Effect of Pt Particle Size and Phosphorous Addition on Furfural Hydrogenation Over Pt/Al2O3

Abstract

Pt/Al2O3 catalysts with different Pt particle sizes and after phosphorous deposition were studied for liquid phase catalysed furfural hydrogenation. The activity and selectivity were related to various physico-chemical properties studied by scanning transmission electron microscopy, N2 physisorption, 31P nuclear magnetic resonance, diffuse reflectance Fourier transform infrared spectroscopy and attenuated total reflectance infrared spectroscopy. The results indicate that the large particles obtained upon calcination of 1 wt% Pt/Al2O3 at 600 °C exhibited higher turnover frequency per surface Pt; nonetheless, the overall activity decreased due to the loss of surface Pt upon sintering. While in certain cases phosphorous can act as promoter, the addition of this element to Pt/Al2O3 resulted in catalyst poisoning, which was ascribed to Pt encapsulation/blockage effects related to formation of AlPO4. Finally, gradual deactivation of Pt/Al2O3 was observed over five consecutive catalytic cycles which was caused by Pt sintering (from 0.6 to 2.0 nm) as well as by irreversible adsorption of organic reaction intermediates. Graphic Abstract: [Figure not available: see fulltext.]