An investigation of the optical properties and water splitting potential of the coloured metallic perovskites Sr1−xBaxMoO3

•The solid solution Sr1-xBaxMoO3 has been synthesised.•A miscibility gap exists from x=0.1–1.0 in Sr1−xBaxMoO3.•Upon increasing x from 0 to 1 in Sr1−xBaxMoO3 there is a reduction in the measured band gap from 2.20 eV to 2.07 eV.•The potential of SrMoO3 and BaMoO3 as water-splitting photocatalysts was explored but there was no evidence of hydrogen or oxygen evolution, even with the presence of a Pt co-catalyst.

The solid solution Sr1−xBaxMoO3 (x=0.00, 0.025, 0.050, 0.075, 0.100 and 1.00) has been synthesised. Rietveld refinement of X-ray diffraction data shows that all materials crystallise with cubic (Pm-3m) symmetry and that a miscibility gap exists from x=0.1–1.0. The optical properties of the metallic perovskites Sr1−xBaxMoO3 have been investigated by a combination of UV–vis spectroscopy and density functional theory (DFT). Upon increasing x from 0 to 1 in Sr1−xBaxMoO3 there is a reduction in the measured band gap from 2.20 eV to 2.07 eV. The measured band gap is attributed to the electronic transition from the Mo 4d t2g band to the eg band. The potential of SrMoO3 and BaMoO3 as water-splitting photocatalysts was explored but there was no evidence of hydrogen or oxygen evolution, even with the presence of a Pt co-catalyst.

Graphical abstractUltraviolet–visible absorbance spectra (converted from diffuse reflectance spectra) for SrMoO3 and BaMoO3.Figure optionsDownload full-size imageDownload as PowerPoint slide