Photocatalysis assisted simultaneous carbon oxidation and NOx reduction

•The presence of oxygen shows improvement in carbon photo-oxidation with nitric oxide.•Carbon is selectively converted into CO2 while NOx is reduced to N2.•The formation of nitrate on TiO2 is proved to be in a dynamic process.•Uniform size reduction of the carbon particles in the presence of NO, O2 and H2O was observed with HR SEM, in spite of the distance to TiO2 photocatalytic particles.

Photocatalysis assisted oxidation of carbon black was performed using TiO2 photocatalyst under UV illumination in an atmosphere with NO, O2 and water vapor at 150 °C. Carbon is oxidized mainly to CO2 while NO is selectively converted to N2. Enhanced O2 and NO concentrations have a positive effect on the carbon oxidation rate. At a concentration of 3000 ppm NO and 13.3% O2 in the gas phase the carbon oxidation rate reaches 2.3 μgcarbon/mgTiO2 h, at a formal electron/photon quantum efficiency of 0.019. HR SEM images reveal uniform gradual reduction of the carbon particle size irrespective of the distance to TiO2 photocatalyst particles in the presence of NO, O2 and H2O.

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