Faculty of Chemistry, Physical Chemistry I, Bielefeld University, 33615 Bielefeld, Germany.
Institute of Physical Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55099 Mainz, Germany.
Phys Chem Chem Phys. 2023 May 10;25(18):12694-12701. doi: 10.1039/d3cp01159c.
Calcite is the most abundant carbonate mineral in Earth's crust. Upon cleavage, the (10.4) plane with a rectangular unit cell is exposed. Interestingly, several experiments suggest a (2 × 1) surface reconstruction. However, clear experimental evidence and a theoretical confirmation were long missing. Recently, convincing indication for a (2 × 1) reconstruction has been given by atomic force microscopies taken at 5 K. Here, we show temperature-programmed desorption (TPD) experiments of water and ethanol desorbing from calcite (10.4) around room temperature. The TPD curves fit excellently to a kinetic model considering two different adsorption sites, as expected in case of a (2 × 1) reconstruction. This finding applies to the desorption of water and ethanol, illustrating that the effect is characteristic for the calcite cleavage plane. Our results thus show that the (2 × 1) reconstruction not only exists at room temperature but has significant impact on the interfacial properties of calcite.
方解石是地壳中最丰富的碳酸盐矿物。解理时，暴露的是具有矩形单位晶格的（10.4）面。有趣的是，几项实验表明存在（2×1）表面重构。然而，长期以来，明确的实验证据和理论确认都缺乏。最近，在 5 K 下进行的原子力显微镜研究给出了令人信服的（2×1）重构的证据。在这里，我们展示了室温附近方解石（10.4）上水和乙醇解吸的程序升温脱附（TPD）实验。TPD 曲线与考虑两种不同吸附位的动力学模型非常吻合，这在（2×1）重构的情况下是预期的。这一发现适用于水和乙醇的解吸，表明该效应是方解石解理面的特征。因此，我们的结果表明，（2×1）重构不仅存在于室温下，而且对方解石的界面性质有重要影响。
