Synthesis and photocatalytic activity of K2CaNaNb3O10, a new Ruddlesden–Popper phase layered perovskite

Abstract

A new three-layer perovskite oxide with the Ruddlesden–Popper (R–P) phase, K₂CaNaNb₃O₁₀, and its protonated form were synthesised and their photocatalytic performance was compared to that of KCa₂Nb₃O₁₀ or the protonated form with the Dion–Jacobson (D–J) structure in terms of H₂ and O₂ evolution. K₂CaNaNb₃O₁₀ exhibited a higher activity for O₂ evolution than KCa₂Nb₃O₁₀ when IO₃⁻ was used as an electron acceptor. However, protonated KCa₂Nb₃O₁₀ worked more efficiently than protonated K₂CaNaNb₃O₁₀ when Fe³⁺ was used as an electron acceptor. In both cases, it is likely that the stronger affinity of water with the interlayer contributed to higher performance. The activity of the D–J material for H₂ evolution was much lower when 1-propanol was used as an electron donor than when methanol was used. In contrast, the R–P phase exhibited a similar activity regardless of the electron donor. These results indicate that the interlayer space acts as an oxidation site, so that better access of the electron donor to the interlayer is an important factor that enhances photocatalytic activity.