Stabilizing cobalt catalysts for aqueous-phase reactions by strong metal-support interaction

J. Lee, S. Burt, C. Carrero, A. Alba-Rubio, I. Ro, J. O’Neil, H. Kim, D. Jackson, T. Kuech, I. Hermans, J. Dumesic, G. Huber  J. Catal. 330 (2015) 19


High-temperature calcination and reduction treatments of cobalt particles (17–20 nm) supported on TiO2 create cobalt particles covered with a TiOy layer. The layer thickness ranges from 2.8 to 4.0 nm. These phenomena, commonly called strong metal-support interaction (SMSI), can be used to improve the catalyst stability and change the catalyst selectivity. For example, non-overcoated cobalt catalysts leached during aqueous-phase hydrogenation (APH) of furfuryl alcohol, losing 44.6% of the cobalt after 35 h time-on-stream. In contrast, TiOy-overcoated cobalt catalysts did not lose any measurable cobalt by leaching and the cobalt particle size remained constant after 105 h time-on-stream. The 1,5-pentanediol selectivity from furfuryl alcohol hydrogenolysis increased with increasing TiOy layer thickness. The stabilized cobalt catalyst also had high yields for APH of xylose to xylitol (99%) and APH of furfural to furfuryl alcohol (95%). These results show that the SMSI effect produces a catalyst with a similar structure as catalysts prepared by atomic layer deposition, thereby opening up a cheaper and more industrially relevant method of stabilizing base-metal catalysts for aqueous-phase biomass conversion reactions. In addition, the SMSI effect can be used to tune catalyst selectivity, thus allowing the more precise atomic scale design of supported metal catalysts.

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