuous deactivation of the catalyst is observed for Co‐Al at this elevated temperature. In situ X‐ray absorption spectroscopy results suggest that Co remains as a T d Co 2+ species under the reaction conditions. The T d Co 2+ sites within the Co‐Al material are thus proposed to act as Lewis acidic active sites; this acidity is verified using IR spectroscopy with pyridine as a probe molecule.