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 ac-tivity with a high alcohol yield reaching 91.2%. The structure-reactivity relationship between the Ni3Fe nano -particles 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 C-O and H-H 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.