Novel sucrose derivative as a thermally stable inhibitor for mild steel corrosion in 15% HCl medium: An experimental and computational study

Metal corrosion is a destructive process for many industrial operations, including oil well acidizing and acid pickling. Previous studies have primarily evaluated the inhibition performance of inhibitors at various temperatures mainly using a simple technique, namely weight loss. Nevertheless, the study of the electrochemical aspects of corrosion inhibition at temperatures above 298 K is of prime importance because corrosion is an electrochemical phenomenon. This research hence aimed to fill this research gap by introducing a novel sucrose derivative as a thermally stable inhibitor (SDCI) for corrosion mitigation of mild steel in a 15% HCl medium. Temperature effects on the inhibition activity of SDCI were investigated using electrochemical tests at 303 K, 323 K, 343 K, and 363 K, which was supported by a comprehensive computational study. According to thermogravimetric analysis, SDCI exhibited a good thermal stability and its molecular structure was stable up to 420 K. The results of electrochemical experiments clarified that temperature plays a critical role in the inhibitory action of SDCI as a shift from primarily cathodic to anodic inhibition mechanisms was observed with the increasing temperature. The contact angle, FT-IR, and UV–visible techniques were used to detect the formation of a protective film and the complex between Fe²⁺ ions and SDCI. Furthermore, the computational results indicated that SDCI has relatively high adsorption energy on the mild steel surface at 303 K and 363 K, which is consistent with the electrochemical data and supports its good inhibition efficiency at high temperatures. These findings have the potential to help researchers to better understand the effect of temperature on the mechanism of inhibitors, both theoretically and experimentally.