Photocatalytic oxidation of nitric oxide over AgNPs/TiO₂-loaded carbon fiber cloths

Series of AgNPs/TiO₂-loaded carbon fiber cloth (CFC) composites were prepared by incorporation of pristine TiO₂ and three AgNPs-modified TiO₂ additives onto the surface of four commercial CFCs. AgNPs/TiO₂ photocatalysts were synthesized by the wet impregnation method, including NaBH₄ reduction of silver ions. The silver content in the modified photocatalyst was assessed by inductively coupled plasma optical emission spectrometry (ICP-OES) as well as XRD analysis. It can be indicated that silver was successfully reduced to Ag nanoparticles what was confirmed by UV-Vis/DRS as well as XRD methods. The photocatalytic activity of the AgNPs/TiO₂-loaded CFCs was evaluated during the photocatalytic oxidation (PCO) tests of nitric oxide (NO) acting as a model air contaminant under UV light. It was found that the highest NO removal rate was observed for the AgNPs/TiO₂-loaded CFC material containing 3.70 wt% of AgNPs. Modification of TiO₂ with AgNPs stabilized the photocatalytic efficiency of the composites during 5 as well as 24 consecutive NO photooxidation cycles. It was also concluded that the presence of AgNPs was a key factor responsible for hindering NO₂ formation.