investigation of different metallic cathodes towards electro-reductive desulfurization of thiophenic compounds

The performance of different metallic cathodes was investigated towards desulfurization efficiency as well as the current efficiency of thiophene and benzothiophene# the electroreductive reactions were carried out in a divided electrochemical cell under the same constant current using chronopotentiometry method for 6 h# the solutions were prepared using 2000 mg l-1 of thiophenic compounds in a 0#5 m h2so4 electrolyte# the cyclic voltammetry of electrodes was measured at 50 mv s-1 before each experiment which showed that 15 ma cm-2 and 25 ma cm-2 is adequate for the electro-reductive desulfurization of the thiophene and benzothiophene# the gc-ms analysis of initial and final samples revealed that electrodes having high h2 evolution overpotential are appropriate ones in terms of desulfurization and current efficiency simultaneously# also, result demonstrated that the order of cathodes in terms of better desulfurization and current efficiency follows as tin, tungsten, zinc, molybdenum and gold electrodes# the tin electrode could achieve maximum desulfurization at the corresponding current efficiency either for thiophene or benzothiophene which were 92#81% at 20#36% for thiophene and 37#24 at 11#74%, respectively# the gc-ms analysis proved the direct desulfurization mechanism for all electrodes during experiments#