Novel triazole derivatives as ecological corrosion inhibitors for mild steel in 1.0 M HCl: experimental & theoretical approach

The present paper illustrates the investigation of two novel ecological triazole derivative corrosion inhibitors, namely ethyl 2-(4-phenyl-1H-1,2,3-triazol-1-yl) acetate [Tria-CO2Et], and 2-(4-phenyl-1H-1,2,3-triazol-1-yl) acetohydrazide [Tria-CONHNH2]. The studied inhibitors were investigated against the corrosion of mild steel in 1.0 M HCl solution using different electrochemical techniques. Potentiodynamic polarization experiments indicated that the [Tria-CO2Et], and the [Tria-CONHNH2] acted as mixed type inhibitors. Electrochemical impedance spectroscopy measurements revealed that both inhibitors presented a high inhibition performance, achieving an inhibition efficiency of 95.3% for [Tria-CO2Et] and 95.0% for [Tria-CONHNH2] at a concentration of 1.0 × 10−3 M. Based on the Langmuir isotherm model and the activation parameters, these triazole derivatives were adsorbed onto a steel surface by physical and chemical bonds. Density functional theory based on B3LYp6-311G(d,p) was also carried out to correlate the inhibition efficiencies obtained experimentally with the theoretical descriptors of the studied molecular structures.