Experimental and theoretical study on corrosion inhibition of mild steel by meso-tetraphenyl-porphyrin derivatives in acid solution

Abstract

The inhibition effect of meso-tetraphenyl-porphyrin (TPPH2), meso-tetra4-methophenyl-porphyrin TPPH2(p-Me), and meso-tetra4-actophenyl-porphyrin (TAcPPH2) on the corrosion of XC52 mild steel in aerated 0.5 M aqueous sulfuric acid solution was studied by potentiodynamic polarization experiments and quantum chemical calculations. Results from potentiodynamic polarization showed that inhibition efficiency of three compounds increased upon increasing of the inhibitor concentration and they are acting as mixed type inhibitors, having dominant anodic reactions. Adsorption of all compounds follows the Langmuir adsorption isotherm with moderate values of free energy of adsorption. Quantum chemical calculation using DFT/B3LYP method confirmed a strong bond between meso-tetraphenyl-porphyrins and mild steel surface. The inhibition mechanism was also determined by the potential of zero charge (PZC) measurement at the metal/solution interface.

Synthesis, characterization, cyclic voltammetry, and molecular docking studies of the antioxidant activities of superoxide anion radicals towards meso-tetramethophenyl-porphyrin and meso-tetrabiphenyl-porphyrin

“…Meso-tetramethophenyl-porphyrin and meso-tetrabiphenyl-porphyrin represent macrocyclic aromatic compounds characterized by an 18π electron structure, composed of four pyrrole subunits interconnected through methine bridges. These compounds exhibit noteworthy electron mobility within the ring, rendering 2 them suitable for diverse applications (Meraghni et al, 2023), including electrochemistry and catalysis (Zuriaga-Monroy et al, 2016), photomedicine (Boutarfaia et al, 2020), and photosynthesis (Zaiz et al, 2012). The nitrogen atoms in these compounds possess the ability to engage in reactions with metal ions, forming stable metalloporphyrin complexes, with transition metal ion complexes being the most extensively studied (Thompson et al, 2018).…”