Green synthesis of Ca–CuO nanocomposites using Lobularia maritima: Multifunctional photocatalytic, antioxidant, and anti-corrosion applications

Calcium–copper oxide (Ca–CuO) nanocomposites were synthesized through a sustainable phytogenic approach using Lobularia maritima extract as a natural reducing and stabilizing agent. The green route yielded a stable, well-crystallized product confirmed by structural, morphological, and spectroscopic analyses. The nanocomposites displayed remarkable multifunctionality. In photocatalysis, they achieved 96 % degradation of Malachite Green and 93 % degradation of Crystal Violet within 90 min under visible light at pH 12 with an 8 mg dose. In corrosion protection studies, the charge-transfer resistance increased from 50 Ω·cm² (blank) to 1187 Ω·cm² at 30 mg, corresponding to an inhibition efficiency of 95.8 % from electrochemical impedance spectroscopy and 77.1 % from potentiodynamic polarization. Antioxidant assays revealed strong radical-scavenging potential, with DPPH and ABTS inhibition values of 89.91 % and 89.52 %, respectively, at the tested concentration and showed strong antioxidant activity at fixed doses (DPPH 78.5, ABTS 84.3, TAC 91.2 µg mL⁻¹). These findings demonstrate the potential of Lobularia maritima –derived Ca–CuO nanocomposites as efficient, eco-friendly materials for wastewater treatment, corrosion protection, and free-radical neutralization.