Enhancement of formaldehyde removal by graphene, S, and N doping on TiO₂ nanocomposite photocatalyst

The photocatalysis process for volatile organic compounds (VOCs) such as formaldehyde is considered a potential strategy due to its high efficiency and low cost. In this study, TiO₂ was co-modified by the addition of sulfur (S), nitrogen (N), and reduced graphene oxide (rGO) under a solvothermal method for its enhancement on formaldehyde degradation. Characterization analysis of the modified TiO₂ displayed an average particle size of 9.37 nm and was totally composed of anatase phase. The photocatalyst of 0.1rGO/S_0·05N_0·1TiO₂ performed efficient visible-light-driven photocatalytic activity of formaldehyde conversion under the range of 10–60% relative humidity due to lower water adsorption competition and pores blocking. The addition of rGO, S, and N increased specific surface area, light absorption, bonding of oxygen-containing functional groups, and electron transfer capacity which are critical factors in photocatalysis activity.