Controlling oxide promoter coverage and microstructure on metals of inverse catalysts: Application to liquid phase tetrahydrofurfuryl alcohol conversion to 1,5-pentanediol

Abstract

Metal M1/metal oxide M2Ox (M1M2Ox) inverse catalysts, where the oxide layer rests atop metal, have gained attention for their distinct catalytic performance. They are intensively studied in biomass upgrading, e.g., the hydrogenolysis of tetrahydrofurfuryl alcohol to produce 1,5-pentanediol. Pt and MOx (M = W, Mo, Re, Nb) exhibit remarkable synergism in activity and selectivity, but the active sites remain poorly understood. Here, we examine the influence of oxide loading on PtMOx inverse catalysts and introduce a high-pressure wash treatment to leach the excess oxide from carbon and optimize their structure. The findings reveal a saturation sub-monolayer MOx coverage with 2D atomic structure on Pt that is crucial for performance; excessive loading leads to nanocrystalline of lower activity, and low loading exposes unselective metal sites. Wash treatment selectively removes MOx from carbon, enhances their dispersion on Pt, and improves, in most cases, the performance. Tuning the inverse structure advances structure-reactivity understanding.