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چکیده
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Historically and presently there have been two general families of WOCs, heterogeneous and homogeneous, each with strong assets and liabilities [1]. Oxidative stability requires that a ligand(s) and the entire WOC structure be developed that is carbon-free, and more generally, stable to combustion [2]. Although targeted electrode modification is well established [3], our research has a distinctive novelty using fully inorganic water oxidation catalyst (WOC) in combination with carbon nanotubes (CNTs) to facilitate electron transfer in electrochemical reactions and to increase stability of a modified electrode. We attempted to use water soluble Rb8Cs2[(SiW10O36)2Ru4O6(OH2)4] salt as a catalyst to modify GC electrode. Nanoparticles of Rb8Cs2[(SiW10O36)2Ru4O6(OH2)4] (NP-POM) were prepared [4] and adsorbed on F-MWNTs. TEM imaging data confirmed that the Ru4-POMs nanoparticles are adsorbed on the surface of the F-MWNTs and used for modification of GC electrode. The anodic current on this electrode is higher compared with that of on the electrode modified by a combination of Ru4- POM (TBA salt) and F-MWNTs. Thus, the GC/(F-MWNT)/(NP-POM) electrode seems to be catalytically active in water oxidation. Therefore, a bulk electrolysis was carried out using the graphite/(F-MWNT)/(Ru4-POM) electrode varying pH, supporting electrolyte (NaCl versus NaNO3) and applied potential at very low over potential. Dioxygen was measured by gas chromatography (GC), and the O2 yield was calculated based on total charge.Under these experimantal conditions the O2 yield remains constant (~69%) during electrolysis. The modified electrode was quite stable and the efficiency of electrolysis strongly depends on applied potentials.
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