LASER RAMAN AND DTA/TGA STUDY OF H3+NPVNMO12-NO40 HETEROPOLYACIDS PURE AND SUPPORTED ON K3PMO12O40

According to TGA/DTA data thin layers of H3+nPV nMo12-nO40 heteropolyacids impregnated on K3PMo12O40 support display increased thermal stability. Raman spectroscopy proves that these deposited, catalytically significant, acid layers represent a new structural quality and tend to retain certain number of crystallization water molecules. It is argued that the acids become stabilized due to the epitaxial relationship with the support, and the isomorphous acid layers are tenatively described as hexahydrates of the respective acids. © 1990 J.C. Baltzer A.G. Scientific Publishing Company.