arXiv subjects

Umamaheswari Venkatesan

Publications and source records attributed to Umamaheswari Venkatesan.

2 recordsLinked to original sources

arXiv2016

Black TiO2 nanotubes formed by high energy proton implantation show noble-metal-co-catalyst free photocatalytic H2-evolution

We apply high-energy proton ion-implantation to modify TiO2 nanotubes selectively at their tops. In the proton-implanted region we observe the creation of intrinsic co-catalytic centers for photocatalytic H2-evolution. We find proton implantation to induce specific defects and a characteristic modification of the electronic properties not only in nanotubes but also on anatase single crystal (001) surfaces. Nevertheless, for TiO2 nanotubes a strong synergetic effect between implanted region (catalyst) and implant-free tube segment (absorber) can be obtained.

physics.chem-ph↗

arXiv2016

Hydrogenated anatase: Strong photocatalytic H2 evolution without the use of a co-catalyst

In the present work we show, how a high pressure hydrogenation of commercial anatase or anatase/rutile powder can create a photocatalyst for hydrogen evolution that is highly effective and stable without the need of any additional co-catalyst. This activation effect can not be observed for rutile. For anatase/rutile mixtures, however, a strong synergistic effect is found (similar to findings commonly observed for noble metal decorated TiO2). ESR measurements indicate the intrinsic co-catalytic activation of anatase TiO2 to be due to specific defect centers formed during hydrogenation.

physics.chem-ph↗