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Hydrogen evolution reaction (HER) activity of conical Co–Fe alloy structures and their application as a sensitive and rapid sensor for H2O2 detection

Skibińska Katarzyna, Kutyła Dawid, Kula Anna, Gajewska Marta, Marzec Mateusz M., Żabiński Piotr

Archives of Civil and Mechanical Engineering

2022

Vol. 22, no. 2

art. no. e76, 1--10

In this work, the conical Co–Fe alloy structures were synthesized by two different methods: a two- and a one-step. The synthesis of nanoconical structures with regular, well-defined geometrical features, called the two-step method, requires using porous Anodic Alumina Oxide (AAO) templates. Contrary, any advanced pre-preparation of the substrate is not necessary for the one-step method. The fabrication of cones is carried out from the electrolyte containing an addition of a crystal modifier. Co and Fe are applied as electrodes in an alkaline environment. Their catalytic performance can be enhanced by modification of the shape and size of their structures, and in consequence, developing their active surface area. Many methods were used to analyze the coatings, such as Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray Spectroscopy (EDS), Energy-Dispersive X-ray Spectrometry (EDAX), X-ray Photoelectron Spectroscopy (XPS), and X-ray diffraction analysis (XRD). The catalytic properties of the coatings were recorded during the hydrogen evolution reaction and the reduction of the hydrogen peroxide and compared with the catalytic activity of bulk alloy. Nanocones produced in AAO templates were characterized by significantly higher catalytic activity and sensitivity in both reactions. However, they were unstable in the time of the experiment duration. Cones synthesized by the one-step method can be successfully applied as a catalyst and H2O2 detector.

Study on Synthesis and Modification of Conical Ni Structures by One-Step Method

Skibińska K., Semeniuk S., Kutyła D., Kołczyk-Siedlecka K., Jędraczka A., Żabiński P.

Archives of Metallurgy and Materials

2021

Vol. 66, iss. 3

861--869

In this work the conical Ni structures were obtained from an electrolyte containing NH4Cl as a crystal modifier. This process is called one-step method and allows to cover large areas with micro- and nanostructures during a single electrodeposition. Presence of NH4Cl promotes a vertical direction of structure growth in order to block a horizontal one. Additionally, this method does not require using chromic acid solution, which is dangerous for the environment. Due to the ferromagnetic properties of Ni, obtained coatings could be applied as magnetic devices. The influence of the parameters such as a preparation of copper substrate, a composition of electrolyte and electrodeposition conditions (time, the electrolyte temperature and current density) was investigated in this work.

Synthesis of conical Co–Fe alloys structures obtained with crystal modifier in superimposed magnetic field

Skibińska Katarzyna, Kutyła Dawid, Kołczyk-Siedlecka Karolina, Marzec Mateusz M., Żabiński Piotr, Kowalik Remigiusz

Archives of Civil and Mechanical Engineering

2021

Vol. 21, no. 4

507--517

The addition of crystal modifier to electrolyte used during electrodeposition of metals and alloys allows obtaining conical structures without using any template. This method is fast and ensures covering large areas during one single electrodeposition process. In this work, Co–Fe cones were obtained by one-step method with ammonium chloride as a crystal modifier. The influence of electrodeposition parameters and electrolyte compositions were investigated. Electrodeposition conditions (duration, electrolyte temperature, and addition of NH4Cl), which allow obtaining the most uniform conical structures, were applied during sample fabrication in the magnetic field. The influence of its value and direction on the quality and compositions of obtained alloys was investigated using Scanning Electron Microscope (SEM) photos. To check if there is any change in the sample crystal system, the X-Ray Diffraction (XRD) analysis was performed. To confirm the synthesis of Co–Fe cones, they were analyzed using the X-ray photoelectron Spectroscopy (XPS) method.