Tailored Brønsted and Lewis surface acid sites of the phosphotungstic Wells Dawson heteropoly-acid

The synthesis of transition metals Wells Dawson heteropoly salts along with their elemental composition, water content, structure and specific surface area were thoroughly investigated. Additionally, the use of a molecular probe such as pyridine allowed the quantification of Lewis and Brønsted surface acid sites. The transition metals counter-cations provide both Lewis and Brønsted acid sites. The concentration of Brønsted acid sites is influenced by the crystallization water associated with the heteropoly anion.