A Highly Efficient TiO_2–xC_x Nano-heterojunction Photocatalyst for Visible Light Induced Antibacterial Applications

Abstract

Visible-light-induced antibacterial activity of carbon-doped anatase-brookite titania nano-heterojunction photocatalysts are reported for the first time. These heterostructures were prepared using a novel low temperature (100 °C) non-hydrothermal low power microwave (300 W) assisted method. Formation of interband C 2p states was found to be responsible for the band gap narrowing of the carbon doped heterojunctions. The most active photocatalyst obtained after 60 minutes of microwave irradiation respectively. It is proposed that the photo-excited electrons (from the C 2p level) are effectively transferred from the conduction band of brookite to that of anatase causing efficient electron-hole separation, which is found to be responsible for the superior visible-light induced photocatalytic and antibacterial activities of carbon-doped anatase-brookite nano-heterojunctions.

Antibacterial properties of F-doped ZnO visible light photocatalyst

“…The Si and F modified coatings reduced the bacterial adhesion by 68% at 12 h compared with stainless steel [46]. A number of doped/co-doped photocatalytic materials were also reported [42,[47][48][49][50][51][52][53][54] to show antibacterial action. However, a direct comparison of the efficiency of these catalysts is not possible due to the lack of a standard testing protocol.…”

A review of solar and visible light active TiO2 photocatalysis for treating bacteria, cyanotoxins and contaminants of emerging concern

“…It was also suggested that despite the decrease in band gap energy, metals were not always successfully introduced into the TiO 2 framework, and that the remaining metals on the outside surface sheltered the photoreaction sites [44]. Significant attention has been directed at reducing the band gap and in turn increasing the visible light activity of TiO 2 by doping with a range of non-metal elements including nitrogen [34,[45][46][47][48][49], carbon [43,[50][51][52][53], sulphur [54][55][56], phosphorous [57], boron [58,59], oxygen [60], and fluorine [61,62], along with heterojunctions [63][64][65][66][67] and combinations of these elements [68][69][70][71][72][73].…”

Supported TiO2 films deposited at different energies: Implications of the surface compactness on the catalytic kinetics.

“…TiO 2 composites with added bactericide metal/oxides deposited by colloids calcined on heat resistant surfaces has been the subject of many recent studies [1,2]. The effect of TiO 2 -N,S nanoparticles and sputtered TiO 2 films to increase visible light absorption and accelerate bacterial inactivation kinetics have been recently reviewed by Dionysiou et al, [3,4], Foster et al, [5], Pillai et al, [6][7][8], Byrne et al, [9], Navabpour et al, [10], Verran et al, [11] and Bahnemann et al, [12,13]. Since the uniform and reproducible adhesion of TiO 2 films on substrates starting form colloidal depositions has been shown to present serious problems, antibacterial TiO 2 and TiO 2 -composites have been recently prepared by chemical vapor deposition (CVD), by RF-sputtering and evaluated in regards to their bactericide features [14][15][16].…”