A Nitrogen and Phosphorus Co‐Doped Carbon Material for Catalytic Oxidation of Furfural to Maleic Acid: Kinetics and Mechanical Pathway

ABSTRACT A nitrogen and phosphorus co‐doped carbon material (NPC‐5) was successfully prepared. This material exhibited a high specific surface area, abundant defect structures, and a high density of active sites, which contributed to its excellent catalytic performance on the catalytic oxidation of furfural to maleic acid. At 80°C for 7 h, NPC‐5 achieved a 85.7% of maleic acid yield. Combined characterization analyses and experimental results revealed that the synergistic effect of nitrogen and phosphorus co‐doping significantly enhanced the catalytic activity of NPC‐5. This synergistic effect primarily functioned by promoting the decomposition of H 2 O 2 to generate hydroxyl radicals (•OH), which further drove the selective oxidation of furfural to maleic acid. Notably, NPC‐5 also demonstrated excellent stability. After six consecutive catalytic cycles, it still retained 81.9% of the maleic acid yield. Experimental and kinetic studies confirmed that NPC‐5 catalyzed the oxidation of furfural to maleic acid through three distinct reaction pathways. The ·OH‐mediated Pathway I dominated the entire furfural conversion process. The mechanism involved ·OH abstracting a hydrogen atom from furfural to form a furfural radical, which undergoes hydration, 1,4‐rearrangement, hydrolysis, and decarboxylation to form β ‐formylacrylic acid ( β ‐FA). β ‐FA was directly oxidized to maleic acid or isomerized to 5‐hydroxy‐furan‐2(5H)‐one (HFONE) before further oxidation.