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Selective Oxidation of Cyclohexane Using Graphene Oxide‐Supported Ceria Nanocomposites with Exposed Active {1 0 0} Facets
Author(s) -
Arumugam Selvamani,
Mohan Babu Cadiam,
Vasudevan Srinivasan Vinju,
Vanaraj Ramkumar,
Rukmanikrishnan Balasubramanian,
Periyasamy Thirukumaran,
Asrafali Shakila Parveen
Publication year - 2017
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201700769
Subject(s) - high resolution transmission electron microscopy , cyclohexane , graphene , x ray photoelectron spectroscopy , oxide , materials science , catalysis , adsorption , nanocrystalline material , chemical engineering , nanocomposite , nanotechnology , chemistry , organic chemistry , metallurgy , transmission electron microscopy , engineering
The present study is focused on the synthesis and characterization of ceria loaded graphene oxide (GO) and investigates their catalytic activity on vapor phase selective oxidation of cyclohexane. In this regards, we have synthesized various loading of CeO 2 on GO with two different morphology includes nanocrystals and flower‐like, which designated as CeO 2 ( x )/GO (where x= 0, 0.2, 0.4, 0.6, 0.8 and 1.0 wt.% ). The physico‐chemical properties of the materials were extensively studied with help of XRD, N 2 adsorption desorption (BET), DRUV‐Vis, HRSEM, HRTEM, H 2 ‐TPR and XPS techniques. The crystalline nature of materials were analyzed by XRD, pure ceria shows high crystalline size about 15. 3 nm compared to others. Surface area of synthesized materials has been obtained with help of N 2 adsorption desorption analysis, pure ceria and graphene oxide shows surface area about 93 and 574 m 2 /g, respectively. XPS and DRUV‐Vis spectra were confirms the presence of enormous Ce 3+ ions in the lattice. The presence of nanocrystals and flower‐like morphology of CeO 2 ( x )/GO were confirmed by HRSEM images. HRTEM images were clearly illustrated that the presence of dominant active {1 0 0} facets in flower‐like CeO 2 /GO than that of nanocrystalline morphology. The catalytic activity of materials has been evaluated on selective oxidation of cyclohexane using air as a green oxidant. The key reaction parameters were varied to study the stability, activity and selectivity of the catalysts. The activity of the catalysts is correlated with their physico‐chemical properties, and these results concluded that suitable amount of ceria and it's flower‐like morphology on GO is essential for selective oxidation of cyclohexane at low temperature (180 °C) compared to nanocrystalline morphology. Hence, flower‐like CeO 2 (0.4)/GO is a most suitable catalyst for high conversion (90%) of cyclohexane into cyclohexanone with 74% selectivity due to occurrence of enormous {1 0 0} facet and Ce 3+ .