Titanium oxide/nickel foam (TiO2/NF) catalyzed the conversion of glucose to 5-hydroxymethylfurfural in subcritical solvothermal liquefaction

Abstract

The glucose conversion into 5-hydroxymethylfurfural (HMF) typically required Lewis and Brønsted acid catalysts. The mesoporous TiO2 supported on nickel foam (NF) was synthesized using modified sol–gel dip-coating methods. The prepared catalysts were characterized to observe their physical and physicochemical properties. The catalyst characterization showed that TiO2 is successfully incorporated onto the NF surface. Nitrogen adsorption/desorption isotherms and NH3-TPD analysis showed that the TiO2/NF catalysts have a large specific surface area and high surface acidity, which can enhance glucose dehydration. The liquid products from the solvothermal reaction were analyzed using GC–MS analysis. Under the optimal reaction conditions, about 46% of HMF yield was obtained, and the liquid products contained furan derivatives and phenolic compounds. The solid TiO2/NF catalyst allowed easy catalyst recovery from liquid products. The reusability of the TiO2/NF catalysts is still acceptable and shows the TiO2/NF catalyst's potential for usage in HMF production.