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Abstract
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In this research, the electrochemical oxidation of thiophene at platinum and dimensionally stable anode (DSA) electrodes as low oxidation power anodes and at lead/lead oxide (Pb/PbOx) and boron-doped diamond (BDD) electrodes as high oxidation power anodes was comprehensively studied by determining the rate and degree of the electrochemical thiophene oxidation, the Coulombic efficiency (CE), and the selectivity of polar product formation [thiophene-2-one and 3-hydroxythiophene-2(3H)-one (Thyox)]. The DSA showed the best performance among the low oxidation power electrodes, with a selectivity of 84.54% toward Thyox formation, a product formation rate of 224.51 mmol/(h m2), a CE of 23.04%, and thiophene conversion of 97.96% in 0.5 M H2SO4 solution for 3 h in ambient temperature. The conversion of thiophene was approximately the same using Pb/PbOx and BDD (about 92%), but Pb/PbOx yielded higher selectivity and product formation rate for Thyox formation [73.68% and 117.72 mmol/(h m2), respectively]. However, CE of BDD (62%) was nearly 3 times greater than that of Pb/PbOx at lower potentials. The experimental results can provide a clear decision in the exploitation of oxidation processes at the industrial scale and could be easily extended to other thiophenic compounds.
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