Hydrogen bonding assisted formation of sandwich-type titanium-containing heteropolymolybdates: water-soluble and photoelectroactive

Abstract

Titanium-substituted polyoxometalates related with the semiconductor TiO₂ have potential applications in photocatalytic, photovoltaic and semiconducting materials. In this work, we synthesize two water-soluble titanium-containing polyoxomolybdates (NH₄)₈[(CH₃)₄N]₂[Ti₂(SbMo₇O₂₇)₂]·15H₂O (1) and (NH₄)₁₀[Ti₂(AsMo₇O₂₇)₂]·16H₂O (2) by a conventional aqueous solution method. Ammonia water as a starting material could play dual roles of a pH adjustor and a hydrogen bond assistant, resulting in the formation of many strong hydrogen bonds in their crystal structures. The electrochemical properties of compounds 1 and 2 were investigated by cyclic voltammogram measurements, and the diffuse reflectance UV-vis spectra of 1 and 2 were recorded to calculate their semiconductor band gap (E_g) values. Furthermore, using the two compounds as semiconducting materials, we carried out the photoelectrochemical sensing of bisphenol A in aqueous solution, indicating that bisphenol A in aqueous solution could be detected by means of photocurrent change.