The calcination temperature (400–600 °C) of NiO was modulated and then the support effect on a Pt-supported catalyst was studied for the base-free aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid. Various characterizations revealed that NiO calcined at 400 °C showed a mesoporous structure, a largest specific area (89 m2 g−1), abundant reactive oxygen species (55.1 mmol g−1). Therefore, the corresponding Pt/Ni400c catalyst enabled 100% selectivity of FDCA at 100% conversion of HMF in water under 10 bar of O2, 100 °C and 12 h. The role of different oxygen species in NiO for transforming HMF and the intermediates was elucidated.