Heteroatom (N, S) Co-Doped CNTs in the Phenol Oxidation by Catalytic Wet Air Oxidation

The N, S-co-doping of commercial carbon nanotubes (CNTs) was performed by a solvent-free mechanothermal approach using thiourea. CNTs were mixed with the S-dual precursor in ball-milling apparatus, and further thermally treated under inert atmosphere between 600 1000 °C. influence temperature applied during thermal procedure investigated. Textural properties materials not significantly affected either mechanical step or heating phase. Concerning surface chemistry, developed methodology allowed incorporation N (up to 1.43%) S 1.3%), distributed pyridinic (N6), pyrrolic (N5), quaternary (NQ) groups, C–S–, C–S–O, sulphate functionalities. Catalytic activities S-doped evaluated for catalytic wet air oxidation (CWAO) phenol batch mode. Although samples revealed similar activity degradation, higher total organic removal (60%) observed sample at 900 improved this attributed presence N6, NQ, thiophenic groups. This tested continuous mode, around 30% conversion being achieved steady-state.