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

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 µm), 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 treatment.DFG, 327886311, SFB 1316: Transiente Atmosphärendruckplasmen - vom Plasma zu Flüssigkeiten zu FestkörpernDFG, 390874152, EXC 2154: POLiS - Post Lithium Storage Cluster of Excellenc

Step Dipole Moment and Step Line Tension on Au(100) in aqueous KBr electrolyte

Here, we demonstrate a new method to measure step dipole moments for electrode surfacesin the presence of specifically adsorbed anion adlayers. The method is based on potential-dependentstudies of the equilibrium shape and the equilibrium fluctuations of monatomic high Au islands asobserved in scanning tunneling microscopy data.Furthermore we measure the angular anisotropy of the absolute step line tension for an Au(100)electrode in contact with KBr solution. A method previously introduced for surfaces in vacuum is nowextended for electode surfaces in contact with electrolyte

Nanoporous Au formation on Au substrates via high voltage electrolysis

Nanoporous Au (NPG) films often show distinctly different properties than bare Au electrodes, which make them suitable for various applications in (electro)catalysis or (bio)sensing. A great deal of effort has gone into finding suitable preparation techniques that can be used to target structural properties, such as the pore size or the surface-to-volume ratio. Many of the methods described for preparing these NPG films require complex starting materials such as alloys, multiple synthesis steps, lengthy preparation procedures or a combination of these factors. Here we present an approach that circumvents these difficulties, enabling for a rapid and controlled preparation of NPG films starting from bare Au electrodes. One approach is to prepare in a first step a Au oxide film by high voltage (HV) electrolysis in a KOH solution, which in a second step is reduced either electrochemically or in the presence of H₂O₂. The resulting NPG structures as well as their electrochemically active surface areas strongly depend on the reduction procedure, the concentration and temperature of the H₂O₂-containing KOH solution, as well as the applied voltage and temperature during the HV electrolysis. The NPG film can also be prepared directly by applying electrolysis voltages that result in anodic contact glow discharge electrolysis (aCGDE) over an extended period of time. By carefully adjusting the corresponding parameters, the surface area of the final NPG film can be specifically controlled. The structural properties of the electrodes are investigated by means of XPS, SEM and electrochemical methods

In Liquid Plasma Mediated Manganese Oxide Electrocatalysts for Quasi Industrial Water Oxidation and Selective Dehydrogenation

The production of renewable feedstocks through the coupled oxygen evolution reaction OER with selective organic oxidation requires a perfect balance in the choice of a catalyst and its synthesis access, morphology, and catalytic activity. Herein we report a rapid in liquid plasma approach to produce a hierarchical amorphous birnessite type manganese oxide layer on 3D nickel foam. The as prepared anode exhibits an OER activity with overpotentials of 220, 250, and 270 mV for 100, 500, and 1000 mA cm 2, respectively, and can spontaneously be paired with chemoselective dehydrogenation of benzylamine under both ambient and industrial 6 M KOH, 65 C alkaline conditions. The in depth ex situ and in situ characterization unequivocally demonstrate the intercalation of potassium in the birnessite type phase with prevalent MnIII states as an active structure, which displays a trade off between porous morphology and bulk volume catalytic activity. Further, a structure activity relationship is realized based on the cation size and structurally similar manganese oxide polymorphs. The presented method is a substantial step forward in developing a robust MnOx catalyst for combining effective industrial OER and value added organic oxidatio

Activation of nickel foam through in liquid plasma induced phosphorus incorporation for efficient quasi industrial water oxidation and selective oxygenation of organics

Developing bifunctional electrodes for oxidation catalysis is highly desirable for hydrogen and value added chemicals production. Herein, we directly activate the nickel foam through the incorporation of elemental P P NF using a facile, controllable, and ultrafast in liquid plasma electrolysis approach. When serving for oxygen evolution reaction OER in 1 M KOH at room temperature, the optimized P NF can afford 500 mA cm amp; 8722;2 at 350 mV, and stabilize this current density for over 120 h. Remarkably, the electrode maintains a stable industrial grade current density in an assembled electrolyzer under quasi industrial conditions 60 amp; 8451; and 6 M KOH for over 107 h. The combination of ex in situ characterizations and theoretic calculations unequivocally illustrates that P incorporation induces an elevated electrode porosity and wettability, increased and immobilized Fe impurity doping, as well as enhanced conductivity, forming active Fe doped amp; 947; NiIIIOOH during OER. The practical bifunctionality of P NF is additionally verified with selective oxygenation of organics forming value added chemical

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 Cu wires via versatile plasma electrolysis is presented. Silica nanoparticles (11 nm) have been introduced during the electrolysis to tailor the surface structure of the Cu electrode. The influence of these silica 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 Cu(II) oxide as a thin outer shell and a significant amount of inner Cu(I) oxide. Furthermore, the oxide film thickness (between 1 and 70 μm), 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 treatment

Kink energy and kink dipole moments on vicinal Au(001) in halide electrolytes

Using electrochemical scanning tunnelling microscopy, we measured the potential-dependent kink energy and the corresponding dipole moments for kinks at step edges on vicinal Au(001) surfaces in chloride and bromide containing electrolyte. Combining the results for the potential dependence of the kink energy with impedance spectroscopy data for the surface charge, we can directly deduce the dipole moment of kinks at the Au steps with co-adsorbed Cl-, respectively Br-. We find μ^Cl= (6.0±0.7) × 10^(-3) eÅ and μ^Br= (10.1±0.6) × 10^(-3) eÅ