In this paper, we emphasized the dual application of Cu-modified vertically aligned TiO₂ nanotube arrays as photocatalyst and a relative humidity sensor. The TiO₂ nanotube arrays were obtained by anodization of the titanium layer prepared using radio frequency magnetron sputtering (RFMS) and modified with different copper concentrations (0.5, 1, 1.5, and 2 M) by a wet-impregnation method. The sample modified with 2 M Cu(NO₃)₂ solution showed the highest efficiency for the NH₃ photocatalytic degradation and the most pronounced humidity response in comparison to the other studied samples. In order to investigate the structure and impact of Cu modification, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) were used. The photocatalytic activity and the kinetic study of ammonia oxidation were studied in a mini-photocatalytic wind tunnel reactor (MWPT), while relative humidity sensing was examined by impedance spectroscopy (IS). Higher NH₃ oxidation was a direct consequence of the increased generation of ^•OH radicals obtained by a more efficient photogenerated charge separation, which is correlated with the increase in the DC conductivity.

Molybdenum materials derived from acyl-hydrazones were synthesised. Structural changes and electrical properties were analyzed by in situ impedance spectroscopy. Catalytic performance in linalool oxidation was tested and compared to vanadium analogs.

This study examines the influence of ligand design on the structural, optical, and electrical properties of copper-based coordination complexes. Ligands H₂L¹ and H₂L² were synthesized via the reaction of 5-nitrosalicylaldehyde with 2-hydroxy- or 4-hydroxybenzhydrazide. H₄L³ was obtained from the reaction of carbohydrazide and salicylaldehyde, while H₄L⁴ was prepared by condensing 4-methoxysalicylaldehyde with thiocarbohydrazide. The research focuses on two key design elements: (1) the effect of hydroxyl group positioning on the aroyl ring in hydrazide ligands (H₂L¹ vs. H₂L²) and (2) the impact of carbonyl versus thiocarbonyl groups and aldehyde substituents in hydrazone ligands (H₄L³ vs. H₄L⁴). The resulting complexes, [Cu₂(L¹)₂], [Cu₂(L²)₂(MeOH)₃], [Cu₂(L³)(H₂O)₂], and [Cu₂(L⁴)(H₂O)₂], were synthesized and characterized using attenuated total reflectance infrared (IR-ATR) spectroscopy, thermogravimetric analysis (TG), and UV-Vis diffuse reflectance spectroscopy. Their electrical properties were investigated using solid-state impedance spectroscopy (IS). The crystal and molecular structure of the complex [Cu₂(L²)₂(MeOH)₃]∙MeOH was determined by single-crystal X-ray diffraction (SCXRD). This study underscores the pivotal role of ligand modifications in modulating the functional properties of coordination complexes, offering valuable insights for the advancement of materials chemistry.

This study examines the influence of ligand design on the structural, optical, and electrical properties of copper-based coordination complexes. Ligands H2L1 and H2L2 were synthesized via reaction of 5-nitrosalicylaldehyde with 2-hydroxy- or 4-hydroxybenzhydrazide, respectively. H4L3 was obtained from the reaction of carbohydrazide and salicylaldehyde, while H4L4 was prepared by condensing 4-methoxysalicylaldehyde with thiocarbohydrazide. The research focuses on two key design elements: (1) the effect of hydroxyl group positioning on the aroyl ring in hydrazide ligands (H2L1 vs. H2L2) and (2) the impact of carbonyl versus thiocarbonyl groups and aldehyde substituents in hydrazone ligands (H4L3 vs. H4L4). The resulting complexes, [Cu2(L1)2], [Cu2(L2)2]∙3MeOH, [Cu2(L3)(H2O)2], and [Cu2(L4)(H2O)2], were synthesized and characterized using attenuated total reflectance infrared (IR-ATR) spectroscopy, thermogravimetric analysis (TG), and UV-Vis diffuse reflectance spectroscopy. Their electrical properties were investigated using solid-state impedance spectroscopy (IS). This study underscores the pivotal role of ligand modifications in modulating the functional properties of coordination complexes, offering valuable insights for the advancement of materials chemistry.