scholarly journals Dealloying Behavior of NiCo and NiCoCu Thin Films

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Benjamin E. Peecher ◽  
Jennifer R. Hampton

Porous metals and alloys, such as those fabricated via electrochemical dealloying, are of interest for a variety of energy applications, ranging from their potential for enhanced catalytic behavior to their use as high surface area supports for pseudocapacitor materials. Here, the electrochemical dealloying process was explored for electrodeposited binary NiCo and ternary NiCoCu thin films. For each of the four different metal ratios, films were dealloyed using linear sweep voltammetry to various potentials in order to gain insight into the evolution of the film over the course of the linear sweep. Electrochemical capacitance, scanning electron microscopy, and energy dispersive X-ray spectroscopy were used to examine the structure and composition of each sample before and after linear sweep voltammetry was performed. For NiCo films, dealloying resulted in almost no change in composition but did result in an increased capacitance, with greater increases occurring at higher linear sweep potentials, indicating the removal of material from the films. Dealloying also resulted in the appearance of large pores on the surface of the high nickel percentage NiCo films, while low nickel percentage NiCo films had little observable change in morphology. For NiCoCu films, Cu was almost completely removed at linear sweep potentials greater than 0.5 V versus Ag/AgCl. The linear sweep removed large Cu-rich dendrites from the films, while also causing increases in measured capacitance.

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2609
Author(s):  
Abniel Machín ◽  
Kenneth Fontánez ◽  
Juan C. Arango ◽  
Dayna Ortiz ◽  
Jimmy De León ◽  
...  

At present, the world is at the peak of production of traditional fossil fuels. Much of the resources that humanity has been consuming (oil, coal, and natural gas) are coming to an end. The human being faces a future that must necessarily go through a paradigm shift, which includes a progressive movement towards increasingly less polluting and energetically viable resources. In this sense, nanotechnology has a transcendental role in this change. For decades, new materials capable of being used in energy processes have been synthesized, which undoubtedly will be the cornerstone of the future development of the planet. In this review, we report on the current progress in the synthesis and use of one-dimensional (1D) nanostructured materials (specifically nanowires, nanofibers, nanotubes, and nanorods), with compositions based on oxides, nitrides, or metals, for applications related to energy. Due to its extraordinary surface–volume relationship, tunable thermal and transport properties, and its high surface area, these 1D nanostructures have become fundamental elements for the development of energy processes. The most relevant 1D nanomaterials, their different synthesis procedures, and useful methods for assembling 1D nanostructures in functional devices will be presented. Applications in relevant topics such as optoelectronic and photochemical devices, hydrogen production, or energy storage, among others, will be discussed. The present review concludes with a forecast on the directions towards which future research could be directed on this class of nanostructured materials.


RSC Advances ◽  
2015 ◽  
Vol 5 (6) ◽  
pp. 4443-4447 ◽  
Author(s):  
S. K. Shinde ◽  
D. P. Dubal ◽  
G. S. Ghodake ◽  
V. J. Fulari

We present a novel route for the synthesis of CuO thin films. The nano-flower like nanostructures provide high surface area, and the CuO shows excellent supercapacitive properties.


ACS Nano ◽  
2013 ◽  
Vol 7 (4) ◽  
pp. 2999-3013 ◽  
Author(s):  
Pascal Hartmann ◽  
Torsten Brezesinski ◽  
Joachim Sann ◽  
Andriy Lotnyk ◽  
Jens-Peter Eufinger ◽  
...  

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 24
Author(s):  
Marion Duparc ◽  
Henrik Hovde Sønsteby ◽  
Ola Nilsen ◽  
Anja Olafsen Sjåstad ◽  
Helmer Fjellvåg

Thin films of the catalytically interesting ternary and quaternary perovskites GdCoO3 and Gd0.9Ca0.1CoO3 are fabricated by atomic layer deposition using metal β-diketonates and ozone as precursors. The resulting thin films are amorphous as deposited and become single-oriented crystalline on LaAlO3(100) and YAlO3(100/010) after post-annealing at 650 °C in air. The crystal orientations of the films are tunable by choice and the orientation of the substrate, mitigated through the interface via solid face epitaxy upon annealing. The films exhibit no sign of Co2+. Additionally, high-aspect-ratio Si(100) substrates were used to document the suitability of the developed process for the preparation of coatings on more complex, high-surface-area structures. We believe that coatings of GdCoO3 and Gd1−xCaxCoO3 may find applications within oxidation catalysis.


2002 ◽  
Vol 54 (1-2) ◽  
pp. 97-103 ◽  
Author(s):  
Mats Lundberg ◽  
Björn Skårman ◽  
Fredrik Cesar ◽  
L Reine Wallenberg

2016 ◽  
Vol 720 ◽  
pp. 252-256
Author(s):  
Nadia Mohammed Elmassalami Ayad ◽  
Andre Ben Hur da Silva Figueiredo ◽  
Wilma de Araujo Gonzalez ◽  
Daniel Navarro da Rocha ◽  
Rubens Lincoln Santana Blazutti Marçal ◽  
...  

Bioactive glasses have widely used in biomedical applications such as bone filler due to their excellent biocompatibility, bioactivity and osteoconduction characteristics. In this work, a silicate-rich glass was synthesized by the sol-gel method with 60% SiO2 – 30%CaO – 10% MgO composition where fumed silica acts as the silica precursor. This new method was hypothesized to reduce the gel formation time, due to the high surface area of the fumed silica. In addition, this would presumably increase the nanoporosity of the glass. For comparison purposes, we used a glass of the same composition, but with the conventional silica precursor, tetraethyl orthosilicate (TEOS), through the sol gel method. Both were heat treated at 450°C. FT-IR analysis before and after heat treatment at 450°C showed the presence of nitrate groups, especially in the TEOS samples. This is consistent with the more hygroscopic aspect of those samples. The fumed silica samples had significantly less pronounced peaks corresponding to the nitrate groups, consistent with the more porous structure and the less hygroscopic aspect. The fumed silica samples indeed had a lower gelling time and showed similar results obtained by XRD and FT-IR analyses, showing that the use of fumed silica is viable and advantageous in the glass synthesis by the sol-gel process


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