Keynote, Affordable and Clean Energy (SDG 7), Responsible Consumption and Production (SDG 12)
Photocatalytic studies of ruthenium-based dyes for solar cells: A precursor for GH 2 production from H 2 O V Uahengo * , J Naimhwaka, P Endjala, L Daniel Department of Physics, Chemistry and Material Chemistry, University of Namibia, 340 Mandume Ndemufayo Avenue, Windhoek, 9000, Namibia. * Corresponding author. Tel: +264 61 206 3465. E-mail address: vuahengo@unam.na Ruthenium bipyridyl-based complexes exhibit excellent photocatalytic properties, within the functional wavelength range. Based on the N 3 DSSC family, ruthenium bipyridyl complexes exhibit a tunable metal- to-ligand charge transfer (MLCT) transition, in the visible light region of the spectrum, through which the photoelectric charge is injected into the conduction band of TiO 2 [1] . Thus, by manipulating HOMO-LUMO gap through tuning techniques, the N 3 -drived ruthenium-based complexes were designed and, their resulting properties investigated. The ruthenium complexes were applied towards the photocatalytic hydrogen production from water [2] . Judicious molecular engineering of ruthenium bipyridyl complexes allows extended/expanded functional absorption range (to NIR) and/or increased molar absorptivity, both of which resulted into enhanced quantum efficiency, thus high IPCE. The manipulation of optoelectronic properties of ruthenium dye structures is generally tailored for targeted applications, such as photocatalytic splitting of water for GH 2 production [1,2] , biological activities [3] and lately the CO 2 reduction to CO [4] . Tuning the ruthenium molecular systems ranges from varying ruthenium nuclear centers (mononuclear vs binuclear), bridging ligands (electronic coupling, for CT) and the antennae effect [5,6] , with both yielding enhanced charge transfer mechanisms (MLCT, MMCT, etc.), resulting into increased visible- light photoinduced hydrogen evolution from water.
Key words: Photocatalysis, Charge-Transfer, Ruthenium, Water Splitting, Hydrogen Evolution References 1. X. Zhang et al, Chem - A Eur J. (2012), 17;18(38):12103–11. 2. U. Veikko et al., Spectrochimica Acta Part A, 105 (2013) 539–544 3. Y. Zhang et al, J Coord Chem. (2018) 8972:1–11.
4. T. Ishizuka, et al, J Am Chem Soc. (2023);145(42):23196–204. 5. A. Monari, et al, J Phys Chem A. (2011);115(15):3596–603. 6. V. Uahengo, et al, Polyhedron, (2019), 173:114106.
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