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

Abstract

A series of anatase TiO2 nanorod photocatalysts, denoted herein as xTiO2(t) where x = calcination temperature and t = calcination time, were successfully synthesized by calcination of H2Ti3O7 nanotubes at 500–700 °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 m2 g−1) could be obtained by varying the calcination conditions. The 600TiO2(t) and 700TiO2(t) nanorods demonstrated superior photocatalytic activity to Degussa P25 TiO2 for methylene blue photo-oxidation at pH 6, and also superior activity for H2 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/600TiO2(20) afforded H2 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 600TiO2(t) and P25 TiO2 photocatalysts followed the order Pd-Au > Pd > Au.