Two series of hybrid inorganic–organic materials, prepared via interlayer organic modification of protonated Ruddlesden–Popper phases HLnTiO4
(Ln = La, Nd) with n-alkylamines and
n-alkoxy groups of various lengths, have been systematically studied with respect to photocatalytic
hydrogen evolution from aqueous methanol under near-ultraviolet irradiation for the first time.
Photocatalytic measurements were organized in such a way as to control a wide range of parameters,
including the hydrogen generation rate, quantum efficiency of the reaction, potential dark activity of
the sample, its actual volume concentration in the suspension, pH of the medium and stability of
the photocatalytic material under the operating conditions. The insertion of the organic modifiers
into the interlayer space of the titanates allowed obtaining new, more efficient photocatalytic materials, being up to 68 and 29 times superior in the activity in comparison with the initial unmodified
compounds HLnTiO4 and a reference photocatalyst TiO2 P25 Degussa, respectively. The hydrogen evolution rate over the samples correlates with the extent of their interlayer hydration, as in the
case of the inorganic–organic derivatives of other layered perovskites reported earlier. However, the
HLnTiO4
-based samples demonstrate increased stability with regard to the photodegradation of the
interlayer organic components as compared with related H2Ln2Ti3O10-based hybrid materials.