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

Abstract

a b s t r a c tHigh-temperature calcination and reduction treatments of cobalt particles (17-20 nm) supported on TiO 2 create cobalt particles covered with a TiO y 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, TiO y -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 TiO y 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.

Insights on the One‐Pot Formation of 1,5‐Pentanediol from Furfural with Co−Al Spinel‐based Nanoparticles as an Alternative to Noble Metal Catalysts

“…For instance, Wu et. [16] However, to the best of our knowledge there is no report of the one step production of diols from FA over non-noble metalcontaining catalysts. reported FA hydrogenation to form either FFA or THFA, over bimetallic CuNi nanoparticles (NPs) supported on Mg/Al oxides.…”

“…successfully applied a Co supported on TiO 2 catalyst for continuous flow FFA hydrogenation in aqueous media, producing 30 % of 1,5-PeD. [16] However, to the best of our knowledge there is no report of the one step production of diols from FA over non-noble metalcontaining catalysts. In this regard, here, it is presented the activation and catalytic behaviour of CoÀ Al spinel NPs synthesized by flame spray pyrolysis (FSP) in the one step one pot reduction of FA to PeDs.…”

Controlled deposition of titanium oxide overcoats by non-hydrolytic sol gel for improved catalyst selectivity and stability

“…Tilley and coworkers developed a thermolytic molecular approach, which allowed the generation of multicomponent oxides such as Ti-Si [24] as well as various surface modifications [25], but deposition was limited to one molecular layer [26]. In addition to overcoating strategies, high-temperature calcination and reduction were also employed to cover Co particles with a titanium oxide layer, leading to improvements in catalyst stability and changes in selectivity thanks to strong metal-support interaction during aqueous-phase hydrogenation of furfuryl alcohol [27].…”

In Situ Local Temperature Mapping in Microscopy Nano‐Reactors with Luminescence Thermometry

“…[13,14] The potential of this versatile reaction has resulted in extensive research using traditional spectroscopic techniques, e. g. Raman, UV-Vis and FT-IR spectroscopy. [15][16][17] These techniques provide valuable insight on the organic part of the catalytic reaction (e. g. products and intermediates). However, information on the inorganic materials (e. g. catalyst and support) is also vital for the complete understanding of structure-performance relations in catalysis.…”