Removal of surfactant and capping agent from Pd nanocubes (Pd-NCs) using tert-butylamine: its effect on electrochemical characteristics

Vidal‐Iglesias

Current Opinion in Electrochemistry

et al. 2017

The use of shape-controlled metal nanoparticles has produced not only a clear enhancement in the electrocatalytic activity of different reactions of interest but also a better understanding of the effect of the surface structure on nanoscaled materials. However, it is well-accepted that a correct understanding of the correlations between shape/surface structure and electrochemical reactivity indispensably requires the use of clean surfaces. In this regard, and considering that most of the synthetic methodologies available in the literature for the preparation of these shaped metal nanoparticles employ capping agents, the development of effective surface cleaning methodologies able to remove such capping agents from the surface of the corresponding nanoparticles, becomes an extremely important prerequisite to subsequently evaluate their electrocatalytic properties for any reaction of interest.Consequently, in this contribution, we summarize the most relevant advances about surface cleaning procedures applied to different shaped metal nanoparticles for electrocatalytic purposes. It is worth mentioning that this work will only include contributions in which the surface cleanness of the samples is specifically evaluated using well-established electrochemical tools.

Section: Surface Cleaning Methodologiesmentioning

confidence: 99%

Electrocatalysis on shape-controlled metal nanoparticles: Progress in surface cleaning methodologies

Vidal‐Iglesias

Current Opinion in Electrochemistry

et al. 2017

“…The lower activity may partially come from the fact that the relative proportion of the most active (100) surface facets is lower for smaller nanocubes, due to the effect of truncation. Another reason may be that PVP is not completely removed from the catalysts surface and blocks the active sites of PdNPs from the access of O 2 molecules [44].…”

Section: Oxygen Reduction Reaction Studiesmentioning

confidence: 99%

Oxygen electroreduction on carbon-supported Pd nanocubes in acid solutions

Erikson

Lüsi

Sarapuu

et al. 2016

Electrochimica Acta

Please cite this article as: Heiki Erikson, Madis Lüsi, Ave Sarapuu, Kaido Tammeveski, Jose Solla-Gullón, Juan M.Feliu, Oxygen electroreduction on carbon-supported Pd nanocubes in acid solutions, Electrochimica Acta http://dx.doi.org/10.1016/j.electacta. 2015.11.125 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Oxygen electroreduction on carbon-supported Pd nanocubes in acid solutions Highlights• Carbon-supported Pd nanocubes of three different size and loading were prepared• The specific activity for oxygen reduction reaction is independent of Pd content• Pd nanocubes possess higher specific activity for ORR than spherical Pd nanoparticles• The ORR on carbon-supported Pd nanocubes proceed mainly via 4-electron pathway• Tafel behaviour of ORR on carbon-supported Pd nanocubes is similar to that of bulk Pd AbstractThe oxygen reduction reaction (ORR) was studied on carbon-supported cubic palladium nanoparticles of different sizes (~30 nm, ~10 nm and ~7 nm). Cetyltrimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP) were used as capping agents to prepare the nanocubes and Pd content in the catalyst samples was 20 and 50 wt%. The surface morphology of the prepared materials was studied by transmission electron microscopy (TEM). The catalyst materials were electrochemically characterised by cyclic voltammetry and CO stripping experiments. The rotating disk electrode (RDE) method was employed for ORR studies in 0.5 M H 2 SO 4 and 0.1 M HClO 4 solutions. The ORR results revealed that the specific activity of cubic Pd nanoparticles is higher than that of spherical Pd particles and does not depend on the Pd content in the catalyst, but decreases with decreasing the size of Pd nanocubes. Mass activity of Pd nanocubes increased with decreasing the particle size. The ORR proceeds mainly via 4-electron pathway and the reaction mechanism is similar to that on bulk Pd.

“…Since many of them are water soluble, attempts have been made to remove them by washing, for instance under water reflux at 90˝C in the case of PVA [58,59], and 20% of PVA could be removed and gold particles in Au/TiO 2 only slightly increased in size. PVP and some organothiols were removed by washings with solutions containing NaBH 4 and/or tert-butylamine followed by washing in ethanol/acetone without affecting the size of the NPs [60][61][62]. Acidic treatments have also been efficient in some cases [63,64].…”

Section: Reduction-deposition (Deposition Of Preformed Metal Nanopartmentioning

confidence: 99%

Chemical Preparation of Supported Bimetallic Catalysts. Gold-Based Bimetallic, a Case Study

Louis

2016

Catalysts

This review focuses on the chemical methods used to prepare supported bimetallic heterogeneous catalysts, i.e., bimetallic nanoparticles deposited on a support. The review is limited to the preparation of gold-based bimetallic catalysts and moreover to bimetallic nanoparticles supported on powder inorganic supports, i.e., on the surface or in the porosity, and not on model supports such as single crystals.