Hsueh, Jing-WenJing-WenHsuehKuo, Lai-HsiangLai-HsiangKuoChen, Wan-HsinWan-HsinChenChuang, Chi-YaoChi-YaoChuangLiu, Chun-HaoChun-HaoLiuKawakami, NaoyaNaoyaKawakamiPO-HAN CHENKuo, Chia-NungChia-NungKuoLue, Chin-ShanChin-ShanLueLiu, Bo-HongBo-HongLiuWang, Chia-HsinChia-HsinWangJYH PIN CHOULin, Chun-LiangChun-LiangLinLuo, Meng-FanMeng-FanLuo2026-04-132026-04-132025-11-06https://www.scopus.com/record/display.uri?eid=2-s2.0-105034018493&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/737094Transition metal dichalcogenides (TMDs), owing to their two-dimensional (2D) structures, could provide the largest active surface for reactions but consume minimal materials, so become potentially ideal catalysts. Structurally perfect basal planes of TMDs are typically inert whereas their surface defects can serve as catalytically active centers. The generation and control of such surface defects on TMDs thus become highly desired to manipulate their catalytic properties. We exposed PtTe2 and PdTe2 surfaces to methanol near ambient pressure to generate under-coordinated Pt and Pd (denoted as Ptuc and Pduc respectively) at the surfaces. The generation, through the removal of surface Te (Tes), was triggered by a minimal methanol pressure about 10−3 mbar for Ptuc (10−4 mbar for Pduc) and enhanced with increased pressure, and attained a maximum about 10−2 mbar for Ptuc (5 × 10−3 mbar for Pduc) at 300 K. The concentration of surface Pduc was tunable between 0% and 100% simply with an appropriate methanol pressure, despite varied initial concentrations of Tes vacancies on as-prepared PdTe2, whereas, in contrast, the Ptuc was generated in a limited manner dependent on initial concentrations of Tes vacancies ― the generation rate decreased at greater initial ones ― and their appreciable increase induced surface roughening. The Tes was removed largely by the interaction of hydrogen atoms (H) from decomposed methanol with Tes surrounding the vacancies, and subsequent formation and desorption of H2Te. These results suggest, in addition to the known strategies of defect engineering, an alternative approach to engineer surface vacancies on layered 2D materials in a controllable manner.trueambient pressuremethanolPdTe2PtTe2surface defectssurface reactivityjournal article10.1088/2053-1583/ae18e32-s2.0-105034018493