Exploring novel anticorrosive applications: Solid-state synthesis and characterization of Li2CuP2O7 and Na2CuP2O7 pyrophosphates

Abstract

This work shows the importance of inorganic materials Li₂CuP₂O₇ and Na₂CuP₂O₇, especially the effect of Li and Na atoms, in their use as inhibitors that preserve Mild steel in 1.0 M HCl solution. Lithium and Sodium copper (II) pyrophosphate crystals were synthesized through solid-state reaction and characterized using Infrared Spectroscopy technique (IR), as well as X-ray diffraction (XRD). The infrared spectrum of compounds Li₂CuP₂O₇ and Na₂CuP₂O₇ was captured and interpreted, revealing a bent POP bridging angle within these compounds. Furthermore, the inhibitory effect of these pyrophosphates on Mild steel corrosion in a 1.0 M HCl solution was studied. During this investigation, electrochemical techniques alongside surface examination through SEM and EDX. The experimental findings demonstrated that Li₂CuP₂O₇ and Na₂CuP₂O₇ act as effective inhibitors, with inhibition efficiency (η_PP %) rising as the inhibitor concentration increases. At a concentration of 10⁻³ M, Li₂CuP₂O₇ exhibited a remarkable inhibition efficiency of 93 %, which appears to be mixed-type inhibitors.