Carbon-coated nickel phosphide with enriched surface Niδ + sites enables an exceptionally high productivity of 2-methylfuran from biomass upgrading†

Abstract

In this study, we successfully synthesized a carbon-coated nickel phosphide composite catalyst (Ni₂P@C) through a strategy of polyvinylpyrrolidone (PVP)-assisted pyrolysis and phosphidation of Ni-MOF. Thorough structural characterization revealed that the assistance of PVP significantly decreased the size of the nickel nanoparticles during pyrolysis, and the subsequent gas phosphidation transformed the metallic nickel into the Ni₂P phase with strengthened Ni–P synergy. The resulting core–shell structured Ni₂P@C possessed a substantial number of surface Ni^{δ +} sites with electron deficiency, which served as both a metal center to dissociate hydrogen and a Lewis acid to activate the C–O bond. Remarkably, under mild reaction conditions (120 °C and p_{H 2} of 2.0 MPa), the Ni₂P@C composite demonstrated exceptional activity for hydrodeoxygenation of furfuryl alcohol, achieving an impressive 2-methylfuran productivity of 1.7 g_2-MF g_Cata⁻¹ h⁻¹. These results surpass the performance of most non-noble metal catalysts currently reported. This study could provide valuable insights for the rational design of advanced carbon-coated Ni₂P composite catalysts for hydrogenative biomass upgrading.