Synthesis of (H3O)TiNbO5·0.26H2O ia hydronium (H3O+) ion-exchange reaction and its photocatalytic activity forH2 evolution from aqueous methanol solution

Abstract

(H₃O)TiNbO₅·0.26H₂O powder was prepared from layered titanoniobate, KTiNbO₅, using an ion-exchange reaction in acidic aqueous solution. X-ray diffraction, thermogravimetry–differential thermal analysis, energy-dispersive X-ray analysis and infrared spectral data gave the first experimental evidence that the so-called proton-exchanged form HTiNbO₅ involves hydrated water or hydrated hydronium ion. The intercalation of water or hydronium ion in KTiNbO₅ was not achieved by the conventional high-temperature solid-state reaction method but by the low-temperature polymerizable complex (PC) method. While KTiNbO₅ia the PC route, combined with Pt, showed only little improvement of the photocatalytic activity with respect to H₂ evolution from aqueous methanol solution, the water or hydronium ion intercalated species, (H₃O)TiNbO₅·0.26H₂O, with Pt loading, showed much higher activities than the others species studied by an order of magnitude.