%0 Journal Article %A Nandasiri, Manjula I. %A Shutthanandan, Vaithiyalingam %A Manandhar, Sandeep %A Schwarz, Ashleigh M. %A Oxenford, Lucas %A Kennedy, John V. %A Thevuthasan, Suntharampillai %A Henderson, Michael A. %D 2015 %T Instability of Hydrogenated TiO2 %U https://acs.figshare.com/articles/journal_contribution/Instability_of_Hydrogenated_TiO_sub_2_sub_/2005401 %R 10.1021/acs.jpclett.5b02219.s001 %2 https://acs.figshare.com/ndownloader/files/3011961 %K bulk diffusivity %K Hydrogenated TiO 2Hydrogenated TiO 2 %K Similar anneals %K photoelectron spectroscopy %K nm %K 473 K %K 373 K %K reaction analysis %K rutile %K light photocatalyst %K surface %K 523 K %K NRA %X Hydrogenated TiO2 (H-TiO2) is touted as a viable visible light photocatalyst. We report a systematic study on the thermal stability of H-implanted TiO2 using nuclear reaction analysis (NRA), Rutherford backscattering spectrometry, ultraviolet photoelectron spectroscopy, and X-ray photoelectron spectroscopy. Protons (40 keV) implanted at a ∼2 atom % level within a ∼120 nm wide profile of rutile TiO2(110) were situated ∼300 nm below the surface. NRA revealed that this H-profile broadened toward the surface after annealing at 373 K, dissipated out of the crystal into vacuum at 473 K, and was absent within the beam sampling depth (∼800 nm) at 523 K. Photoemission showed that the surface was reduced in concert with these changes. Similar anneals had no effect on pristine TiO2(110). The facile bulk diffusivity of H in rutile at low temperatures, as well as its interfacial activity toward reduction, significantly limits the utilization of H-TiO2 as a photocatalyst. %I ACS Publications