Peng, YongYongPengRuan, QingdongQingdongRuanLam, Chun HoChun HoLamMeng, FanxuFanxuMengCHUNG-YU GUANSantoso, Shella PermatasariShella PermatasariSantosoZou, XingliXingliZouYu, Edward T.Edward T.YuChu, Paul K.Paul K.ChuHsu, Hsien-YiHsien-YiHsu2024-10-012024-10-012021https://www.scopus.com/inward/record.uri?eid=2-s2.0-85102262492&doi=10.1016%2fj.jallcom.2021.159376&partnerID=40&md5=494cbbbceec20852488ad94b55655118https://scholars.lib.ntu.edu.tw/handle/123456789/721723Hematite (α-Fe2O3) is recognized as a promising photoelectrode material for photoelectrochemical (PEC) water splitting, as a result of its abundance, non-toxicity, suitable bandgap, and photochemical stability. Nevertheless, the undesirable physical and photophysical behaviors, such as poor conductivity, short diffusion length, and rapid charge-carrier recombination, seriously restrict PEC water splitting efficiency of hematite semiconductors. Herein, we fabricate nanoporous titanium (Ti)-doped α-Fe2O3 thin films by a facile hydrothermal reaction, subsequently utilizing energetic plasma ion implantation with a post-annealing process to significantly enhance the photoelectrochemical water oxidation performance of hematite. On the basis of materials characterization and electrochemical analysis, the optimized Ti-doped Fe2O3, i.e., Ti-4-Fe2O3, exhibits improved photocurrents of 0.55 and 1.07 mA cm−2 at 1.23 and 1.5 V versus RHE respectively under illumination of 100 mW/cm2 with AM 1.5 G spectrum, showing approximately 1.6-fold increases compared to pristine Fe2O3. We attribute this increase to improved charge carrier transport induced by Ti doping that reduces the recombination of light-driven charge carriers. The work utilizing plasma-assisted doping technique provides new insights into the surface engineering of photo-responsive semiconductors for the development of emerging hydrogen technologies. © 2021 Elsevier B.V.HematitePhotoelectrochemistryPlasma ion implantationSurface engineering[SDGs]SDG6journal article10.1016/j.jallcom.2021.1593762-s2.0-85102262492