The objective of this study was synthesis, characterization, and catalytic testing of mono-cationic (GaPW12O40, AlPW12O40) and bi-cationic (CsGa0.5H0.5PW12O40, CSAl0.5H0.5PW12O40) salts of tungstophosphoric acid. These heteropoly salts are characterized by Bronsted acidity derived from protons generated by dissociation of water molecules coordinated to the metal atoms. Catalytic activity of the studied salts was evaluated based on ethanol conversion and compared with the well-known parent heteropolyacid H3PW12O40. The reaction products, ethylene and diethyl ether, were monitored simultaneously by FTIR spectroscopy and chromatographic analysis. The infrared studies indicated that ethylene is formed not only from ethanol but also by diethyl ether decomposition. Cs-doped bi-cationic catalysts exhibited higher activity for ethylene and ether formation than the mono-cationic salts. The following order of catalytic activity was established: H3PW12O40 > CsGa0.5H0.5PW12O40 similar to CsAl0.5H0.5PW12O40 > GaPW12O40 >AlPW12O40. It is in agreement with the order of their acid strength determined by microcalorimetry and specific surface areas of the studied catalysts. (C) 2015 Elsevier B.V. All rights reserved.