ABSTRACT
The widespread use of hydrogen as a vehicle fuel has prompted us to develop a new nanocomposite by immobilizing of tin ferrite nanoparticles (SnFe2O4) on the surface of multi-walled carbon nanotubes (abbreviated as MWCNTS) for the first time. The prepared nanocomposite powder (SnFe2O4@MWCNTS) was investigated utilizing various microscopy and spectroscopy methods, such as FT-IR, XRD, SEM, EDX, and BET techniques. Moreover, the electrochemical property of SnFe2O4@MWCNTS nanocomposite was investigated by cyclic voltammogram (CV) and charge-discharge chronopotentiometry (CHP) techniques. A variety of factors on the hydrogen storage capacity, such as current density, surface area of the copper foam, and the influence of repeated hydrogen adsorption-desorption cycles were assessed. The electrochemical results indicated that the SnFe2O4@MWCNTS has high capability and excellent reversibility compared to SnFe2O4 nanoparticles (NPs) for hydrogen storage. The highest hydrogen discharge capability of SnFe2O4@MWCNTs was achieved â¼ 365 mAh/g during the 1st cycle, and the storage capacity enhanced to â¼ 2350 mAh/g at the end of 20 cycles using a current of 2 mA. Consequently, the SnFe2O4@MWCNTS illustrated great capacity as a prospective active material for hydrogen storage systems.
ABSTRACT
From the environmental protection and human health perspectives, the design and synthesis of efficient and reusable oxidative desulfurization nanocatalysts has always been sought after by scientists and industries. In this regard, a new heterogeneous nanocatalyst (V-SPM@PANI@CH) was synthesized by immobilizing Keggin-type vanadium-substituted phosphomolybdate ([PVMo11O39]4-) (named V-SPM) clusters on the surface of polyaniline (PANI) and chitosan (CH) polymers. The features of the assembled nanocatalyst were detected by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, and energy-dispersive X-ray spectroscopy techniques in detail. The XRD studies indicated that the average crystallite size of V-SPM@PANI@CH was estimated to be about 36 nm. The catalytic performance of V-SPM@PANI@CH was investigated in the extractive and catalytic oxidation desulfurization (ECOD) procedure of real and thiophenic model gasoline by H2O2/AcOH (volume proportion of 2:1) as an oxidizing system. The optimal desulfurization conditions for ECOD reactions were as follows: 50 mL of model/real gasoline, 0.1 g of V-SPM@PANI@CH, reaction time of 60 min, and reaction temperature of 35 °C. Under the experimental conditions outlined above and the designed ECOD system, the content of sulfur in real gasoline could decline from 0.4985 to 0.0193 wt %, which corresponds to an efficiency of 96%. Moreover, the removal percentage of aromatic hydrocarbons, including thiophene (Th), benzothiophene (BT), and di-benzothiophene (DBT) as model fuels decreases in the order of DBT ≥ BT > Th under identical operating conditions. High catalytic activity was maintained with only a slight loss during five cycles. This work offers the ECOD system (V-SPM@PANI@CH/AcOH/H2O2) for the desulfurization of liquid fuels, which had a great repercussion on the ECOD efficiency.
