Screening tests for the evaluation of nanoparticle titania photocatalysts

Abstract

AbstractBACKGROUND: Nano‐sized titanium dioxide has potential as a photocatalyst, and doped variants may have different photocatalytic properties. Nano‐titanias with a wide range of dopants and compositions can be prepared using continuous hydrothermal flow synthesis (CHFS), but when many samples are made, a large‐scale screening test is required to investigate their properties. A range of doped nano‐titanias were prepared using a CHFS route, and investigated as powders using a range of photocatalytic test methods. These tests included decolourization of methylene blue (in the presence of oxygen), partial oxidation of a simple alcohol (propan‐2‐ol) and the degradation of aqueous solutions of dichloroacetic acid. The practicality of the tests for large‐scale screening was considered, and the test results were cross‐correlated to see if any of them gave similar ranking for activity of the photocatalysts.RESULTS: Two of the tests, namely DCA degradation and propan‐2‐ol, gave similar rank ordering for the nanopowders, while the MB decolourization results did not suggest a strong correlation with any other test. The addition of metal dopants was observed to produce varying results between different dopants and tests.CONCLUSIONS: Two of the tests, DCA degradation and MB decolourization in visible light, were recommended for further use as screening tests. Copyright © 2009 Society of Chemical Industry