Carbon coated Ni/Al2O3 as high-efficiency catalysts for hydrogenation of furfural to furfuryl alcohol

Abstract

In this work, the catalytic hydrogenation process of furfural to furfuryl alcohol was evaluated over newly designed (Ni/Al₂O₃)@C catalysts. Using Ni2Al layered double hydroxide (Ni2Al-LDH) as the precursor, NiO/Al2O3 was obtained via hightemperature calcination. Glucose was used as the carbon source. The (Ni/Al₂O₃)@C catalysts were fabricated through hydrothermal and calcination under a N2 atmosphere with the different mass ratio of glucose to NiO/Al2O3. Several characterizations including XRD, TGA, SEM, BET, TEM, HRTEM and XPS were performed to characterize the microstructural features and chemical constituents of the prepared catalysts. It was found that the size of Ni nanoparticle size of Ni/Al2O3 was 7.2 nm and that of the carbon coated Ni/Al2O3 catalysts was smaller. It was indicated that modification with carbon coating could effectively enhance the dispersibility of Ni active components and inhibit them from oxidization. In addition, the performance of the carbon coated Ni/Al2O3 catalysts was affected by reaction solvent, the carbon content and calcination temperature. Under the optimal conditions, furfural conversion and furfuryl alcohol selectivity reached 96.4% and 89.4% over (Ni/Al₂O₃)@C-2-500 catalyst, respectively. The (Ni/Al₂O₃)@C-2-500 catalyst proved to be reusable during multiple recycling runs. The high catalytic performance of (Ni/Al₂O₃)@C-2-500 may be due to the smaller Ni nanoparticles, larger specific surface area, more surface oxygen vacancies and enriched Ni 0 .