Electrochemical behaviour of iron in H2SO4 containing thiophene

The effect of thiophene on the corrosion of iron in H2SO4 has been studied by double-layer capacity and polarisation measurements. No change in mechanism was observed by the addition of thiophene, but a significant decrease in the rate of hydrogen evolution was observed. The inhibitor concentration was found to have a significant influence on the behaviour of the open-circuit capacitance, while the change in potential was small. The results show that thiophene is adsorbed on the iron surface according to the Temkin isotherm. The inhibitor efficiencies, as determined from current-voltage curves and the weight loss method, were consistent.