Synthesis and Characterization of a New Nanocatalyst Based on Keggin-Type Polyoxovanadate/Nickel-Zinc Oxide, PV₁₄/NiZn₂O₄, as a Potential Material for Deep Oxidative Desulfurization of Fuels

Abstract

On account of the undesirable sulfur compounds in gasoline, a new heterogeneous catalyst (PV 14 /NiZn 2 O 4 ) was synthesized successfully by immobilizing Keggin-type polyoxovanadate (K 9 [PV 14 O 42 ]·11H 2 O) (abbreviated as PV 14 ) on the surface of nickel-zinc oxide (NiZn 2 O 4 ). The physicochemical characteristics of the nanocomposite as well as its individual constituents were identified by Fourier transform infrared (FTIR), ultraviolet–visible (UV–vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and thermogravimetric analysis-differential thermogravimetry (TGA-DTG) techniques. The characterization outcomes indicated that PV 14 was uniformly dispersed over the surface of NiZn 2 O 4 . The PV 14 /NiZn 2 O 4 nanocatalyst was served for catalytic oxidative desulfurization (Cat-ODS) of sulfur compounds in real gasoline and model fuel oils (MFOs) with 3 mL of H 2 O 2 /AcOH oxidizing agent (volume ratio of 2:1). The optimum conditions for the Cat-ODS process were obtained using 0.1 g of the PV 14 /NiZn 2 O 4 nanocatalyst at 35 °C after 60 min under atmospheric pressure. Based on the experimental results described above, it was observed that the total concentration of sulfur present in authentic gasoline underwent a substantial reduction from 0.4987 to 0.0143 wt %, denoting an efficiency of 96%. Moreover, the elimination of sulfur from MFOs, which are difficult to remove, could reach up to 95% at the same reaction conditions. Furthermore, the catalytic efficacy of PV 14 /NiZn 2 O 4 was sustained for five cycles, without any notable reduction in its performance. Finally, the mechanism of Cat-ODS was proposed through the generation of oxo–peroxo intermediate species.

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