Hierarchical Porous Nitrogen-Doped Carbon Catalyst by the Pickering HIPE Technique: Synthesis and Application in HMF Production

In this paper, water-in-oil (W/O)-type Pickering high-internal phase emulsions (Pickering HIPEs) were stabilized using the modified SBA-15 with appropriate wettability as the stable particle. After thermal polymerization and subsequent sulfonation, we obtained hierarchical porous nitrogen-doped carbon catalysts (SNCs) with acid–base bifunctional active sites. The as-prepared catalysts have hierarchical porous structures, and acidic and basic catalytic activity centers, which can significantly improve the catalytic activity of the conversion of glucose to 5-hydroxymethylfurfural (HMF). The results showed that the highest HMF yield of 61.3% can be obtained, and the recovered catalyst still has a significant catalytic activity after four consecutive cycles. This work offers a versatile strategy for developing nitrogen-doped carbonaceous catalysts for a wide range of biomass transformation to platform chemicals.