Synthesis and Application Insights of New Phosphate Materials A2MnP2O7 (A = Na, K, Li) as Corrosion Inhibitors

Abstract

This study comprehensively characterizes synthesized phosphate materials, specifically A2MnP2O7 (where A represents Na, K, or Li), utilizing the X-ray diffraction (XRD) and infrared (IR) spectroscopy techniques. The XRD results corroborate the crystalline nature of these compounds, while the IR spectra disclose pivotal structural characteristics, including the bent geometry of the POP bridge. A significant observation is the mismatch of specific IR bands, suggesting a non-centrosymmetric arrangement in the A2MnP2O7 crystal lattice. The synthesized materials were evaluated as corrosion inhibitors for mild steel (MS) in 3 wt.% NaCl. Electrochemical assessments indicate that these materials act as mixed-type inhibitors, demonstrating high inhibition efficiencies (η%), reaching peak values of 88.3% for Na2MnP2O7, 87% for K2MnP2O7, and 86.7% for Li2MnP2O7 at a concentration of 10−3 mol/L. The study also elucidates the thermodynamic and kinetic parameters dictating the inhibition phenomena. Additionally, scanning electron microscopy (SEM) was employed to examine the surface morphology of mild steel in the presence of these inhibitors.