Bio-hydrothermal synthesis of ZnO nanoparticles using Vateria indica leaf extract and their inhibitory efficacy on carbon steel corrosion

Safeguarding carbon steel against intense corrosion in harsh environments is essential for maintaining reliability, security, and long-term functionality across multiple industries. This study reports a green hydrothermal synthesis of ZnO nanoparticles using Vateria indica leaf extract as a natural reducing and stabilizing agent, eliminating the need for toxic reagents and energy-intensive processes. Electrochemical studies in 1 M HCl demonstrated a maximum inhibition efficiency of 99% at 1500 ppm, significantly reducing corrosion current density through a predominantly cathodic mixed-type mechanism. The formation of a protective adsorbed film is evidenced by surface characterization using scanning electron microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). The nanoparticles adsorb onto the steel surface via combined physisorption and chemisorption, following the Langmuir adsorption isotherm, and form a compact protective film. These green ZnO-NPs exhibit strong potential as a sustainable strategy for mitigating acid-induced corrosion.