Group of Catalytic Reaction Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
Langmuir. 2011 Jun 21;27(12):7909-16. doi: 10.1021/la201007m. Epub 2011 May 19.
Poly(vinylpyrrolidone) (PVP)-stabilized Pd nanocubes were synthesized, deposited on a carbon-based support, and subsequently treated with UV-ozone (UVO) in order to eliminate the traces of PVP still present on the surface. Cubes, being a thermodynamically unfavorable shape, are very prone to restructuring to minimize the interfacial free energy and thus allow the assessment of their morphological stability during UVO cleaning. The process of PVP removal was monitored by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and in situ attenuated total reflection infrared spectroscopy (ATR-IR). High-resolution scanning electron microscopy (SEM) imaging was used to evaluate the morphology of the nanocubes. The effect of PVP removal was also studied in the hydrogenation of acetylene, showing a 4-fold increase of activity. This method can be applied to nanoparticles of other common shapes, which expose different crystal planes, in order to study the structure sensitivity of chemical reactions.
聚（乙烯基吡咯烷酮）（PVP）稳定的 Pd 纳米立方体被合成，沉积在碳载体上，然后用 UV-臭氧（UVO）处理，以去除表面上仍存在的 PVP 痕迹。由于立方体是一种热力学上不利的形状，因此它们非常容易重构以最小化界面自由能，从而允许在 UVO 清洗过程中评估它们的形态稳定性。通过 X 射线光电子能谱（XPS）、X 射线衍射（XRD）和原位衰减全反射红外光谱（ATR-IR）监测 PVP 去除过程。高分辨率扫描电子显微镜（SEM）成像用于评估纳米立方体的形态。还研究了 PVP 去除对乙炔加氢反应的影响，发现活性提高了 4 倍。该方法可应用于暴露不同晶面的其他常见形状的纳米颗粒，以研究化学反应的结构敏感性。
