Electrochemical and Gravimetric Studies of the Corrosion Inhibitory Properties of Green Synthesized Copper Oxide Nanoparticles Mediated by Ficus sur for Mild Steel in HCl

Mitigation of mild steel (MS) corrosion in acid medium is imperative to avert enormous economic loss. In this study, copper oxide nanoparticles (CuONPs) were synthesized using Ficus sur leaves extract as an eco-friendly and economical approach. XRD, DLS, FTIR spectroscopy and TEM were employed for characterization. The corrosion inhibitory potential of the synthesized CuONPs for MS in HCl was studied using electrochemical techniques (i.e. EIS and PDP) and gravimetry. The mean crystallite size of CuONPs was 28.4 nm while the hydrodynamic size of CuONPs was 56.7 d.nm, suggesting nanomaterial. The FTIR spectrum showed absorption band around 610 cm−1 which could be due to CuO. TEM image revealed slightly agglomerated spherical nanoparticles with sizes within the nano range. The shift in corrosion potential in the presence of CuONPs was < 85 mV, signifying mixed type behavior. EIS studies revealed an upsurge in charge transfer resistance from 7.3 cm2 (devoid of inhibitor) to 81.7 cm2 when 1000 ppm of CuONPs was introduced. The highest inhibition efficiency (IE) obtained from PDP (86.5 %) and EIS (91.1 %) were achieved in the presence of 1000 ppm CuONPs. The adsorption of CuONPs on MS surface obeyed Langmuir isotherm.