Exploring the Influence of Carbonaceous Material on the Photocatalytic Performance of Composites Containing Bi-BiOBr and P25 TiO2 for NOx Remediation.

Abstract

Bi-BiOBr-P25 TiO2 composite exhibits high and synergistic improvements in the photocatalytic activity for nitrogen oxide (NOx) removal. Herein, we explored the influence of adding carbonaceous material to this composite, namely graphene (G), graphene oxide (GO), carbon nanotubes (CNT) and buckminsterfullerene (F); all at 1 wt.%. All samples were synthesised using a one-pot solvothermal method. The structural and morphological properties, composition, and photocatalytic performance of the composites and their parent materials were examined using scanning electron microscopy (SEM), carbon-hydrogen-nitrogen (CHN) elemental analysis, high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Raman spectroscopy, attenuated total reflectance Fourier transform infra-red (ATR-FTIR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, X-ray photoelectron spectroscopy (XPS), N2 sorption at 77 K, photoluminescence (PL) spectroscopy, diffuse reflectance transient absorption spectroscopy (DR-TAS) and photocatalytic testing against NOx gas in accordance with ISO protocol (22197-1:2016). Among the studied carbonaceous composites, the composite including GO showed the highest performance towards NOx remediation. For reactions in NO gas, it showed a combined higher NOx removal rate (21.9%) than its parent materials P25 (8.7%), Bi-BiOBr (6.5%) and GO (0%). For reactions in NO2 gas, it showed a higher NOx removal rate (~15%) than its parent materials P25 (~10%), Bi-BiOBr (~5%) and GO (0%).