Yin, HangSun, ZhehaoLiu, KailiLi, ZhuofengChen, Yi LunLiu, RuhanLangley, JulienWibowo, Ary AnggaraJing, XuechenMacdonald, DanielJia, GuohuaCox, NicholasYin, Zongyou2025-12-162025-12-160002-7863PubMed:40947595WOS:001571668700001ORCID:/0000-0001-5792-7630/work/195263911ORCID:/0000-0002-7815-6115/work/195264686ORCID:/0000-0002-5631-4872/work/195265401https://hdl.handle.net/1885/733794937Photocatalytic α-C–H activation of alcohols to form aldehydes and ketones represents an important synthetic pathway, although the selective formation of C-centered radicals remains challenging due to competing O–H activation processes. While extensive research has explored heterojunction band alignment, charge transfer directionality, and component-specific redox reactions, the atomic structure at interfaces and its catalytic role have received limited attention. Here, we demonstrate a TiO2-CuO heterojunction photocatalyst that achieves exceptional selectivity in the oxidation of isopropanol to acetone, with a hydrogen production rate of approximately 4400 μmol/g/h. Through complementary characterization using X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and ab initio molecular dynamics (AIMD), we identify the formation of asymmetric Ti-O(H)-Cu+units at the TiO2/CuO heterojunction interface. In situ EPR reveals a ·C(OH)(CH3)2radical intermediate, confirming that the reaction proceeds via selective hydrogen atom transfer (HAT) of the α-C–H bond in isopropanol, in contrast to that of TiO2or CuO, which proceed via hydrogen extraction of the OH group. These mechanistic insights into interface-mediated catalysis provide new design principles for engineering atomic-scale catalytic interfaces, offering new opportunities for developing next-generation photocatalysts across diverse catalytic applications.The paper is adapted from H.Y.'s Ph.D. thesis. The authors acknowledge the financial support from the Australian Research Council (Grants FT230100059, DP240100687, IH220100012, LP210100436) and the support from Australian Microscopy and Microanalysis Research Facility at the Centre for Advanced Microscopy, the Australian National University. This research was undertaken with the assistance of resources provided by the National Computational Infrastructure (NCI) facilities at the Australian National University, which were allocated through the National Computational Merit Allocation Scheme (NCMAS), ANU Merit Allocation Scheme (ANUMAS).9en© 2025 American Chemical SocietyInsightsAnataseO-2Oxidation2025-09-1410.1021/jacs.4c17517105016865525