Layered Dion-Jacobson phases RbLaNb2O7, 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 to yield AgLaNb2O7 and Ag2La2Ti3O10. The silver-exchanged RbA2Nb3O10 layered structures yielded a mixture of AgNbO3 and an unidentified phase. Incorporation of silver cations into the interlayer spacing of the perovskite structures has shown to decrease optical bandgap sizes, increase surface areas, and extend the light absorption into the visible region. Significant increases in photocatalytic hydrogen production rates for all silver exchanged products have been observed. The highest observed photocatalytic rate for hydrogen formation under visible-light irradiation was for Ag2La2Ti3O10 (40 �mol H2�g-1�h-1). The silver-exchanged RbA2Nb3O10 layered structures exhibited the highest photocatalytic hydrogen formation rates measured in aqueous methanol under ultraviolet and visible irradiation (13,616 �mol H2�g-1�h-1). These rates were ten times higher than before silver exchange (1,418 �mol H2�g-1�h-1).

Silver-exchange of layered metal oxides and their photocatalytic activities

246th National Meeting (2013)

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