11-P-07 - Formation of acidic hydroxyl groups during preparation of Pt/KL catalysts as studied by 1H MAS NMR

Abstract

Publisher Summary This chapter describes the formation of acidic hydroxyl groups during the preparation of Pt/KL catalysts as studied by 1 H magic angle spinning nuclear magnetic resonance (MAS-NMR). Acidic hydroxyl groups in Pt/KL zeolite prepared by the ion exchange method have been characterized quantitatively by 1 H MAS NMR. After the ion exchange by [Pt(NH 3 ) 4 ] 2+ , the calcination process produces acidic hydroxyl groups. NH 4 + ions produced by the decomposition of [Pt(NH 3 ) 4 ] 2+ are considered to be the origin. The H 2 reduction process also produces the acidic hydroxyl groups by the reaction Pt 2+ + H 2 → Pt 0 + 2H + . This indicates that after the calcination, Pt 2+ ions are dominant species. 1 H chemical shift depends on the concentrations of Pt, the acidic hydroxyl groups, and on the Pt state.