Selective and effective oxidation of 5-hydroxymethylfurfural by tuning the intermediates adsorption on Co-Cu-CN_x

Co-based catalysts are promising alternatives to precious metals for the selective and effective oxidation of 5-hydroxymethylfurfural (HMF) to the higher value-added 2,5-furandicarboxylic acid (FDCA). However, these catalysts still suffer from unsatisfactory activity and poor selectivity. A series of N-doped carbon-supported Co-based dual-metal nanoparticles (NPs) have been designed, among which the Co-Cu_1.4-CN_x exhibits enhanced HMF oxidative activity, achieving FDCA formation rates 4 times higher than that of pristine Co-CN_x, with 100% FDCA selectivity. Density functional theory (DFT) calculations evidenced that the increased electron density on Co sites induced by Cu can mediate the positive electronegativity offset to downshift the d-band center of Co-Cu_1.4-CN_x, thus reducing the energy barriers for the conversion of HMF to FDCA. Such findings will support the development of superior non-precious metal catalysts for HMF oxidation.