Synthesis and performance of layered perovskite-type H-ABi2Ta2O9 (A = Ca, Sr, Ba, K0.5La0.5) for photocatalytic water splitting

Novel photocatalysts, protonated layered perovskite oxides H-ABi2Ta2O9 (A = Ca, Sr, Ba, K0.5La0.5) for overall water splitting were synthesized by ion exchange with acid treating. The characterization by XRD, HRTEM indicated that all of ABi2Ta2O9 (A = Ca, Sr, Ba, K0.5La0.5) were able to form new single-phase protonated layered oxides. The measurement of photocatalytic activity showed every protonated layered oxide could overall split water into H2 and O2, although the ratios of H2 and O2 are unstoichiometric. The sequence of photocatalytic H2 production is HCBT(107.0 μmol/h) < HBBT(119.5 μmol/h) < HSBT(162.7 μmol/h) < HKLBT(189.3 μmol/h). The difference of ionic radius of cations in interlayer influenced the band gaps, and resulted in the distinction of photocatalytic activity. Pt loading enhanced apparently the photocatalytic activity. Among all of photocatalysts in this study, 0.1 wt%Pt/HSBT showed the highest photocatalytic activity for H2 evolution, reaching 491 μmol/h.