In:
ChemCatChem, Wiley, Vol. 13, No. 2 ( 2021-01-20), p. 610-616
Abstract:
Deep oxidation/dehydrogenation are longstanding problems for decades in catalytic oxidative dehydrogenation (ODH) of cyclohexane and other alkanes. Here we show a metal‐free catalyst of nanodiamonds (NDs) with unique sp 3 @sp 2 hybrid structure that catalyzes CO x ‐resistant cyclohexane ODH with remarkable reactivity towards cyclohexene production. The selectivity of cyclohexene can reach as high as 67 % with significantly suppressed CO x emission ( 〈 5 %), which is on top of the highest reported values among other metal(oxide)/metal‐free catalysts. Structural evolution of sp 3 @sp 2 NDs under annealing treatments and their specific surface functional groups are systematically studied using TEM, XPS, Raman and TPD. By comparing with carbon nanotubes (CNTs), we found that the carbonyl groups stabilized on strained sp 3 @sp 2 core‐shell NDs enhanced the cyclohexene selectivity via preferential cleavage of C−H over C−C bond. Kinetic studies further revealed the underlying reaction pathways that cyclohexane is rapidly dehydrogenated to cyclohexene which subsequently transforms into benzene (fast) and CO x (slow). Deep oxidation of both cyclic hydrocarbons is largely suppressed due to the low density of electrophilic functional groups on strongly curved graphitic surface of sp 3 @sp 2 NDs.
Type of Medium:
Online Resource
ISSN:
1867-3880
,
1867-3899
DOI:
10.1002/cctc.202001380
Language:
English
Publisher:
Wiley
Publication Date:
2021
detail.hit.zdb_id:
2501161-3
