Fabrication of Bimetal CuFe2O4 Oxide Redox-Active Nanocatalyst for Oxidation of Pinene to Renewable Aroma Oxygenates

Abstract

This study report on the synthesis of spinel CuFe2O4 nanostructures by surfactant-assisted method. The catalysts were characterized by X-ray diffraction (XRD), laser Raman, transition electron microscope (TEM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), hydrogen temperature programmed reduction (H2-TPR), and Brunauer-Teller-Emmett-Teller (BET) surface area techniques. CuFe2O4 was active for pinene oxidation using tertiary butyl hydroperoxide (TBHP) to pinene oxide, verbenol, and verbenone aroma oxygenates. Under optimized reaction conditions, the spinel CuFe2O4 catalyst could afford 80% pinene conversion at a combined verbenol/verbenone selectivity of 76% within the reaction time of 20 h. The changes in catalyst synthesis solvent composition ratios induced significantly varying redox, phases, and textural structure features, which resulted in various catalytic enhancement effect. Characterization results showed the spinel CuFe2O4 catalyst possessing less than 5 wt% impurity phases, Cu(OH)2, and CuO to afford the best catalytic performance. The CuFe2O4 catalyst was recyclable to up to five reaction cycles without loss of its activity. The recyclability of the bimetal CuFe2O4 oxide catalyst was simply rendered by use of an external magnet to separate it from the liquid solution.

Morphology Modulated Photocatalytic Activity of CeO2 Nanostructures for Selective Oxidation of Biobased Alpha‐Pinene to Oxygenates

“…where E CB and E VB are the CB and VB potentials, respectively; E C is the energy of free electrons vs hydrogen electrode (4.5 eV); E g is the band gap of a semiconductor; χ is the Mulliken electronegativity of semiconductor; while (a) and (b) are the number of atoms in the compound. The absolute electronegativity of CeO 2 was estimated to be 5.59 eV, which is in agreement with the values obtained in literature (5.56 eV) [42] . Moreover, the estimated CB and VB position were respectively found to be −0.98 and 3.16 eV for Ce‐NPs; −0.55 and 2.73 eV for Ce‐NRs and −0.38 and 2.56 eV for Ce‐NCs, respectively (Figure 9).…”

“…The absolute electronegativity of CeO 2 was estimated to be 5.59 eV, which is in agreement with the values obtained in literature (5.56 eV). [42] Moreover, the estimated CB and VB position were respectively found to be À 0.98 and 3.16 eV for Ce-NPs; À 0.55 and 2.73 eV for Ce-NRs and À 0.38 and 2.56 eV for Ce-NCs, respectively (Figure 9). According to the UV/Vis data, the CB and VB positions indicate that both the O 2 * À and HO * radicals were generated during the photoreaction.…”

Adsorption and Fenton-like Degradation of Ciprofloxacin Using Corncob Biochar-Based Magnetic Iron–Copper Bimetallic Nanomaterial in Aqueous Solutions

“…Because iron has excellent magnetism and redox properties, it is widely used in various technical fields. However, the activity of iron oxide is low, thus it is the formation of bimetallic oxides by introducing a second metal compound [21]. More OH are produced in the catalytic oxidation reaction due to Cu and its oxides' better redox properties [22].…”

Photo-epoxidation of (α, β)-pinene with molecular O2 catalyzed by a dioxo-molybdenum (VI)-based Metal–Organic Framework

“…Up till now, various homogeneous-and heterogeneous-based metal-oxo catalytic systems (M = O) have been evaluated for the oxidation of pinene, especially the ones based on transition metals (V, Co, Mn, Fe, Ti, Mo, Re) and noble metals (Au, Ru) [9][10][11][12][13]. Although these metal-oxo-based catalysts exhibited a good activity, difficulties associated with the stability of the metal center, the need for a co-reductant or oxidant and a low selectivity toward the desired product are still frequently observed [14]. Molybdenum-oxygen species (Mo = O) represent one of the most examined structures in oxygen atom transfers (OAT) [15,16].…”