Paula Sebastian Pascual- Professor (Assistant) at KTH Royal Institute of Technology
Paula Sebastian Pascual
- Professor (Assistant) at KTH Royal Institute of Technology
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61
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Introduction
Skills and Expertise
Current institution
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October 2013 - October 2015
Publications
Publications (61)
Electrochemical oxidation-reduction processes in the presence of anions have been widely explored for surface preparation of tailor-made copper catalysts. Nevertheless, the role of the anion and which sites geometries induce remains elusive. To address this uncertainty, we have assessed the effect of chloride on the surface modification of a well-d...
Copper is an active electrocatalyst for various energy conversion reactions, but its performance depends on the structure of the active surface sites. In this work, we propose a simple strategy to tailor both the roughness and the active site's geometry of copper. To modify the surface of copper, we oxidize and reduce a copper polycrystalline elect...
Front cover - EES Catalysis "Toward understanding CO oxidation on high-entropy alloy electrocatalysts"
The electrochemical carbon dioxide reduction (CO2RR) on Cu-based catalysts is a promising strategy to store renewable electricity and produce valuable C2+ chemicals. We investigate the CO2RR on Cu-Ag nanostructures that have been electrodeposited in a green choline chloride and urea deep eutectic solvent (DES). We determine the electrochemically ac...
Understanding the catalytic activity of high-entropy alloys (HEAs) toward the conversion of small molecules such as carbon monoxide (CO) can provide insight into their structure–property relations. The identification of specific descriptors that govern the CO oxidation on HEAs is crucial to design new materials with customized compositions and stru...
Copper is an active electrocatalyst for different energy conversion reactions which performance depends on the structure of the surface active sites. Here we propose a simple strategy to generate (n10) or (100)x(110) motifs on copper with tailored roughness. We electrochemically oxidize and reduce a copper electrode in solutions containing a mixtur...
The green transition requires new, clean, inexpensive, and sustainable strategies to prepare controllable bimetallic and multimetallic nanostructures. Cu−Ag nanostructures, for example, are promising bimetallic catalysts for different electrocatalytic reactions such as carbon monoxide and carbon dioxide reduction. In this work, we present the one‐s...
The electrochemical reduction of carbon dioxide (CO2RR) to valuable C2+ liquid fuels and oxygenates, such as ethanol and propanol, is a promising strategy to minimize the carbon footprint and store renewable electricity. In this study, we investigate the CO2RR on electrodeposited Cu-Ag nanostructures obtained using a green choline chloride and urea...
Electrocatalytic reactions are sensitive to the catalyst surface structure. Therefore, finding methods to determine active surface sites with different geometry is essential to address the structure–electrocatalytic performance relationships. In this work, we propose a simple methodology to tune and quantify the surface structure on copper catalyst...
Electrocatalytic reactions are sensitive to the catalyst surface structure. Therefore, finding methods to determine and quantify active surface sites with different geometry is essential to address the structure-electrocatalytic performance relationships. In this work, we propose a simple methodology to tune and quantify the surface structure on co...
Electrochemical CO2 reduction is an attractive option for storing renewable electricity and for the sustainable production of valuable chemicals and fuels. In this roadmap, we review recent progress in fundamental understanding, catalyst development, and in engineering and scale-up. We discuss the outstanding challenges towards commercialization of...
The green transition requires new strategies to develop active and stable nanomaterials for energy conversion. We describe the preparation of Pd-Au bimetallic nanocatalysts using a surfactant-free electrodeposition method in a deep eutectic solvent (DES) and test their electrocatalytic performance for the formic acid oxidation reaction (FAOR). We u...
The green transition requires new strategies to develop active and stable nanomaterials for energy conversion. We describe, for the first time, the preparation of Pd-Au bimetallic nanocatalysts using a surfactant-free electrodeposition method in a deep eutectic solvent (DES) and test their electrocatalytic performance for the formic acid oxidation...
The green transition requires new strategies to develop active and stable nanomaterials for energy conversion. We describe, for the first time, the preparation of Pd-Au bimetallic nanocatalysts using a surfactant-free electrodeposition method in a deep eutectic solvent (DES) and test their electrocatalytic performance for the formic acid oxidation...
The interplay between the structure and composition of the electric double layer and the surface charge controls the electrocatalytic activity of reactions central to decarbonisation of chemical fuels and materials. The employed electrolyte can affect the charge distribution and the electric field on the interface, which also alters the local pH an...
Cu electrodes are model catalysts for a wide variety of interesting energy conversion reactions. Structure sensitivity typically plays an important role in the mechanism of different electrocatalytic reactions. However, quantifying the presence of different domains on Cu electrocatalysts remains a challenge. Herein, we evaluate the lead (Pb) underp...
Preparation of nanostructured materials with highly efficient active area is crucial for advancement in fields of electrocatalytic conversion of energy, energy storage, or biomedicine. In this regard, there are two main challenges in the electrochemical preparation of high-extended surface area of the nanostructures: 1) establishing the optimal pot...
Our sustainable future requires finding new, affordable and green routes to prepare nanostructured materials used in renewable energy conversion. In this work we present an electrodeposition method in a deep eutectic solvent (DES) to prepare bimetallic high surface area nanostructures of Cu and Au with tunable structure and composition. The metal e...
In this work we present an electrodeposition method in a deep eutectic solvent (DES) to prepare bimetallic high surface area nanostructures of Cu and Au with tunable structure and composition. The metal electrodeposition performed in green choline chloride within a urea deep eutectic solvent allows us to tailor the size, morphology and elemental co...
Controlled electrodeposition and surface nanostructuring are very promising approaches to tailor the structure of the electrocatalyst surface, with the aim to enhance their efficiency for sustainable energy conversion reactions. In this highlight, we first summarise different strategies to modify the structure of the electrode surface at the atomic...
A detailed description of the Cu–electrolyte interface is vital to understand the electrocatalytic properties of Cu surfaces. Herein, we combine cyclic voltammetry and the laser-induced temperature jump technique to describe the structure of the Cu(111) and Cu(100) | electrolyte interfaces in 0.1 M NaOH in a glass-free electrochemical cell. The las...
The purpose of this systematic study was to investigate the effects of specific substrates and potential conditions applied while tailoring the morphology and chemical composition of nanostructured Co films. In particular, Co electrodeposition in sustainable choline chloride-urea deep eutectic solvent was assessed, using glassy carbon and two metal...
Herein, we have investigated the interfacial properties of Cu(111) and Cu(100) in phosphate buffer solutions at different pH conditions and in presence of CO. Ab initio molecular simulations of the Cu-electrolyte interface were combined with voltammetric experiments carried out on Cu(100) and Cu(111) single-crystalline electrodes. We show that the...
The interfacial properties of platinum single crystal electrodes in contact with alkaline aqueous solutions (pH = 13) have been investigated using the laser induced temperature jump method. This technique offers insights into the net orientation of water dipoles in contact with the electrode surface by recording the coulostatic potential changes af...
Aiming to reduce anthropogenic CO2 emissions, there is an urgent demand to develop more efficient and affordable technologies which convert CO2 into valuable feedstock molecules. The use of renewable electricity is a promising and sustainable approach to overcome this environmental issue, while producing valuable chemicals and clean fuels. However,...
The interface between several Room Temperature Ionic Liquids (RTILs) in contact with both Au(hkl) basal planes and Pt(111) was studied by using cyclic voltammetry and Laser Induced Temperature Jump Technique (LITJT). Three RTILs, based on the imidazolium cation and the [Tf 2 N] anion were investigated: [Emmim][Tf 2 N], [Emim][Tf 2 N] and [Bmmim][Tf...
The hydrogen evolution reaction (HER) constitutes one of the most important reactions in electrochemistry due to the value of hydrogen as a vector for energy storage and transport. Therefore, understanding the mechanism of this reaction in relation to its pH-dependence is of crucial importance. While the HER on Pt(111) works efficiently in acid med...
This work proposes a pretreatment strategy of a flame-annealed Pt(111) single crystal ensuring surface ordering and avoiding water surface contamination for experiments in ionic liquid (IL) media. A room temperature ionic liquid (RTIL) and a Deep Eutectic Solvent (DES) representative of two families of ionic liquids were selected as test electrolyt...
Aluminium electrodeposition from ionic liquids (ILs) prepared using a novel structure composed by perfluoro-3-oxa-4,5 dichloro-pentan-sulphonate [CF2ClCFClOCF2SO3⁻] and different cations is presented. The novel anion was designed by Solvay Specialty Polymers with the purpose to confer to the ionic liquids strong hydrophobic properties that facilita...
Here we report on an entirely new kind of bioelectronic device – a conventional biosupercapacitor, which is built from copper containing redox proteins. Prior to biodevice fabrication, detailed spectroelectrochemical studies of the protein, viz. Acidithiobacillus ferrooxidans rusticyanin, in solution and in adsorbed state, were performed, including...
The first steps of nickel electrodeposition in a deep eutectic solvent (DES) are analyzed in detail. Several substrates from glassy carbon to Pt(111) were investigated pointing out the surface sensitivity of the nucleation and growth mechanism. For that, cyclic voltammetry and chronoamperometry, in combination with scanning electron microscopy (SEM...
Studies over the entropy of components forming the electrode/electrolyte interface can give fundamental insights into the properties of electrified interphases. In particular, the potential where the entropy of formation of the double layer is maximal (potential of maximum entropy, PME) is an important parameter for the characterization of electroc...
Hydrogen evolution on platinum is a key reaction for electrocatalysis and sustainable energy storage, yet its pH-dependent kinetics are not fully understood. Here we present a detailed kinetic study of hydrogen adsorption and evolution on Pt(111) in a wide pH range. Electrochemical measurements show that hydrogen adsorption and hydrogen evolution a...
The concepts of total and free charge of platinum single crystal electrodes are revised in this paper, together with the associated concepts of potential of zero total and free charge. Total charges can be measured from CO displacement method. Results on solution of different pH are described. A novel buffer composition is used to attain pH values...
The electrodeposition of copper on a polycrystalline gold electrode and on Au(hkl) single crystals was investigated in a deep eutectic solvent (DES). The DES employed consisted of a mixture of choline chloride and urea (1:2). The Au(hkl)/DES interface was studied using cyclic voltammetry in the capacitive region. The blank voltammograms showed char...
We report the potential-dependent interactions of trimesic acid with Cu surfaces in EtOH. CV experiments and electrochemical surface-enhanced Raman spectroscopy show the presence of an adsorbed trimesic acid layer on Cu at potentials lower than 0 V vs Cu. The BTC coverage increases as the potential increases, reaching a maximum at 0 V. Based on mol...
The laser-induced temperature jump method is used to determine the potential of maximum entropy (pme) of a Pt(111) single crystal electrode in contact with an aqueous solution, in a wide pH range and in the absence of specifically adsorbed anions. For this purpose, buffer solutions composed of a mixture of NaF and HClO4 are used. The results are co...
The nucleation of Ag onto vitreous carbon from aqueous 3 M NaCl or 0.6 M NaClO4 and deep eutectic solvent (DES) 1:2 M mixture of choline chloride:urea solutions containing Ag⁺, has been studied analyzing the chronoamperometric response to single potential steps. From the coordinates of the maxima observed in the current responses, the nucleation fr...
The interface between Au(hkl) basal planes and the ionic liquid 1-Ethyl-2,3-dimethyl imidazolium bis(trifluoromethyl)sulfonil imide was investigated by using both cyclic voltammetry and laser-induced temperature jump. Cyclic voltammetry showed characteristic features, revealing surface sensitive processes at the interfaces Au(hkl)/[Emmim][Tf2N]. Fr...
The interfacial properties of Pt(111) single crystal electrodes have been investigated in the pH range 3<pH<5 in order to obtain information about the acidity of electrosorbed water. Proper experimental conditions are defined to avoid local pH changes while maintaining the absence of specifically adsorbed anions and preserving the cleanliness of th...
This is an in depth study in the knowledge of the nucleation and growth mechanism that governs copper electrodeposition in excess chloride media. In these conditions copper electro-reduction takes place via two well-separated steps, since the Cu(I) intermediate is stabilized through chloride complexation. The process was studied in two media, a dee...
The interface between a Pt(111) electrode and a room temperature ionic liquid, 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, was investigated with the laser-induced temperature jump method. In this technique, the temperature of the interface is suddenly increased by applying short laser pulses. The change of the electrode poten...
The aim of the present work is to study copper electrocrystallization in a Deep Eutectic Solvent (DES) (eutectic mixture of choline chloride and urea 1:2) as electrolyte, paying special attention to the influence of the liquid on the nucleation mechanism. Deposition process was studied from both Cu(II) and Cu(I) solutions. As the DES solvent is chl...
From a study of the electrocatalytic reduction of nitrate on Pt and Rh electrodes over a wide pH range, HNO3 is suggested as the only reducible species in nitrate reduction on Pt, whereas both HNO3 and the nitrate anion are reducible on Rh. Rh is the more active catalyst of the two because it can activate nitrate even if no protons are available in...
The aim of the present work was to study the viability of a deep eutectic solvent (DES) solvent (consisting in a eutectic mixture of 1 choline chloride: 2 urea) as electrolyte for the electrodeposition of silver (I), paying special attention to the influence of the liquid on the mechanism of nucleation process. As this DES solvent is rich in chlori...
