Mo@Pt overlayers as efficient catalysts for hydrodeoxygenation of guaiacol and anisole

Abstract

Silica alumina supported Mo@Pt overlayer catalysts were prepared via the directed deposition technique and evaluated for hydrodeoxygenation (HDO) of guaiacol and anisole. As predicted computationally, Mo@Pt overlayers showed reduced heats of hydrogen and carbon monoxide adsorption via chemisorption. The decreased activity of Mo@Pt overlayer catalysts for the ethylene hydrogenation descriptor reaction also suggested decreased hydrogen adsorption strength compared to a Pt only catalyst. H₂-TPR results demonstrated the close interaction between Pt and Mo species for Mo@Pt overlayer catalysts and the enhanced reducibility of the molybdenum oxides via deposition of Pt to Mo. Mo@Pt overlayer catalysts showed significantly improved guaiacol and anisole hydrodeoxygenation (HDO) activity compared to the monometallic Pt and Mo catalysts. For the guaiacol HDO reaction at 350 °C, the Mo@Pt double deposition (DD) showed the highest HDO turnover frequency (TOF), twice as high as that of Pt and Mo catalysts. For the Mo@Pt DD catalyst, the selectivity to benzene, toluene, and xylenes (BTX) could reach up to 80% for HDO of guaiacol and anisole at high contact time compared to 43% for HDO of anisole over the Pt catalyst.