Description
The Functional Nanomaterials Group designs and engineers nanomaterials with optimized functionalities and applies them in energy conversion, energy storage and environmental remediation technologies.
Our efforts are mainly focused on the synthesis of colloidal nanoparticles, and their assembly and use in different energy conversion technologies. In particular, we have pioneered strategies to produce complex multinary chalcogenides, phosphides and oxides and on their application in thermoelectric energy conversion, Li-S batteries and electrocatalysis.
A major outcome of our work has been the production of bulk materials with world record ZT values, which would allow up to 60% higher energy conversion efficiencies than current commercial devices. We have also developed innovative techniques to manipulate the surface chemistry of colloidal nanocrystals and assemble them into clusters, thin films, gels and bulk nanocomposites.
Our laboratories are equipped with the all the necessary set-ups to undertake every stage in the development of nanomaterial-based energy conversion devices, including nanomaterials synthesis, manipulation and fabrication of macroscopic structures and devices, material functional characterization and device test.
The laboratory equipment photos of Functional Nanomaterials research group are available in Multimedia Gallery.
<strong>SYNTHESIS</strong>
• Colloidal nanocrystals and quantum dots
• Nanowires, nanotubes
• 2D materials
• Magnetic nanoparticles
• Reactive inks
• Thin films
PROCESSING
• Surface functionalization
• Nanoparticle assembly, composites
• Textured nanomaterials
• Nanoparticle-based inks and gels
• Supercritical drying
• Rapid hot press
• High resolution rapid 3D printing
APPLICATIONS
• Thermoelectrics
• Fuel cells
• Li-S and metal-air batteries
• (Electro-, photo-) catalysis
• Fuel synthesis
• Environmental remediation
• Functional coatings
People
Projects
Here is a selection of the group’s competitive European and national projects. For the full list of projects that the group is involved in, click the “View all projects” button.
COMBENERGY
GELTHERM
SEHTOP-NP
Innov_3DPrint
Tech Transfer
Thermoelectric nanomaterials and printed devices: We have recently produced thermoelectric devices with record figures of merit at ambient temperatures using nanocrystals building blocks and a new consolidation strategy that has allowed the production of crystallographically textured samples. We are currently engineering thermoelectric devices using printing strategies.
Synthesis of nanomaterials: Development of novel processes for the growth of nanocrystals and nanoheterostructures using colloidal strategies, hydrothermal, chemical vapor deposition, electrodeposition, etc. We achieve control over size, shape, composition and crystallographic phase of nanocrystals providing a correlation between those parameters, the functional properties of the material and their performance in real application such as energy storage, thermoelectricity, CO2 conversion, and water remediation. Furthermore, the synthesis of nanoheterostructures provides the combination of different features in one single platform while designing the nanocrystal-interphase provides control over novel features and performance, particularly in advanced catalysis reactions.
Assembly of nanocrystals into hierarchical suprastructures: Design novel assembly routes to produce multifunctional suprastructures out of inorganic and organic nanoscale building blocks. Electrostatic, solvophobic or molecular interactions are exploited to achieve control over the structure: from densely packed supercrystals to mesoporous aerogles. Our developed assembly routes provide us control over the building block size, distribution and interaction along the supercrystal or aerogel. As such, we are able to design smart nanostructured platforms for water remediation, catalysis, energy storage and sensing applications.
Rapid 3D printing: We have demonstrated the possibility of moving a jet with accelerations above 500,000 m/s2 and speeds close to 10 m/s using electrostatic fields. We are using this concept to develop a new 3D printing technology that makes use of electrostatic fields to deflect the material jet and thus control the positioning of the added material. The use of a fast positioning will allow us to further increase the jet generation speed to 1-10 m/s. We are validating this new and revolutionary technological concept, which will allow printing speeds more than 100 times faster than current technologies based on material jetting. At the same time, the use of charged jets will potentially allow us to create filaments with a thickness down to 100 nm, thus potentially providing sub-micrometer resolution. This technology will be initially based on inks, capable of creating 3D structures of any composition, including metals, semiconductors, oxides, and even proteins and biological material. With the possibility of fabricating 3D structures with submicron resolution at high speed and with an unlimited material versatility, comes the opportunity to advantageously compete in a number of fields which conventional additive technologies have already entered, while also opening new blue ocean markets for 3D printing strategies.
Model catalytic materials: In recent years, our group has been exploiting the large portfolio of nanomaterial and hierarchical suprastructures produced for its exploitation in several key-reactions in the area of energy conversion and storage.
Publications
Here are summaries of some of the group’s recent publications. For a full list of the group’s publications, click the “View all publications” button.
Phosphorous incorporation in Pd2Sn alloys for electrocatalytic ethanol oxidation
Nano Energy Volume 77. Elsevier. Publication: November 2020, 105116. Available online 19 July 2020 https://doi.org/10.1016/j.nanoen.2020.105116
Direct ethanol fuel cells (DEFCs) show a huge potential to power future electric vehicles and portable electronics, but their deployment is currently limited by the unavailability of proper electrocatalysis for the ethanol oxidation reaction (EOR). In this work, we engineer a new electrocatalyst by incorporating phosphorous into a palladium-tin alloy and demonstrate a significant performance improvement toward EOR. We first detail a synthetic method to produce Pd2Sn:P nanocrystals that incorporate 35% of phosphorus. These nanoparticles are supported on carbon black and tested for EOR. Pd2Sn:P/C catalysts exhibit mass current densities up to 5.03 A mgPd−1, well above those of Pd2Sn/C, PdP2/C and Pd/C reference catalysts. Furthermore, a twofold lower Tafel slope and a much longer durability are revealed for the Pd2Sn:P/C catalyst compared with Pd/C. The performance improvement is rationalized with the aid of density functional theory (DFT) calculations considering different phosphorous chemical environments. Depending on its oxidation state, surface phosphorus introduces sites with low energy OH− adsorption and/or strongly influences the electronic structure of palladium and tin to facilitate the oxidation of the acetyl to acetic acid, which is considered the EOR rate limiting step. DFT calculations also points out that the durability improvement of Pd2Sn:P/C catalyst is associated to the promotion of OH adsorption that accelerates the oxidation of intermediate poisoning COads, reactivating the catalyst surface.
Selective Methanol‐to‐Formate Electrocatalytic Conversion on Branched Nickel Carbide
Wiley Online Library. Angewandte Chemi. Publication: August 6, 2020 https://doi.org/10.1002/ange.202004301
Highly active Ni3C branched particles are demonstrated and their selective electrocatalytic conversion of methanol to formate is probed by using advanced in situ infrared spectroscopy combined with nuclear magnetic resonance spectroscopy.
A methanol economy will be favored by the availability of low‐cost catalysts able to selectively oxidize methanol to formate. This selective oxidation would allow extraction of the largest part of the fuel energy while concurrently producing a chemical with even higher commercial value than the fuel itself. Herein, we present a highly active methanol electrooxidation catalyst based on abundant elements and with an optimized structure to simultaneously maximize interaction with the electrolyte and mobility of charge carriers. In situ infrared spectroscopy combined with nuclear magnetic resonance spectroscopy showed that branched nickel carbide particles are the first catalyst determined to have nearly 100 % electrochemical conversion of methanol to formate without generating detectable CO2 as a byproduct. Electrochemical kinetics analysis revealed the optimized reaction conditions and the electrode delivered excellent activities. This work provides a straightforward and cost‐efficient way for the conversion of organic small molecules and the first direct evidence of a selective formate reaction pathway.
SnS2/g-C3N4/graphite nanocomposites as durable lithium-ion battery anode with high pseudocapacitance contribution
Electrochimica Acta. Elsevier.Publication: July 20, 2020 https://doi.org/10.1016/j.electacta.2020.136369
Tin disulfide is a promising anode material for Li-ion batteries (LIB) owing to its high theoretical capacity and the abundance of its composing elements. However, bare SnS2 suffers from low electrical conductivity and large volume expansion, which results in poor rate performance and cycling stability. Herein, we present a solution-based strategy to grow SnS2 nanostructures within a matrix of porous g-C3N4 (CN) and high electrical conductivity graphite plates (GPs). We test the resulting nanocomposite as anode in LIBs. First, SnS2 nanostructures with different geometries are tested, to find out that thin SnS2 nanoplates (SnS2-NPLs) provide the highest performances. Such SnS2-NPLs, incorporated into hierarchical SnS2/CN/GP nanocomposites, display excellent rate capabilities (536.5 mA h g−1 at 2.0 A g−1) and an outstanding stability (∼99.7% retention after 400 cycles), which are partially associated with a high pseudocapacitance contribution (88.8% at 1.0 mV s−1). The excellent electrochemical properties of these nanocomposites are ascribed to the synergy created between the three nanocomposite components: i) thin SnS2-NPLs provide a large surface for rapid Li-ion intercalation and a proper geometry to stand volume expansions during lithiation/delithiation cycles; ii) porous CN prevents SnS2-NPLs aggregation, habilitates efficient channels for Li-ion diffusion and buffer stresses associated to SnS2 volume changes; and iii) conductive GPs allow an efficient charge transport.
Self-Induced Strain in 2D Chalcogenide Nanocrystals with Enhanced Photoelectrochemical Responsivity
Chem. Mater. 2020, 32, 7, 2774–2781 Publication: March 5, 2020. https://doi.org/10.1021/acs.chemmater.9b04182
Strain engineering has become an emerging strategy to tailor the performance of nanocatalysts. However, current strained catalysts overwhelmingly rely on stresses originated at catalyst–support interfaces. Self-standing strained nanostructures are extremely challenging to produce, and thus their impact on catalytic and photocatalytic activities remains largely unknown. Herein, we propose a ligand-based colloidal strategy for the one-step growth of bended metal chalcogenide nanoplates with a built-up strain. This strategy is based on the seeded growth of strained nanostructures from sacrificial seeds which provide a proper lattice mismatch. We demonstrate this strategy for the synthesis of strained orthorhombic SnSe and SnS nanoplates from rock salt SnS seeds. We probe not only the presence of atomic distortions in the periodic lattice but also its coupling with the generation of a large density of selenium vacancies. Geometrical phase analysis evidences the formation of a strain field in self-bended SnSe nanoplates, with a maximum tensile strain up to 12%. Theoretical and experimental results further reveal that the strain-related selenium vacancies strongly affect the electronic structure of SnSe and facilitate the mobility of photogenerated charge carriers, which result in a significantly improved photoelectrochemical activity. The strategy presented here opens a new avenue for precisely tuning semiconductor functionalities via strain engineering.
A SnS2 Molecular Precursor for Conformal Nanostructured Coatings
We present a simple, versatile, and scalable procedure to produce SnS2 nanostructured layers based on an amine/thiol-based molecular ink. The ratios amine/thiol and Sn/S, and the reaction conditions, are systematically investigated to produce phase-pure SnS2 planar and conformal layers with a tremella-like SnS2 morphology. Such nanostructured layers are characterized by excellent photocurrent densities. The same strategy can be used to produce SnS2–graphene composites by simply introducing graphene oxide (GO) into the initial solution. Conveniently, the solvent mixture is able to simultaneously dissolve the Sn and Se powders and reduce the GO. Furthermore, SnS2-xSex ternary coatings and phase-pure SnSe2 can be easily produced by simply incorporating proper amounts of Se into the initial ink formulation. Finally, the potential of this precursor ink to produce gram-scale amounts of unsupported SnS2 is investigated.
Stability of Pd3Pb Nanocubes during Electrocatalytic Ethanol Oxidation
Chem. Mater. 2020, 32, 5, 2044–2052. Publication: February 7, 2020 . https://doi.org/10.1021/acs.chemmater.9b05094
Intermetallic Pd3Pb nanocrystals with controlled size and cubic geometry exposing (100) facets are synthesized and tested as electrocatalysts for ethanol oxidation in alkaline media. We observe the ethanol oxidation activity and stability to be size-dependent. The 10 nm Pd3Pb nanocrystals display the highest initial current densities, but after few hundred cycles, the current density of smaller nanocrystals becomes much larger. All of the catalysts exhibit a pronounced current decay during the first 500 s of continuous operation, which is associated with the accumulation of strongly adsorbed reaction intermediates, blocking reaction sites. These adsorbed species can be removed by cycling the catalysts or maintaining them at slightly higher potentials for a short period of time to oxidize and later reduce the Pd surface. Such simple cleaning processes, that can be performed during operation breaks without cell disassembly, is sufficient to effectively remove the poisoning species adsorbed on the surface and recover the electrocatalytic activity.
Theses
PRESENTED PhD THESES
2019
PhD graduate: Junfeng Liu
PhD supervisor: A. Cabot, M. Menys
Title: Colloidal Metal Phosphide Nanocrystals for Electrochemical Energy Technologies
Presented date: 01/10/2019
PhD graduate: Junshan Li
PhD supervisor: Dr. Andreu Cabot
Title: Ni-Co-Sn Colloidal Nanoparticles for Electrochemical Energy Technologies
Presented date: 18/06/2019
2018
PhD graduate: Yu Liu
PhD supervisor: A. Cabot, D. Cadavid
Title: Bottom-up Engineering of Chalcogenide Thermoelectric Nanomaterials
Presented date: 12/07/2018
PhD graduate: Taisiia Berestok
PhD supervisor: A. Cabot, F. Peiró
Title: Assembly of colloidal nanocrystals into porous nanomaterials
Presented date: 13/07/2018
2017
PhD graduate: Silvia Ortega Torres
PhD supervisor: Dr. Andreu Cabot
Title: Devices from the bottom-up assembly of nanoheterostructures
Presented date: 20/07/2017
2016
PhD graduate: Zhishan Luo
PhD supervisor: Dr. Andreu Cabot, Dr. Maria Ibáñez
Title: Compositional Engineering of Colloidal Nanoparticles for Energy Conversion
Presented date: 19/12/2016
2015
PhD graduate: Àlex Carreté Bello
PhD supervisor: Dr. Andreu Cabot
Title: Solution-processed solar cell devices
Presented date: 29/05/2015
2014
PhD graduate: Doris Yaneth Cadavid
PhD supervisor: Dr. Andreu Cabot
Title: Towards high performance nanostructures thermoelectric materials
Presented date: 12/03/2014
PhD graduate: Raquel Nafria
PhD supervisor: Prof. Dr. Andreu Cabot
Title: Síntesi i caracterització de nanopartícules mono- i bimetàl∙liques per aplicacions catalítiques
Presented date: 12/12/2014
2013
PhD graduate: Maria Ibáñez Sabaté
PhD supervisor: Dr. Andreu Cabot; Dr. Joan Ramon Morante
Title: Functional Nanomaterials from the Bottom-up Assembly of Colloidal Nanoparticles. A Strategy Towards Efficient Thermoelectrics
Presented date: 05/03/2013
PhD graduate: Jiandong Fan
PhD supervisor: Dr. Andreu Cabot
Title: Solution growth and functional properties of vertically aligned ZnO nanowires
Presented date: 17/09/2013
PhD graduate: Wenhua Li
PhD supervisor: Dr. Andreu Cabot
Title: Shape control and functional properties of copper chalcogenide colloidal nanocrystals
Presented date: 01/10/2013
Facilities
Our laboratories are equipped with state-of-the-art technologies for the synthesis, manipulation and characterization of functional materials, the fabrication of energy conversion and storage devices and the evaluation of their performance. Specifically, our laboratories allow us to perform the following:
- Nanoparticle synthesis (2-glove glovebox, 8 fume hoods with colloidal synthesis set-ups, hydrothermal synthesis, ball milling)
- Photo- / electro.- catalytic properties analysis (gas chromatography, potentiostats, solar-simulator, catalytic reactors up to 400 ºC)
- Nanomaterial/nanocomposite preparation (16-glove gloveboxes, rapid hot press, tubular furnaces, induction ovens, vacuum infusion)
- Nanomaterial growth (dip coating, sputtering, chemical vapor deposition, evaporation)
- Surface functionalization (UV-vis spectroscopy, dynamic light scattering, zeta potential)
- Aerogel preparation (freeze drier, CO2 and high temperature supercritical point driers)
- Ink-based high resolution 3D printing system
- Thermal conductivity analysis, Seebeck coefficient and electrical conductivity analysis up to 600 ºC
- Battery/fuel cell analysis systems
Collaborations
The Functional Nanomaterials group collaborates with several national and international groups in the fields of nanomaterials synthesis and characterization, 3D printing, electro/photo-catalysis, solar energy conversion, thermoelectricity and energy storage:
Thermoelectrics:
- IST Austria
- Universidad Nacional de Colombia
- Universidade Estadual de Campinas Paul Dalton
- Universitat Jaume I
Nanomaterials synthesis and characterization:
- Universita di Cagliari
- CEA Grenoble
- Universitat Politecnica de Catalunya
- Catalan Institute of Nanoscience and Nanotechnology
- Universitat Rovira I Virgili
- Southern University of Science and Technology
- University of Electronic Science and Technology of China
- Jiangsu University
- Beijing Normal University
Solar energy:
- Heilongjiang University
- Institute of New Energy Technology
Catalysis:
- EPFL
- Universitat Rovira I Virgili
- Instituto de Catálisis y Petroleoquímica – CSIC
- Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes
3D printing:
- Universtitat Rovira I Virgili
- University of Würzburg
