Boosting the catalytic performance of graphene-supported Pt nanoparticles via decorating with –SnBun: an efficient approach for aqueous hydrogenation of biomass-derived compounds

Abstract

The pursuit of new catalysts for the aqueous transformation of biomass-derived compounds under mild conditions is an active area of research. In the present work, the selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-bishydroxymethylfuran (BHMF) was efficiently accomplished in water at 25 °C and 5 bar H₂ pressure (after 1 h full conversion and 100% selectivity). For this, a novel nanocatalyst based on graphene-supported Pt NPs decorated with Sn-butyl fragments (–SnBu_n) has been used. More specifically, Pt NPs supported on reduced graphene oxide (rGO) were functionalized with different equivalents (0.2, 0.5, 0.8 and 1 equiv.) of tributyltin hydride (Bu₃SnH) following a surface organometallic chemistry (SOMC) approach. The synthesized catalysts (Pt@rGO/Sn_x) were fully characterized by state-of-the-art techniques, confirming the presence of Sn-butyl fragments grafted on the platinum surface. The higher the amount of surface –SnBu_n, the higher the activity of the catalyst, reaching a maximum conversion with Pt@rGO/Sn_0.8. Indeed, the latter has proven to be one of the most active catalysts reported to date for the aqueous hydrogenation of HMF to BHMF (estimated TOF = 666.7 h⁻¹). Furthermore, Pt@rGO/Sn_0.8 has been demonstrated to be an efficient catalyst for the reduction of other biomass-derived compounds in water, such as furfural, vanillin or levoglucosenone. Here, the catalytic activity is remarkably boosted by Sn-butyl fragments located on the platinum surface, giving a catalyst several times faster than non-functionalized Pt@rGO.