Investigation of catalytic performance regulation over Ag-, Mn-based catalysts in selective oxidation of 5-hydroxymethylfurfural

Abstract

Catalysis plays an important role in transforming biomass-derived molecules to value-added chemicals. This study investigates series of Ag-, Mn-, and AgMn-based catalysts, aiming to understand catalytic performances in selective oxidation of 5-hydroxymethylfurfural (HMF). The catalysts were characterized by XRD, TEM, Raman, FT-IR, and XPS to examine their crystal structures, size and shape, surface properties and chemical states. The catalytic results demonstrated that the Ag catalysts favored HMFCA production (Ag1.0/Co3O4, HMF conversion: 42.7%, HMFCA selectivity: 66.1%, DFF: negligible, FFCA: 11.6%), the Mn catalysts preferred DFF and cascade FFCA production (Mn1.0/Co₃O₄, HMF conversion: 38.2%, DFF: 22.8%, HMFCA: 7%, FFCA: 26.0%), and that the bimetallic AgMn catalysts exhibited a synergistic enhancement effect on product selectivity (Ag0.50Mn0.50/Co₃O₄, HMF conversion: 40.3%, DFF: 16.4%, HMFCA: 32.2%, FFCA selectivity: 51.5%). The results of FT-IR, XPS and the electrical conductivity tests revealed that the catalytic performances were related to the chemical states of Ag and Mn sites, the adsorption properties of catalyst surfaces, and the electron transfer mobility of catalysts. We anticipate that these research findings will spark peer interests in heterogeneous catalyst design.