Three folders of raw data for series of fresh CsxH3-xPW12O40 catalysts (where x = 0, 1, 1.5, 2, 2.5, 3) and used Cs1.5H1.5PW12O40 catalysts open readable .txt format. Datasets for PXRD, FTIR, Pyridine FTIR, and NH3-TPD. Organised into three folders = PXRD, FTIR, and acid site characterisation. 

PXRD collected using a Panalytical X’Pert Pro diffractometer with a Co source (λ = 1.7890 Å). Pawley fitting of the catalysts was carried out using TOPAS Academic V5 to determine lattice parameters, with Pseudo-Voight peak types and modelling of background and instrument parameters.

Temperature-programmed desorption (TPD) measurements using ammonia probe molecules for analysis of acid sites were conducted using a Micromeritics Autochem 2920 II equipped with a thermal conductivity detector (TCD). 

Fourier transform infrared (FTIR) spectra of the catalysts were recorded using a PerkinElmer IR spectrometer employing the attenuated total reflectance (ATR) method. To determine the nature of the acid sites (Brønsted and Lewis) on the catalyst surface, pyridine adsorption FT-IR measurements were performed.