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Inverse relation between the catalytic activity and catalyst concentration for the ruthenium(0) nanoparticles supported on xonotlite nanowire in hydrogen generation from the hydrolysis of sodium borohydride

2016-12-01
Akbayrak, Serdar
Özkar, Saim
Ruthenium(0) nanoparticles supported on xonotlite nanowire (Ru(0)/X-NW) were prepared by the ion exchange of Rua* ions with Ca2+ ions in the lattice of xonotlite nanowire followed by their reduction with sodium borohydride in aqueous solution at room temperature. Ru(0)/X-NW show high catalytic activity and long life time in hydrogen generation from the hydrolysis of sodium borohydride with a turnover frequency value up to 305 min(-1) and a total turnover number of 63,100 mol H-2/mol Ru in hydrogen generation from the hydrolysis of sodium borohydride at 25.0 +/- 0.1 degrees C. Moreover, the catalytic activity of Ru(0)/X-NW shows an inverse dependence on the catalyst concentration. Ru(0)/X-NW at different ruthenium concentrations were characterized by high resolution transmission electron microscopy. The results reveal that Ru(0)/X-NW have tunable particle size depending on the metal concentration. An increase in the mean particle size of ruthenium(0) nanoparticles is observedwhen the metal concentration increases. The smaller particle size distribution at low ruthenium concentrations exhibits higher catalytic activity in hydrogen generation from the hydrolysis of sodium borohydride. The reaction kinetics of the catalytic hydrolysis of sodium borohydride was also studied.