La2O2CO3-Supported Ni Nanoparticles with Enhanced Metal–Support Interactions for Selective Hydrogenation

Electronic metal–support interactions (EMSIs) of supported metal nanoparticle (NP) catalysts have significant impacts on catalytic performances. In this work, phase transition from the monoclinic phase with La–O6 bonds to the hexagonal phase with La–O8 bonds of La2O2CO3 is induced by the presence of Ni, and the process of phase transition is characterized by XRD. The resulting La2O2CO3-supported Ni NP catalyst shows an improved EMSI in comparison to the Ni/La2O2CO3 catalyst prepared by a simple impregnation method. The enhanced EMSI effects are revealed by extensive characterizations such as XPS, H2-TPR, and H2-TPD. The EMSI effects create more Niδ+–O–La interfaces that are responsible for the enhanced reaction activity toward biomass upgrading of selective hydrogenation of levulinic acid to γ-valerolactone. This work provides insight into the use of phase transition to strengthen EMSI effects.