Preparation of novel SrTiO3:Rh/Ta photocatalyst by spray pyrolysis and its activity for H2 evolution from aqueous methanol solution under visible light

SrTiO3:Rh/Ta powder was prepared by spray pyrolysis from polymeric precursors containing citric acid and ethylene glycol. Co-doping Ta into SrTiO3:Rh increased the presence of Rh3+ in the host material. The retention of balanced charges by the substitution of two Ti4+ ions in the host material by one ion each of Rh3+ and Ta5+ enhanced hydrogen evolution from aqueous methanol solution under visible light irradiation (λ > 415 nm) by 3.5 times (to 531 μmol h−1) and reduced the induction period by 50% (to 1 h), when compared with SrTiO3:Rh. Thorough mixing of the multi-component spray pyrolysis precursor solution resulted in highly dispersed Rh ions and porous photocatalyst particles, which showed enhanced hydrogen evolution rate.

► A novel photocatalyst of SrTiO3:Rh/Ta was developed for the first time.
► Ta5+ enhanced the formation of Rh3+ and suppressed the formation of Rh4+.
► Maintaining the charge balance is favorable for photocatalytic H2 evolution.
► H2 evolution rate was increased by adding Ta5+ and polymeric additives.