The acidity and catalytic activity of heteropoly acid on MCM-41 investigated by MAS NMR, FTIR and catalytic tests Original Research Article

The potential of supported heteropoly acids (HPAs) is of great significance in acid catalysis. In this contribution, the HPA H3PW12O40 (PW) was impregnated into SiMCM-41 and the resulting PW/SiMCM-41 acidic system was investigated by means of spectroscopy (MAS NMR, FTIR) and catalytic testing. The complexation of PW with the SiMCM-41 hydroxyls is purported to enhance the acidity and catalytic activity of these silanols. The effect of PW loading on structure, acidity and catalytic performance is monitored. The host material suffers severe structural distortions at higher loadings which lead to a considerable loss in the structural order. Based on these experimental findings, both acidity and catalytic performance were optimal with a loading of around 23 wt.% PW.