Silver Exchange of Layered Metal Oxides and Their Photocatalytic Activities

Abstract

Layered Dion–Jacobson phases RbLaNb2O7 and RbA2Nb3O10 (A = Ca, Sr) and the Ruddlesden–Popper phase Rb2La2Ti3O10 were prepared by solid-state methods at a reaction time of 50 h and a temperature of 1100 °C. The products were silver-exchanged within a AgNO3 flux at a reaction time of 24 h and a temperature of 250 °C. Substitution of silver cations into the interlayer spacing of the layered structures is found to decrease the optical bandgap sizes on average by ∼0.5 to ∼1.0 eV. The products were found by scanning electron microscopy (SEM) to exhibit irregularly shaped platelet morphologies with an average size of ∼1–5 μm across their lateral dimensions and stepped edges ranging from ∼20 to ∼300 nm in height. Significant increases in photocatalytic hydrogen production rates for all silver-exchanged products were observed. The silver-exchanged RbA2Nb3O10 layered structures exhibited the highest photocatalytic hydrogen formation rates under ultraviolet and visible irradiation (∼13,616 μmol H2·g–1·h–1). These ra...