Jaloul, Randa2026-02-042026-02-042026-02-04http://hdl.handle.net/10393/51346https://doi.org/10.20381/ruor-31730Repurposing CO₂ in the atmosphere is a key strategy to combat global warming and reduce fossil fuel capture conditions. Molecular catalysts (metal complex catalysts) can be precisely designed at the molecular level to accelerate CO₂ conversion reactions. Different classes of metal complexes catalyzed the reduction of CO₂ with astonishing efficiency and selectivity. Recently, numerous semiconductor photocatalysts were designed in heterostructure systems, which are composed of complex components of semiconductor and metal. Homogeneous metal complexes can be employed to study reaction processes more straightforwardly than the heterogeneous method. This study focuses mainly on proposed mechanisms driving the photochemical reduction of CO₂ initiated by ruthenium complexes. Ruthenium complexes mainly produce HCOOH and H₂, and the product selectivity is highly dependent on the reaction conditions. This study investigated complexes of ruthenium with bidentate phosphino-aminopyridine ligands for their photocatalytic activity. Catalysis was carried out using as solvent, 4 mL of a solution of this complex in N, N-dimethylacetamide (DMA), with [Ru(bpy)₃]²⁺ as a photosensitizer, and 1 mL of triethanolamine (TEOA) as a sacrificial agent in the presence of carbon dioxide. LEDs (1050 mW, 700 mA, 3.4 x 10⁻⁸ mol photons/sec) at 450 nm wavelength were used to irradiate the reaction mixture with visible light. The results show that the photocatalytic activity is greatly enhanced by the presence of the ligand group. NMR spectroscopy and gas chromatography confirmed the generation of carbon monoxide (CO), hydrogen (H₂), and formic acid (HCOOH) via the photocatalytic reduction of CO₂ catalyzed by ruthenium complexes. Graphical Abstract: Ru-based complexes synthesized with various substituents on the N-(diphenylphosphino)-2-aminopyridines ligand were investigated for their behaviour in photocatalytic CO₂ reduction.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/PhotocatalyticElectrocatalyticHomogeneous CatalystsThesis