کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5426156 1395878 2007 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Surface diffraction study of the hydrated hematite (11¯02) surface
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Surface diffraction study of the hydrated hematite (11¯02) surface
چکیده انگلیسی

The structure of the hydroxylated α-Fe2O3(11¯02) surface prepared via a wet chemical and mechanical polishing (CMP) procedure was determined using X-ray crystal truncation rod diffraction. The experimentally determined surface model was compared with theoretical structures developed from density functional theory (DFT) calculations to identify the most likely protonation states of the surface (hydr)oxo moieties. The results show that the hydroxylated CMP-prepared surface differs from an ideal stoichiometric termination due to vacancies of the near surface bulk Fe sites. This result differs from previous ultra high vacuum studies where two stable terminations were observed: a stoichiometric (1 × 1) termination and a partially reduced (2 × 1) reconstructed surface. The complementary DFT studies suggest that hydroxylated surfaces are thermodynamically more stable than dehydroxylated surfaces in the presence of water. The results illustrate that the best fit surface model has predominantly three types of (hydr)oxo functional groups exposed at the surface at circumneutral pH: Fe-OH2, Fe2-OH, and Fe3-O and provide a structural basis for interpreting the reactivity of model iron-(hydr)oxide surfaces under aqueous conditions.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface Science - Volume 601, Issue 2, 15 January 2007, Pages 460-474
نویسندگان
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