Novel benzothiophene based catalyst with enhanced activity for glucose electrooxidation

Abstract Thiophene based heterocyclic compounds plays important roles in organic chemistry due to their unexpected properties. Herein, novel benzothiophene derivatives (6A-F) are synthesized via Sonogashira coupling, iodocyclization reaction, Suzuki-Miyaura coupling and condensation reactions. After characterization of design molecules, their glucose electrooxidation activities are investigated. Electrochemical measurements are performed by cyclic voltammetry, chrono amperometry, and electrochemical impedance spectroscopy in 1 M KOH +0.5 M C6H12O6 solution. This results show that the highest performance organic-based catalysts is obtained as 0.729 mA/cm2 (3.345 mA/mg) for the 2-(4-(2-pentylbenzo [b]thiophen-3-yl)benzylidene)malononitrile (6B). Furthermore, 6B catalyst is shown long term stability, the best current density value (1.151 mA cm−2), and the best transfer resistance load between organic-based catalysts. As a result, it is clear that these benzothiophene derivatives are promising organic based catalyst, an alternative to the expensive Pd and Pt based metal catalyst, for direct glucose fuel cell anode.