The electrodeposition of Pt on RuO2(110) from acid solutions of several Pt complexes was studied using programmed potential step or potential sweep methods. The RuO2(110) single-crystal surface was obtained by gas-phase oxidation of Ru(0001). The electrodeposition process is characterized by a large crystallization overpotential and three-dimensional growth from a Pt adlayer. The mismatch between the RuO2(110) and Pt lattices is the likely origin of that overpotential. The nucleation is instantaneous, as verified by potential step experiments. The process starts with depositing a 0.25 ML of Pt, with Pt atoms arranged in a c(2 x 2) array, which is followed by the growth of Pt islands and three-dimensional clusters as in the Stranski-Krastanov growth mode. Density functional theory calculations were used to help in elucidating atomically resolved electrochemical scanning tunneling microscopy (ECSTM) images of the initial stages of Pt deposition. A Pt adlayer on RuO2(110) has lower catalytic activity for the oxygen reduction reaction compared to Pt, which is in agreement with a large calculated upshift of the d-band center of a low-coverage Pt deposit on RuO2-(110) as well as a lack of the oxygen adsorption in a bridge configuration on that surface.
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机译：使用程序化的电势阶跃或电势扫描方法研究了Pt在RuO2（110）上从几种Pt配合物的酸性溶液中的电沉积。通过Ru（0001）的气相氧化获得RuO 2（110）单晶表面。电沉积过程的特征在于大的结晶超电势和Pt吸附层的三维生长。 RuO2（110）和Pt晶格之间的不匹配是该超电势的可能起因。如可能的分步实验所证实，成核是瞬时的。该过程开始于沉积0.25 ML的Pt，Pt原子以c（2 x 2）阵列排列，然后像Stranski-Krastanov生长模式一样，生长Pt岛和三维簇。密度泛函理论计算可用于阐明Pt沉积初始阶段的原子分辨电化学扫描隧道显微镜（ECSTM）图像。与Pt相比，RuO2（110）上的Pt吸附层对氧还原反应的催化活性较低，这与RuO2-（110）上低覆盖率Pt沉积物的d谱带中心的大计算出的上移量相符，即以及在该表面上的桥结构中缺乏氧吸附。
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