A heterogeneous mechanism for the catalytic decomposition of hydroperoxides and oxidation of alkanes over CeO2 nanoparticles: A combined theoretical and experimental study

Abstract

A nanoparticulate CeO2 catalyst is presented that is able to oxidize cyclohexane to K/Aoil (a mixture of cyclohexanone and cyclohexanol) using hydroperoxides as oxidizing species. The improvement in selectivity with decreasing particle size suggests the existence of a structure-activity relationship in this process, and points to a preferential activation of cyclohexane at defective corner or edge sites. A detailed theoretical study of the reaction mechanism over three different CeO2 catalyst models shows that cyclohexane is preferentially activated by bi coordinated oxygen atoms present at the edges of small particles, following a Mars van Krevelen mechanism which has been confirmed by in situ IR spectroscopy and 18 O/ 16 O isotopic exchange experiments. The process is fully heterogeneous, and the catalyst can be reused without loss of activity up to four cycles.

Organic Acid Anions Modified α-Co(OH)2 with Enhanced Activity for the Decomposition of Cyclohexyl Hydroperoxide

“…Recent works were devoted to exploring new catalyst for effectively decomposing CHHP in absence of alkali medium. − Cerium oxides with various shapes and particle sizes have been used as catalysts for CHHP decomposition . Mono- and dinuclear vanadium complexes have been identified as very promising homogeneous catalysts for CHHP decomposition .…”

“…13−17 Cerium oxides with various shapes and particle sizes have been used as catalysts for CHHP decomposition. 18 Mono-and dinuclear vanadium complexes have been identified as very promising homogeneous catalysts for CHHP decomposition. 19 The active sites of gold nanoparticles encapsulated in the porous organic networks of yolk−shell structure were developed and have been used as effective catalysts to decompose CHHP.…”

Semiempirical computational study of oxygen vacancies in a decahedral anatase nanoparticle

“…For reactions of selective catalytic oxidation, fine tuning of oxygen vacancies formation energy may be needed to obtain the best combination of catalytic activity and selectivity toward desired products. Such a tuning is possible using size and structure effects in nanoparticles as it was demonstrated for cyclohexane oxidation over CeO 2 nanoparticles …”

“…Such a tuning is possible using size and structure effects in nanoparticles as it was demonstrated for cyclohexane oxidation over CeO 2 nanoparticles. [17] Titanium dioxide is a very widely used adsorbent, component of solar cells, catalyst and catalyst support. Oxygen vacancies in surface and inner layers of TiO 2 were previously studied computationally and the results are summarized in Table 1.…”

Catalyst-free and solvent-free oxidation of cycloalkanes (C5-C8) with molecular oxygen: Determination of autoxidation temperature and product distribution

“…In addition, cycloalkanols and cycloalkanones are important intermediates and solvents in the chemical industry and academic research [25][26][27][28][29][30][31]. To realize this necessary transformation from cycloalkanes to their oxidized products, several oxidants can be employed, such as iodosylbenzene [32][33][34][35][36][37][38], iodosylbenzene diacetate [34,[38][39][40], tert-butyl hydroperoxide [41][42][43][44][45][46][47][48][49], m-chloroperoxybenzoic acid [50][51][52][53][54][55], hydrogen peroxide [56][57][58][59][60][61][62][63], molecular oxygen [64][65][66][67][68][69][70]…”