Contribution of SmPO4 on raising electron-enriched nickel for efficient and complete hydrogenation of furfural and mimic substrates

The rational modulation of the electronic state via interaction of components is pivotal for optimizing the performance of solid materials in particular for heterogeneous catalysts. Unlike the electron-withdrawing effect of popular supports, herein, it is discovered that a unique electron modulation effect of SmPO 4 (a rare earth phosphate) on nickel (Ni) nanoparticles (10 wt%) supported on AlPO 4 -SmPO 4 composite carrier, enables efficient hydrogenation of furfural (FAL) to tetrahydrofurfuryl alcohol (THFA) under mild conditions (423 K, 1.0 MPa H 2 ). In comparison to the influence of AlPO 4 , comprehensive characterizations (X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and H 2 temperature-programmed reduction (H 2 -TPR)) confirm that SmPO 4 can act as an efficient electron donor, transferring electron to Ni along the AlPO 4 -SmPO 4 interface and forming electron-enriched Ni active sites. This electron-enriched state, coupled with the interface structure of the composite support, constructs a double-site activation system: electron-enriched Ni sites on AlPO 4 -SmPO 4 interface synergistically activate the conjugated C=O and C=C bonds, facilitating efficient and selective complete hydrogenation of FAL. The Ni/AlPO 4 -SmPO 4 catalyst with the optimized Al:Sm ratio exhibits exceptional catalytic performance with a FAL conversion of 99.2% and a THFA selectivity of 94.0%, outperforming most reported Ni-based catalysts under milder conditions. Additionally, the catalyst demonstrates attractive stability and broad applicability for a scope of cyclic unsaturated substrates like FAL. This work highlights the unique electron modulation function of rare earth phosphates in tailoring metal electronic states, and provides a promising strategy for designing high-performance non-noble metal materials for corresponding technically important chemical engineering processes.