Visible light assisted hydrogen generation from complete decomposition of hydrous hydrazine using rhodium modified TiO2 photocatalysts

Hydrogen is considered to be an ideal energy carrier, which produces only water when combined withoxygen and thus has no detrimental effect on the environment. While the catalytic decomposition ofhydrous hydrazine for the production of hydrogen is well explored, little is known about its photocatalyticdecomposition. The present paper describes a highly efficient photochemical methodology for the productionof hydrogen through the decomposition of aqueous hydrazine using titanium dioxide nanoparticlesmodified with a Rh(I) coordinated catechol phosphane ligand (TiO2–Rh) as a photocatalyst under visiblelight irradiation. After 12 h of visible light irradiation, the hydrogen yield was 413 μmol g−1 cat with a hydrogenevolution rate of 34.4 μmol g−1 cat h−1. Unmodified TiO2 nanoparticles offered a hydrogen yield of83 μmol g−1 cat and a hydrogen evolution rate of only 6.9 μmol g−1 cat h−1. The developed photocatalystwas robust under the experimental conditions and could be efficiently reused for five subsequent runswithout any significant change in its activity. The higher stability of the photocatalyst is attributed to thecovalent attachment of the Rh complex, whereas the higher activity is believed to be due to the synergisticmechanism that resulted in better electron transfer from the Rh complex to the conduction band of TiO2