Active composite photocatalyst synthesized from inactive Rh & Sb doped TiO₂ nanorods: Enhanced degradation of organic pollutants & antibacterial activity under visible light irradiation

In this study, rhodium-antimony co-doped TiO₂ nanorods and titanate nanotube (RS-TONR/TNT) composite was hydrothermally synthesized from rhodium-antimony co-doped TiO₂ nanorod (RS-TONR). Initially, RS-TONR and RS-TONR/TNT samples were photocatalytic inactive under visible light irradiation (λ≥420 nm). Catalytic performance of RS-TONR/TNT composite was improved by surface protonation and then post-calcination process. Calcination of protonated sample has transformed most titanate nanotubes of RS-TONR/TNT into anatase TiO₂ nanoparticle (TNP) in the composite. This composite contains admixture of both rutile phase of TiO₂ nanorods and TiO₂ nanoparticle (48/RS-TONR/TNP-400). The photocatalytic activity of 48/RS-TONR/TNP-400 composite was increased for decomposition of organic compounds under visible light irradiation. In the composite structure rutile phase of TiO₂ nanorods composed of rhodium-antimony co-doping is responsible for absorption of visible light irradiation and low band edge position of TNP facile the transport of conduction band charge carriers. At next step, 48/RS-TONR/TNP-400 sample was loaded with copper oxide as co-catalyst. The synergistic effect of calcination and co-catalyst was observed as Cu(3 wt%) 48/RS-TONR/TNP-400 sample showed the highest photocatalytic performance for degradation of organic pollutants. Also, Cu(3 wt%)-48/RS-TONR/TNP-400 photocatalyst was successfully applied for disinfection of both Gram-negative and Gram-positive bacterial pathogens such as E. coli, S. typhimurium and L. monocytogenes.