Khan, Sovann Je, Minyeong Kim, Donghun Lee, Seungwoo Cho, So-Hye Song, Taeseup Choi, Heechae 2024-01-19T17:32:32Z 2024-01-19T17:32:32Z 2021-09-05 2020-05-14 1932-7447 https://pubs.kist.re.kr/handle/201004/118621 Brookite, the least studied crystalline phase of TiO2 recently has been found to have excellent photocatalytic activities, comparable to that of anatase TiO2. However, its activity is highly dependent on its defect levels. We systematically studied the equilibria of the native point defects of brookite, along with their effects on photocatalytic activities. From first-principles calculations and thermodynamics modeling, we predicted the formation of an interstitial defect (Ti-i(4+)) under weak reductive conditions while that of Ti-O(4+) under strong reductive conditions. Our calculations also suggest that Ti-i(4+) exclusively induces ideal shallow defect levels in brookite, but Ti-O(4+) results in deep level formations. In our experiments, we demonstrated that the moderately reduced brookite TiO2 sample has the best photocatalytic activity. This combined theoretical and experimental work explains the inconsistent photocatalytic activities of brookite and suggests the processing conditions that yield highly active brookite photocatalysts-one that is comparable to or exceeding that of anatase. English American Chemical Society GENERALIZED GRADIENT APPROXIMATION SELF-DOPED TIO2 COMPUTATIONAL PREDICTIONS RUTILE TRANSFORMATION ABSORPTION REDUCTION HYDROGEN ENERGY OXIDE Mapping Point Defects of Brookite TiO2 for Photocatalytic Activity Beyond Anatase and P25 Article 10.1021/acs.jpcc.0c02091 1 The Journal of Physical Chemistry C, v.124, no.19, pp.10376 - 10384 The Journal of Physical Chemistry C 124 19 10376 10384 scie scopus 000535281300014 2-s2.0-85087975779 Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science Article GENERALIZED GRADIENT APPROXIMATION SELF-DOPED TIO2 COMPUTATIONAL PREDICTIONS RUTILE TRANSFORMATION ABSORPTION REDUCTION HYDROGEN ENERGY OXIDE photocatalysis brookite TiO2 defect DFT hydrogen evolution