A review on the inference of doping TiO2 with metals/non-metals to improve its photocatalytic activities

Abstract

The band-gap energy of TiO2 nanoparticles has been modified using different methods. The study reviewed the effects of doping and co-doing TiO2 nanotubes with different metals and nonmetals to modify its band gap and improves the photocatalytic activity of the nanoparticles. From our findings reviewing different articles, co-doing TiO2 using dissimilar metal ions like Cerium (Ce) together with nitrogen (N) ions or chromium (Cr) and iron (Fe) ions will decrease particle size, broaden the area of the surface, and as well modifies the particle’s band-gap for visible light to energize an electron causing its movement from the valance band to the conduction band. The studies also revealed that co-doping TiO2 with chromium and iron metal ion demonstrated twice the photocatalytic activity for photodecomposition of gaseous-isopropyl alcohol when compared with single (Cr/Fe) doped TiO2 nanoparticles when exposed to visible light. The reviewed work estimated the optimal amount of Ce for Ce/N co-doped TiO2 at 0.05 grams. Different works of literature reviewed show that doping TiO2 with different transition metals reduces the band-gap for easy absorption of visible light and improvement in the photocatalytic activities of the nanoparticles.