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Enhanced Visible Light-Driven Photocatalytic Water-Splitting Reaction of Titanate Nanotubes Sensitised with Ru(II) Bipyridyl Complex.

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Malizia, Mauro 
Scott, Stuart A 
Torrente-Murciano, Laura 
Boies, Adam M 
Aljohani, Talal A 


The ion exchange of Na+ cations was used to photosensitise titanates nanotubes (Ti-NTs) with tris(2,2'-bipyridine)ruthenium(II) cations (Ru(bpy)32+); this yielded a light-sensitised Ti-NTs composite denoted as (Ru(bpy)3)Ti-NTs, exhibiting the characteristic absorption of Ru(bpy)32+ in visible light. Incident photon-to-current efficiency (IPCE) measurements and the photocatalytic reduction of methyl viologen reaction confirmed that in the photosensitisation of the (Ru(bpy)3)Ti-NTs composite, charge transfer and charge separation occur upon excitation by ultraviolet and visible light irradiation. The photocatalytic potential of titanate nanotubes was tested in the water-splitting reaction and the H2 evolution reaction using a sacrificial agent and showed photocatalytic activity under various light sources, including xenon-mercury lamp, simulated sunlight, and visible light. Notably, in the conditions of the H2 evolution reaction when (Ru(bpy)3)Ti-NTs were submitted to simulated sunlight, they exceeded the photocatalytic activity of pristine Ti-NTs and TiO2 by a factor of 3 and 3.5 times, respectively. Also, (Ru(bpy)3)Ti-NTs achieved the photocatalytic water-splitting reaction under simulated sunlight and visible light, producing, after 4 h, 199 and 282 μmol×H2×gcat-1. These results confirm the effective electron transfer of Ru(bpy)3 to titanate nanotubes. The stability of the photocatalyst was evaluated by a reuse test of four cycles of 24 h reactions without considerable loss of catalytic activity and crystallinity.


Peer reviewed: True

Publication status: Published


dye-sensitized photocatalyst, hydrogen evolution reaction, ion exchange, photocatalysis, solar simulated light, titanate nanotubes, tris(2,2′-bipyridine)ruthenium(II), water splitting

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Nanomaterials (Basel)

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King Abdulaziz City for Science and Technology (20-0170)