scholarly journals Electrocatalytic Properties of Co Nanoconical Structured Electrodes Produced by a One-Step or Two-Step Method

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 544
Author(s):  
Katarzyna Skibinska ◽  
Karolina Kolczyk-Siedlecka ◽  
Dawid Kutyla ◽  
Anna Jedraczka ◽  
Beata Leszczyńska-Madej ◽  
...  

One-dimensional (1D) nanostructures, such as nanotubes, nanopores, nanodots and nanocones, are characterized by better catalytic properties than bulk material due to their large active surface area and small geometrical size. These structures can be produced by several methods of synthesis including the one- and two-step methods. In the one-step method, a crystal modifier is added to the solution in order to limit the horizontal direction of structures growing during electrodeposition. In this work, NH4Cl was used as a crystal modifier. Another way of production of 1D nanocones is the electrodeposition of metal in porous anodic alumina oxide (AAO) templates, called the two-step method. In this case, the AAO template was obtained using a two-step anodization process. Nanocones obtained by the two-step method show smaller geometrical size. In this work, cobalt nanoconical structures were obtained from an electrolyte containing CoCl2 and H3BO3. The electrocatalytic properties of materials fabricated by one-step and two-step methods were measured in 1 M NaOH and compared with bulk material electrodeposited from the same electrolyte. There were several microshell structures in the case of Co deposits obtained by the one-step method. To solve this problem, different conditions of synthesis Co cones by the one-step method were applied. The electrocatalytic activity of these samples was checked as well.

2020 ◽  
Vol 2 (1) ◽  
pp. 12
Author(s):  
Katarzyna Skibinska ◽  
Karolina Kolczyk-Siedlecka ◽  
Dawid Kutyla ◽  
Anna Jedraczka ◽  
Piotr Zabinski

One-dimensional (1D) nanostructures, such as nanotubes, nanopores, nanodots and nanocones, are characterized by better catalytic properties than bulk materials due to their large active surface area and small geometrical size. There are several methods of synthesis for these structures, including the one- and two-step methods. In the one-step method, a crystal modifier is added to the solution in order to limit the horizontal direction of structures growing during electrodeposition. In this work, cobalt nanoconical structures were obtained from an electrolyte containing CoCl2, H3BO3 and NH4Cl as the crystal modifier. Another method of production of 1D nanocones is electrodeposition of the metal into porous anodic alumina oxide (AAO) templates. This method is called the two-step method. In this case, an AAO template was obtained using two-step anodization. Then, electrodeposition of cobalt was performed from an electrolyte containing CoSO4 and H3BO3. Nanocones obtained by the two-step method show smaller geometrical size. The bulk sample was electrodeposited from the same electrolyte. The electrocatalytic properties of materials fabricated by the one-step and two-step methods were measured in 1M NaOH and compared with bulk materials. Co cones obtained by the one-step method show the worst electrocatalytic properties. The hydrogen evolution reaction started the earliest for Co nanocones electrodeposited in the templates.


2010 ◽  
Vol 25 (9) ◽  
pp. 1755-1760 ◽  
Author(s):  
Changsheng Shan ◽  
Dongxue Han ◽  
Jiangfeng Song ◽  
Ari Ivaska ◽  
Li Niu

Flowerlike submicrometer gold particles were synthesized through a simple one-step method using p-diaminobenzene as a reductant in the presence of poly(sodium 4-styrenesulfonate) in aqueous solution. The particle size with diameters ranging from 267 to 725 nm could be tuned by varying the molar ratio of poly(sodium 4-styrenesulfonate) to HAuCl4, which also resulted in tunable roughness. The gold particles were confirmed by scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. Cyclic voltammetry showed that the specific surface area of the flowerlike particles was larger than that of sphere particles. The obtained flowerlike particles with higher surface area also exhibited higher electrocatalytic activity toward H2O2 and O2. The increase of electrocatalytic activity could be attributed to the increase of the active surface area.


2020 ◽  
Vol 29 (12) ◽  
pp. 8025-8035
Author(s):  
Katarzyna Skibinska ◽  
Grzegorz Smola ◽  
Lukasz Bialo ◽  
Dawid Kutyla ◽  
Karolina Kolczyk-Siedlecka ◽  
...  

AbstractAnodization is a widespread surface treatment method for aluminum and its alloys; it also allows the formation of 1D nanostructures by a two-step process. Microstructure of the Al substrate and crystallographic texture after rolling and annealing have influence on the properties of AAO templates with conical nanopores. Synthesized free-standing 1D nanostructures ensure better electrocatalytic properties than bulk materials due to larger active surface area. In this work, the influence of annealing time at 500 °C on Vickers hardness and microstructure of aluminum AA1050 used in a two-step anodization process was investigated. The geometrical features of the templates such as interpore distance and number of pores per 1 μm2 were determined and compared. There is dependence between the time of the annealing process and surface quality of synthesized 1D Cu nanocone layers. The template, after 1 h of annealing, due to the largest active area and satisfactory quality of the nanocone surface, was chosen for synthesis of Co nanocones. The electrocatalytic properties of samples were measured in 1 M NaOH solution and compared with bulk material electrodeposited in the same conditions. The open circuit potential, connected with starting of hydrogen evolution reaction, was determined from the LSV curves. Active surface areas were determined for all samples using SEM photographs and taken into consideration during electrocatalytic tests. Possible behavior of hydrogen bubbles for the formation of nanostructures was considered.


Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 327 ◽  
Author(s):  
Caterina Gaudiuso ◽  
Annalisa Volpe ◽  
Antonio Ancona

We report on a one-step method for cutting 250-µm-thick quartz plates using highly focused ultrashort laser pulses with a duration of 200 fs and a wavelength of 1030 nm. We show that the repetition rate, the scan speed, the pulse overlap and the pulse energy directly influence the cutting process and quality. Therefore, a suitable choice of these parameters was necessary to get single-pass stealth dicing with neat and flat cut edges. The mechanism behind the stealth dicing process was ascribed to tensile stresses generated by the relaxation of the compressive stresses originated in the laser beam focal volume during irradiation in the bulk material. Such stresses produced micro-fractures whose controlled propagation along the laser beam path led to cutting of the samples.


1990 ◽  
Vol 9 (3) ◽  
pp. 247-252 ◽  
Author(s):  
Sander Greenland ◽  
Alberto Salvan
Keyword(s):  
One Step ◽  

2018 ◽  
Vol 54 (68) ◽  
pp. 9438-9441 ◽  
Author(s):  
Nathalie M. Pinkerton ◽  
Khadidja Hadri ◽  
Baptiste Amouroux ◽  
Leah Behar ◽  
Christophe Mingotaud ◽  
...  

A novel, one-step method for the synthesis of functional, organic–inorganic hybrid nanoparticles is reported.


Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 658 ◽  
Author(s):  
Xiaohui Yang ◽  
Yi Liu ◽  
Chunjie Yan ◽  
Ronghua Peng ◽  
Hongquan Wang

Geopolymer-TiO2 nanocomposites were prepared by two different techniques, namely the two-step acidification calcination treatment and one-step adding method. The potential photocatalytic activities of geopolymer-TiO2 nanocomposites prepared by the two different methods were tested and compared. Nanocomposites prepared via the one-step process showed better photocatalytic activity. The amount of TiO2 particles loaded on the surface of the foaming materials was investigated by XRD and SEM-Mapping. By comparing with the sample obtained from two-step treatment, the TiO2 particles were distributed uniformly on the surface of the foaming materials for the sample obtained from the one-step method in this study. Results showed that the specific surface area of the geopolymer-TiO2 prepared by the one-step treatment process (28.67 m2/g) was significantly lower than the two-step acidification calcination process (215.04 m2/g), while the photocatalytic efficiency with methylene blue trihydrate (MB) was better. This is due to the more stable structure of geopolymer-TiO2 nanocomposites, the better dispersion and more loading of TiO2 particles on the foaming materials surfaces, leading to the enhanced photocatalytic activity.


2020 ◽  
Vol 20 (12) ◽  
pp. 7333-7341
Author(s):  
Feng Chen ◽  
Jing-Hao Li ◽  
Yu-Chen Chi ◽  
Zhen-Hua Dan ◽  
Feng-Xiang Qin

A unique nanostructured electrocatalyst based on Palladium (Pd) nanosponge architecture is synthesized by one-step dealloying of the amorphous alloy precursor with low Pd concentration. The sponge-like nanostructure with hollow interiors enables sufficient contact between reactants andboth the interior and exterior surfaces. The results of cyclic voltammetry reveal that the as-prepared Pd nanosponge exhibits high sensitivity of 32 μA mM−1 cm−2 in a wide linear range (1–18 mM), and long-term stability toward glucose electro-oxidation. The Pd nanosponge also manifests detection limit as low as 2.0 μM (S/N = 3) and high selectivity for glucose sensing. The enhanced catalytic activity of the Pd nanosponge is attributed to the bimetallic synergistic effect and the large active surface area of the high-uniformity porous structure. The facile synthesis of the cost-effective Pd nanosponge with superior electrocatalytic performance makes it hold great potentials for biosensor and other catalysis applications.


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