Electrochemical hydrogenation and desulfurization of thiophenic compounds over MoS2 electrocatalyst using different membrane-electrode assembly

Desulfurization-hydrogenation of thiophene and benzothiophene in hexadecane as a model diesel fuel was studied through a divided cell with the incorporation of the membrane electrode assembly (MEA) under different current density at a constant charge. The reduction of thiophenic compounds was investigated using prepared MoS2 nano-electrocatalyst and Nafion (commercial proton exchange membrane) and synthesized sulfonated poly ether ether ketone, SPEEK. The MoS2 electrocatalyst was characterized by field emission scanning electron microscopy and X-ray diffraction, which confirmed the formation of ball-like nano-thread of MoS2 with the size of 23-25 nm. Also, the electrocatalyst and/or MEA was electrochemically analyzed by cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. The gas chromatography-mass spectroscopy analysis of reactants and products revealed the direct desulfurization on thiophene reduction process and desulfurization along with desulfurization pathway on benzothiophene reduction experiment. Maximum desulfurization efficiency of 79.6% at 20 mA cm-2 and 51.5% at 30 mA cm-2 under the constant charge of 300 C was obtained for thiophene using MoS2-Nafion and MoS2-SPEEK system respectively. Moreover, maximum hydrogenation and desulfurization efficiency of 28% and 59.1% occurred at 50 mA cm-2 and 70 mA cm-2 respectively for Benzohiophene-Nafion system under the constant charge of 400 C. distribution of products affirmed the more contribution of desulfurization reaction at higher current density against the hydrogenation process at lower current density.

کلیدواژه ها:

Hydrogenation ، Desulfurization ، Thiophenic ، MoS2 electrocatalyst ، Membrane-electrode assembly