Modified Titania surfaces for visible light photo catalysis

Combining solar light with photocatalysts can destroy a variety of dangerous pollutants in air and water. It is potentially a very powerful method to clean up the contaminated environment. However, there are still many challenges concerning the efficiency and reliability of this approach. The advantage of visible light active materials as compared to UV light active materials is much more efficient energy utilization, as the solar spectrum contains only a small UV component. In this project we have developed various photocatalytic materials, more active than the conventional materials under both UV and visible light. We have investigated the fundamental and applied aspects of visible-light absorbing materials based on N-doped and B-doped TiO₂. The materials were very active in degradation of methyl terf-butyl ether (MTBE), a gasoline additive and a significant environmental contaminant. The B-doped photocatalysts had a maximum activity of photocatalysts occurring at 1.13 at.% B associated with an "active" boron component probably present substitutionally at oxygen sites (Figure 1). Inactive boron is also present as a boric oxide-like material¹. The N-doped photocatalysts had maximum activity occurring at 0.5 wt.% N². The visible light photoactivities of B and N co-doped materials were similar to those with the same level of B-only doping. In summary, effective visible light active photocatalysts have been prepared by a low-cost synthetic method that allows controllable and reproducible doping of TiO₂ with boron and nitrogen.