Highly reactive anatase nanorod photocatalysts synthesized by calcination of hydrogen titanate nanotubes: Effect of calcination conditions on photocatalytic performance for aqueous dye degradation and H2 production in alcohol-water mixtures

A series of anatase TiO2 nanorod photocatalysts, denoted herein as xTiO(2) (t) where x = calcination temperature and t = calcination time, were successfully synthesized by calcination of H2Ti3O7 nanotubes at 500-700 degrees C for 10-240 min. SEM, TEM, XRD and BET analyses demonstrated that nanorods with different aspect ratios, crystallite sizes and surface areas (15-93 m(2) g(-1)) could be obtained by varying the calcination conditions. The 600TiO(2) (t) and 700TiO(2) (t) nanorods demonstrated superior photocatalytic activity to Degussa P25 TiO2 for methylene blue photo-oxidation at pH 6, and also superior activity for H-2 production in alcohol-water systems following decoration with Pd, Au or Pd-Au co-catalysts. Under UV excitation (365 nm, 6.5 mW cm(-2)), Pd-Au/ 600TiO(2) (20) afforded H-2 production rates of 37.2, 44.0 and 45.6 mmol g(-1)h(-1) in 10 vol.% ethanol-water, ethylene glycol-water and glycerol-water mixtures, respectively. Co-catalyst activity for the 600TiO(2) (t) and P25 TiO2 photocatalysts followed the order Pd-Au > Pd > Au.