Pt–Carbon interaction-determined reaction pathway and selectivity for hydrogenation of 5-hydroxymethylfurfural over carbon supported Pt catalysts

Abstract

In this study, a series of Pt catalysts supported on carbon materials, including multi-walled carbon nanotubes (CNTs), reduced graphene oxide (rGO), graphitic carbon nitride (g-C₃N₄), and biochar (BC), were prepared by impregnation or atomic layer deposition (ALD) methods. The Pt content was around 2.5 wt% in all the Pt catalysts, and the average Pt particle size was 1.6–1.9 nm for the catalysts prepared by impregnation (IM), which was slightly larger than that for the Pt catalyst (∼1.4 nm) synthesized by ALD (Pt/CNTs-ALD). All the catalysts were used in the HMF hydrogenation reaction to investigate the effects of different carbon materials and Pt–carbon interactions on the catalytic performance of catalysts. The main product was DHMF over all the Pt catalysts prepared by impregnation, and Pt/BC-IM showed the highest turnover frequency and the highest selectivity to DHMF (95.3%) with an HMF conversion of 94.6% after 10 h of reaction time, which could be due to the abundant functional groups on the surface of BC. Compared with the Pt/CNTs-IM catalyst, the main product over the Pt/CNTs-ALD catalyst was DMF with a yield of 47% due to the relatively strong Pt–CNT interaction. The interaction between Pt and CNTs is the dominant factor in determining the main product in the selective HMF hydrogenation reaction. After introducing Ni nanoparticles to Pt/CNTs-ALD, the yield of DMF reached 93.4% over the PtNi/CNTs-ALD bimetallic catalyst owing to the synergistic effect between Pt and Ni.