Hydrogenation of fatty acids to fatty alcohols over Ni3Fe nanoparticles anchored on TiO2 crystal catalyst: Metal support interaction and mechanism investigation

Catalytic transformation of fatty acids into fatty alcohols is the essential step to produce renewable energy and high-valuable chemicals from waste fatty acids. In this research, a series of Ni3Fe catalysts were synthesized to improve this transformation, specifically that the Ni3Fe anchored on TiO2 surface has performed excellent activity with a high alcohol yield reaching 91.2%. The structure–reactivity relationship between the Ni3Fe nanoparticles on different crystal types of TiO2 (anatase: A-TiO2, rutile: R-TiO2) was investigated. It was found that the as-prepared Ni3Fe/R-TiO2 catalyst showed better catalytic performance than that of Ni3Fe/A-TiO2. Both experimental and density functional theory (DFT) computational results indicated that the interactions between Ni3Fe nanoparticles and R-TiO2 support have highly promoted the formation of oxygen vacancy (Ov), which plays an essential role in CO and HH cleavage, thus promoting the hydrogenation towards fatty alcohols. Furthermore, the catalyst reusability tests showed that Ni3Fe/TiO2 catalyst exhibited good stability over four times recycled and excellent suitability for industrial crude fatty acid conversion.