In Liquid Plasma for Surface Engineering of Cu Electrodes with Incorporated SiO2 Nanoparticles From Micro to Nano

A robust and efficient route to modify the chemical and physical properties of polycrystalline copper Cu wires via versatile plasma electrolysis is presented. Silica SiO2 nanoparticles 11 nm are introduced during the electrolysis to tailor the surface structure of the Cu electrode. The influence of these SiO2 nanoparticles on the structure of the Cu electrodes during plasma electrolysis over a wide array of applied voltages and processing time is investigated systematically. Homogeneously distributed 3D coral like microstructures are observed by scanning electron microscopy on the Cu surface after the in liquid plasma treatment. These 3D microstructures grow with increasing plasma processing time. Interestingly, the microstructured copper electrode is composed of CuO as a thin outer layer and a significant amount of inner Cu2O. Furthermore, the oxide film thickness between 1 and 70 m , the surface morphology, and the chemical composition can be tuned by controlling the plasma parameters. Remarkably, the fabricated microstructures can be transformed to nanospheres assembled in coral like microstructures by a simple electrochemical treatmen

Initial Stages of Pd Deposition onto Au(111) Electrodes from PdSO_4 Solution

　应用电化学扫描隧道显微镜(ECSTM)研究了PdSO4溶液中Au(111)电极表面Pd的电化学沉积过程.实验表明,Pd的沉积初始阶段在Au(111)电极表面依次生成两个满单层Pd膜,这一实验结果不仅与电位扫描一致,而且更进一步地证明了起初的两个Pd单层形成过程乃以层～层外延方式生长.高分辨的原子图像表明吸附的SO2-4离子在外延生长的Pd膜表面形成了有序的(3×7)R19°结构.Metal thin films have attracted considerable interest in relation to catalysis, energy, material, corrosion and environmental protection. Pd thin film is capable of proton reduction and strong hydrogen absorption, which has shown electrocatalytic activity to the oxidation of small organic molecules. In this paper, in_situ STM measurements are performed to study the deposition process and the influence of the surface structure and anion adsorption. When Pd is deposited from PdSO4 solution on Au(111) in the UPD range, a monolayer of Pd with pseudomorphic (1×1) structure was formed on the substrate with induced (3×7) R19° SO2-4 adsorption. With decreasing potential the OPD range, the second pseudomorphic monolayer is formed with induced SO2-4 adsorption similar to that on the first monolayer. When the Pd reaches more than two monolayers, the deposition process changes to follow three_dimensional growth model with increased defects. Pd deposition from PdSO4 on Au (111) (1×1) follows the epitaxial way to form two complete monolayers of Pd film, in which induced anion adsorption on Pd film could play an important role.作者联系地址：厦门大学化学系,大学电化学系,大学电化学系,Ulm大学电化学系 福建厦门361005 ,89069 Ulm德国 ,89069 Ulm德国 ,89069 Ulm德国Author's Address: 1.Department of chemistry, Xiamen 361005,China,2.Department of Electrochemistry, University of Ulm, 89069 Ulm, German

Temperature-dependent kinetic studies of the chlorine evolution reaction over RuO2(110) model electrodes

Ultrathin single-crystalline RuO 2(110) films supported on Ru(0001) are employed as model electrodes to extract kinetic information about the industrially important chlorine evolution reaction (CER) in a 5M concentrated NaCl solution under well-defined electrochemical conditions and variable temperatures. A combination of chronoamperometry (CA) and online electrochemical mass spectrometry (OLEMS) experiments provides insight into the selectivity issue: At pH = 0.9, the CER dominates over oxygen evolution, whereas at pH = 3.5, oxygen evolution and other parasitic side reactions contribute mostly to the total current density. From temperature-dependent CA data for pH = 0.9, we determine the apparent free activation energy of the CER over RuO 2(110) to be 0.91 eV, which compares reasonably well with the theoretical value of 0.79 eV derived from first-principles microkinetics. The experimentally determined apparent free activation energy of 0.91 eV is considered as a benchmark for assessing future improved theoretical modeling from first principles

High energy states of gold and their importance in electrocatalytic processes at surfaces and interfaces

The ability of metals to store or trap considerable amounts of energy, and thus exist in a non-equilibrium or metastable state, is very well known in metallurgy; however, such behaviour, which is intimately connected with the defect character of metals, has been largely ignored in noble metal surface electrochemistry. Techniques for generating unusually high energy surface states for gold, and the unusual voltammetric responses of such states, are outlined. The surprisingly high (and complex) electrocatalytic activity of gold in aqueous media is attributed to the presence of a range of such non-equilibrium states as the vital entities at active sites on conventional gold surfaces. The possible relevance of these ideas to account for the remarkable catalytic activity of oxide-supported gold microparticles is briefly outlined