guardians against corrosion: exploring diphenylpyrazoles through experimental and dft analysis

This study investigates the potential of 5-amino-1,3-diphenylpyrazole and nitrogen-enriched 5-hydroxy-1,3-diphenylpyrazole to inhibit corrosion of mild steel in acidic environments. a comprehensive approach combining weight loss measurements and density functional theory (dft) calculations was employed to analyze the inhibitory effect under various concentrations, immersion times, and temperatures. at an optimal concentration of 0.5 mm, 5-amino-1,3-diphenylpyrazole displayed an impressive 94.7% inhibition efficiency, while 5-hydroxy-1,3-diphenylpyrazole achieved 86.4% efficiency at 303 k after 10 hours of exposure. both compounds exhibited a mixed-type inhibition behavior, with increasing efficiency observed at higher concentrations. dft calculations provided insights into the interaction between the molecules and the metal surface, along with their electronic properties, aiding in understanding the corrosion inhibition process. the investigation revealed that langmuir isotherms govern the adsorption mechanism, and the calculated thermodynamic parameters suggest a complex interplay at the metal/solution interface, involving both chemisorption and physisorption. these findings provide valuable knowledge about the mechanisms of corrosion inhibition by these molecules, paving the way for the development of effective strategies to protect mild steel in corrosive environments.