Spectroscopic and magnetic properties of Cu(II) complexes with selected biologically important ligands

Green Inhibition of Corrosion of Aluminium Alloy 5083 by Artemisia annua L. Extract in Artificial Seawater

Plant extracts are increasingly being examined in the corrosion inhibition of metal and alloys in various environments due to their potent antioxidant properties. The use of Artemisia annua L. aqueous extract (AAE) as an aluminium alloy 5083 (ALA) corrosion inhibitor in artificial seawater (ASW) was investigated using electrochemical tests and spectroscopy tools, while the active biocompounds found in AAE were analyzed using high-performance liquid chromatography (HPLC). Electrochemical results showed that AAE acts as an anodic inhibitor through the physisorption (ΔG ≈ –16.33 kJ mol−1) of extract molecules on the ALA surface, thus reducing the active sites for the dissolution of the alloy in ASW. Fourier-transform infrared spectra confirmed that phenolic acids found in AAE formed the surface layer that protects ALA against the corrosive marine environment, while HPLC analysis confirmed that the main phytoconstituents of AAE were chlorogenic acid and caffeic acid. The inhibition action of phenolic acids and their derivatives found in the AAE was based on the physisorption of caffeic acid on the ALA surface, which improved physicochemical properties of the barrier film and/or conversion of Al3+ to elemental aluminium by phenolic acids as reducens, which slowed down the diffusion rate of Al3+ to or from the ALA surfaces. The protective effect of the surface layer formed in the presence of AAE against ASW was also confirmed by inductively coupled plasma–optical emission spectrometry (ICP-OES) whereby the measured concentration of Al ions after 1 h of immersion of ALA in the pure ASW was 15.30 μg L−1 cm−2, while after the addition of 1 g L−1 AAE, the concentration was 3.09 μg L−1 cm−2.

Low-Temperature Stable α-Phase Inorganic Perovskite Compounds via Crystal Cross-Linking

Inorganic perovskite compounds hold promise to improve the stability of perovskite solar cells (PSCs). However, the phase instability and high annealing temperature process of these metastable structural polymorphs such as α-phase CsPbI_{3- x}Br _x hinder their further development. Herein, we demonstrated the successful reduction of temperature from 250 to 100 °C during the growth of stable and high-crystallinity α-phase CsPbI₂Br via crystal cross-linking. 4-Aminobenzoic acid (ABA) was used as a nonvolatile additive with slight solubility in water to bridge the adjacent CsPbI₂Br to form a grain-interconnected film. The interaction between ABA and perovskite grains leads to the growth of highly crystalline perovskite films. The optimized PSC based on ABA-incorporated CsPbI₂Br using a TiO₂/Al₂O₃/NiO/carbon architecture exhibits an efficiency of 8.44%. More importantly, the additive enables significant improvement of phase stability against moisture. The good performance highlights the chemical modification via cross-linking to achieve efficient and stable inorganic perovskite devices.