Innovative materials
All scientific publications in Area Science Park
Eco-friendly NaCl glycerol-based deep eutectic electrolyte for high-voltage electrochemical double layer capacitor
Abstract Herein, we propose eco-friendly electrolytes based on sodium chloride as a hydrogen bond acceptor and glycerol as a hydrogen bond donor, as alternatives to toxic, flammable and unsustainable electrolytes commonly used in electrochemical energy storage systems. By means of an in-depth multi-technique investigation, including Raman and FT-FIR spectroscopy, of the formulated electrolytes, we point out the effect of the structuring of the system on the transport and electrochemical properties. The 1 : 10 molar ratio mixture proves to be a deep eutectic solvent (DES), showing good room temperature ionic conductivity (0.186 mS cm−1) and electrochemical stability (≈3 V). When implemented as electrolyte in an activated-carbon electrochemical double layer capacitor, this DES exhibits superior performance compared to mixtures with different molar ratio and those containing ethylene glycol as the hydrogen bond donor, with a high operational voltage (2.6 V), a specific capacitance of 14.1 F g−1, and a remarkable cycling stability. These findings highlight the potential of glycerol-based DESs as alternative electrolytes for sustainable electrochemical energy storage applications. Authors Daniele Motta, Alessandro Damin, Hamideh Darjazi, Stefano Nejrotti, Federica Piccirilli, Giovanni Birarda, Claudia Barolo, Claudio Gerbaldi, Giuseppe Antonio Elia, Matteo Bonomo Journal Green Chemistry Pubblication date 31/03/2025 Consult the pubblication
CO2 and Temperature Induced Switching of a Flexible Metal–Organic Framework with Surface-Mounted Nanoparticles
Abstract Within the material family of metal–organic frameworks (MOFs) the subclass of flexible MOFs (flexMOFs) has attracted great attention, showing structural flexibility as a response to external stimuli such as guest adsorption, temperature, and pressure. Hybrid composites like nanoparticle (NP) loaded flexible MOFs, which stand to potentially combine advantageous properties of both are yet largely unexplored. Here the synthesis of flexMOFs with surface mounted nanoparticles, e. g. NP@Zn2(BME-bdc)2dabco composites (NP = Pt and SiO2 nanoparticles, BME-bdc2− = 2,5-bismethoxyethoxy-1,4-benzenedicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]octane) is reported, studying the impact of nanoparticles on the stimulus-responsiveness of a flexMOF. It is shown that CO2 physisorption triggered flexibility of the MOF is retained and reversible for all NP@flexMOF composites. Additionally, it is observed that NPs stabilize the large pore state of the MOF, slightly increasing and shifting the switching pressure window. This effect is also observed during temperature-induced switching but Pt@flexMOF composites partially lose long-range order during the reversion to their narrow pore state, while attached SiO2 NPs allow for a fully reversible transition. These findings suggest that the total exerted material strain triggering the switching is heavily dependent on NP size and the applied stimulus and that guest-induced switchability can be fully realized in NP@flexMOF hybrid materials. Authors Jan Berger, Stephanie Terruzzi, Hana Bunzen, Filippo Ballerini, Marco Vandone, Marcello Marelli, Luca Braglia, Roland A. Fischer, Valentina Colombo, Gregor Kieslich Journal Small Date 07/01/2025 Consult the paper
Degradation of α-MnO2 in Zn-air battery gas-diffusion electrodes: An investigation based on chemical-state mapping
Abstract Here, we present an integrated ultra-high-vacuum (UHV) apparatus for the growth of complex materials and heterostructures. The specific growth technique is the Pulsed Laser Deposition (PLD) by means of a dual-laser source based on an excimer KrF ultraviolet and solid-state Nd:YAG infra-red lasers. By taking advantage of the two laser sources—both lasers can be independently used within the deposition chambers—a large number of different materials—ranging from oxides to metals, to selenides, and others—can be successfully grown in the form of thin films and heterostructures. All of the samples can be in situ transferred between the deposition chambers and the analysis chambers by using vessels and holders’ manipulators. The apparatus also offers the possibility to transfer samples to remote instrumentation under UHV conditions by means of commercially available UHV-suitcases. The dual-PLD operates for in-house research as well as user facility in combination with the Advanced Photo-electric Effect beamline at the Elettra synchrotron radiation facility in Trieste and allows synchrotron-based photo-emission as well as x-ray absorption experiments on pristine films and heterostructures. Authors Benedetto Bozzini, Alessandro Alleva, Valentina Bonanni, Regina Ciancio, George Kourousias, Francesco Guzzi, Piu Rajak, Alessandra Gianoncelli Journal Electrochimica Acta Date 20/12/2024 Consult the paper
Raman Microscopy Identification of Secondary Spurious Phases in Molten GdSr2RuCu2O8-δ Superconductor for Photonics and Plasmonic Applications
Abstract Plasmonic and Photonics applications of superconducting materials, suggested at first by the necessity to minimize the dissipative losses of conventional metals in the high frequency ranges, are topics of growing interest in Optics. In this perspective, GdSr2RuCu2O8-δ (Gd1212) Rutheno-Cuprate Superconductor presents very promising properties, showing both superconducting and magnetically ordered phases coexisting in the same cell. To investigate its features, the fabrication of macroscopic crystallographically oriented samples is necessary. The use of melt texturing techniques has shown to be among the most effective ways to achieve the best characteristics, although the fabrication of high-quality Gd1212 samples is intrinsically difficult. To reach a better understanding of Gd1212 incongruent melting reaction, a series of bulk samples annealed at temperatures below and above the melting temperature was prepared. Raman Microscopy and Mapping performed on molten and re-solidified samples revealed the presence of different phases, corresponding to those identified in our previous studies. These observations were also confirmed by XRD, TGA-DTA, and SEM+EDS characterisations. Secondary phases formation showed a strong dependence on the temperature of the annealing treatments. Susceptibility and magnetization measurements show both superconducting and magnetic transitions and a contribution of different spurious magnetic phases as suggested by EDS. Authors Marcello Gombos, Stefano Managò, Danilo Zola, Giovanni Carapella, Oreste Tarallo, Vito Mocella, Anna Chiara De Luca, Ivo Rendina, Francesco Ruffo, Pasquale Orgiani, Regina Ciancio Journal Accepted at the Annual Meeting of the Association for Computational Linquistics (ACL), Arxiv preprint: 2402.11655 Date 31/10/2024 Consult the paper
Effects of In-Air Post Deposition Annealing Process on the Oxygen Vacancy Content in Sputtered GDC Thin Films Probed via Operando XAS and Raman Spectroscopy
Abstract We investigate the ionic mobility in room-temperature RF-sputtered gadolinium doped ceria (GDC) thin films grown on industrial solid oxide fuel cell substrates as a function of the air-annealing at 800 and 1000 °C. The combination of X-ray diffraction, X-ray photoelectron spectroscopy, operando X-ray absorption spectroscopy, and Raman spectroscopy allows us to study the different Ce3+/ Ce4+ ratios induced by the post growth annealing procedure, together with the Ce valence changes induced by different gas atmosphere exposure. Our results give evidence of different kinetics as a function of the annealing temperature, with the sample annealed at 800 °C showing marked changes of the Ce oxidation state when exposed to both reducing and oxidizing gas atmospheres at moderate temperature (300 °C), while the Ce valence is weakly affected for the 1000 °C annealed sample. Raman spectra measurements allow us to trace the responses of the investigated samples to different gas atmospheres on the basis of the presence of different Gd–O bond strengths inside the lattice. These findings provide insight into the microscopic origin of the best performances already observed in SOFCs with a sputtered GDC barrier layer annealed at 800 °C and are fundamental to further improve sputtered GDC thin film performance in energy devices. Authors Nunzia Coppola, Sami Ur Rehman, Giovanni Carapella, Luca Braglia, Vincenzo Vaiano, Dario Montinaro, Veronica Granata, Sandeep Kumar Chaluvadi, Pasquale Orgiani, Piero Torelli, Luigi Maritato, Carmela Aruta, Alice Galdi Journal ACS Applied Electronic Materials Date 25/09/2024 Consult the paper
La0.2Sr0.25Ca0.45TiO3 Surface Reactivity with H2: A Combined Operando NEXAFS and Computational Study
Abstract A-site doped SrTiO3 is considered as a promising substitute for traditional anodic metals in solid oxide fuel cells (SOFCs). In this study, we present the reactivity of La0.2Sr0.25Ca0.45TiO3 (LCSTO), La0.2Sr0.7TiO3 (LSTO), and SrTiO3 (STO) toward H2 by operando ambient pressure NEXAFS spectroscopy and theoretical spectra simulation with FDMNES code. The samples were synthesized by MBE (molecular beam epitaxy), hydrothermal, and modified-Pechini routes. We found that the reducibility of the samples depends not only on their stoichiometry but also on the morphology, which is determined by the synthetic method. The results of these experiments give insight into the reducibility of Ti4+ in perovskites as well as the opportunity to further optimize the synthesis of these materials to obtain the best performance for SOFC applications. Authors F. Bassato, S. Mauri, L. Braglia, A. Yu. Petrov, E. Dobovičnik, F. Tavani, A. Tofoni, P. Ferrer, D. Grinter, G. Held, P. D’Angelo, P. Torelli Journal The Journal of Physical Chemistry Letters Date 13/08/2024 Consult the paper
Enhancing Multi-Tip Artifact Detection in STM Images Using Fourier Transform and Vision Transformers
Abstract We address the issue of multi-tip artifacts in Scanning Tunneling Microscopy (STM) images by applying the fast Fourier transform (FFT) as a feature engineering method. We fine-tune various neural network architectures using a synthetic dataset, including Vision Transformers (ViT). The FFT-based preprocessing significantly improves the performance of ViT models compared to using only the grayscale channel. Ablation experiments highlight the optimal conditions for synthetic dataset generation. Unlike traditional methods that are challenging to implement for large datasets and used offline, our method enables on-the-fly classification at scale. Our findings demonstrate the efficacy of combining the Fourier transform with deep learning for enhanced artifact detection in STM images, contributing to more accurate analysis in material science research. Authors Tommaso Rodani, Alessio Ansuini, Alberto Cazzaniga Journal ICML ’24 Workshop ML for Life and Material Science: From Theory to Industry Applications Publication date 17/07/2024 Consult the paper
Operando Soft X-ray Absorption of LaMn1–xCoxO3 Perovskites for CO Oxidation
Abstract We employed operando soft X-ray absorption spectroscopy (XAS) to monitor the changes in the valence states and spin properties of LaMn1–xCoxO3 catalysts subjected to a mixture of CO and O2 at ambient pressure. Guided by simulations based on charge transfer multiplet theory, we quantitatively analyze the Mn and Co 2p XAS as well as the oxygen K-edge XAS spectra during the reaction process. The Mn sites are particularly sensitive to the catalytic reaction, displaying dynamics in their oxidation state. When Co doping is introduced (x ≤ 0.5), Mn oxidizes from Mn2+ to Mn3+ and Mn4+, while Co largely maintains a valence state of Co2+. In the case of LaCoO3, we identify high-spin and low-spin Co3+ species combined with Co2+. Our investigation underscores the importance to consider the spin and valence states of catalyst materials under operando conditions. Authors Qijun Che, Mahnaz Ghiasi, Luca Braglia, Matt LJ Peerlings, Silvia Mauri, Piero Torelli, Petra de Jongh, Frank MF de Groot Journal ACS Catalysis Date 12/07/2024 Consult the paper
Low-Temperature Methane Activation Reaction Pathways over Mechanochemically-Generated Ce4+/Cu+ Interfacial Sites
Abstract Methane is a valuable resource and its valorization is an important challenge in heterogeneous catalysis. Here it is shown that CeO2/CuO composite prepared by ball milling activates methane at a temperature as low as 250 °C. In contrast to conventionally prepared catalysts, the formation of partial oxidation products such as methanol and formaldehyde is also observed. Through an in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and operando Near Edge X-Ray Absorption Fine Structure Spectroscopy (NEXAFS) approach, it can be established that this unusual reactivity can be attributed to the presence of Ce4+/Cu+ interfaces generated through a redox exchange between Ce3+ and Cu2+ atoms facilitated by the mechanical energy supplied during milling. DFT modeling of the electronic properties confirms the existence of a charge transfer mechanism. These results demonstrate the effectiveness and distinctiveness of the mechanical approach in creating unique and resilient interfaces thereby enabling the optimization and refining of CeO2/CuO catalysts in methane activation reactions. Authors Silvia Mauri, Rudy Calligaro, Carlo Federico Pauletti, Matteo Farnesi Camellone, Marta Boaro, Luca Braglia, Stefano Fabris, Simone Piccinin, Piero Torelli, Alessandro Trovarelli Journal Small Date 11/06/2024 Consult the paper
On the origin of the improved hydrogen evolution reaction in Mn-and Co-doped MoS 2
Abstract In the field of hydrogen production, MoS2 demonstrates good catalytic properties for the hydrogen evolution reaction (HER) which improve when doped with metal cations. However, while the role of sulfur atoms as active sites in the HER is largely reported, the role of metal atoms (i.e. molybdenum or the dopant cations) has yet to be studied in depth. To understand the role of the metal dopant, we study MoS2 thin films doped with Co and Mn ions. We identify the contribution of the electronic bands of the Mn and Co dopants to the integral valence band of the material using in situ resonant photoemission measurements. We demonstrate that Mn and Co dopants act differently: Mn doping favors the shift of the S–Mo hybridized band towards the Fermi level, while in the case of Co doping it is the less hybridized Co band that shifts closer to the Fermi level. Doping with Mn increases the effectiveness of S as the active site, thus improving the HER, while doping with Co introduces the metallic site of Co as the active site, which is less effective in improving HER properties. We therefore clarify the role of the dopant cation in the electronic structure determining the active site for hydrogen adsorption/desorption. Our results pave the way for the design of efficient materials for hydrogen production via the doping route, which can be extended to different catalytic reactions in the field of energy applications. Authors Pasquale Orgiani, Luca Braglia, Vincent Polewczyk, Zhiwei Nie, Francesco Lavini, Shyni Punathum Chalil, Sandeep Kumar Chaluvadi, Piu Rajak, Floriana Morabito, Edvard Dobovičnik, Vittorio Foglietti, Piero Torelli, Elisa Riedo, Regina Ciancio, Nan Yang, Carmela Aruta Journal Nanoscale Date 25/05/2024 Consult the ppaer
Advanced Electrode Materials Based on Brownmillerite Calcium Ferrite for Li-Ion Batteries
Abstract Iron-based materials are considered potential anode materials for lithium-ion batteries thanks to their low cost, abundancy, non-flammability, good safety, environmental benignity, and high specific capacity. Here, a series of calcium iron oxides materials having brownmillerite structure (i. e., Ca2Fe2-xMxO5, where M=Mn, Ni and Cu and x=0 and 0.1) has been extensively studied for their use as conversion anodes in lithium cell. In particular, a mechanochemical approach has been used either to synthesize the samples and to prepare electrodes for the tests in lithium cell. Ca2Fe2O5 based electrodes proved excellent performance in lithium cell, approaching the theoretical capacity and being stable upon prolonged cycling (529 mAh g−1 at C/10 and a capacity retention of 81 % after 100 cycles). Through the use of ex-situ diffraction measurements, we have analyzed the conversion mechanism and proved the partial reversibility of its electrochemical reaction. Also, the incorporation of dopants into the structure of calcium iron oxide resulted in further improvement of its electrochemical performance as is the case of Mn doped sample that show a considerable specific capacity of 567 mAh g−1 and the capacity retention is almost 99 % after 100 cycles. Authors Guido Spanu, Arcangelo Celeste, Francesco Bozza, Emanuele Serra, Piero Torelli, Luca Braglia, Sergio Brutti, Priscilla Reale, Laura Silvestri Journal Batteries & Supercaps Date 18/05/2024 Consult the paper
Pulsed Laser Deposition using high-power Nd:YAG laser source operating at its first harmonics: recent approaches and advances
Abstract We report on the progress of Pulsed Laser Deposition growth of thin films by using a high-power Nd:YAG laser source. We demonstrate that by using the fundamental wavelength at 1064 nm, the congruent ablation of a large number of materials can be successfully achieved. Even if the infra-red radiation of the fundamental harmonics of Nd:YAG lasers – corresponding to impinging photons with energy of about 1.16 eV – is unexpectedly proved to be also absorbed by insulating materials characterized by a large value of the band-gap (e.g. 3.0 eV for rutile TiO2). Combined investigation of structural properties by transmission electron microscopy and scanning electron microscopy provides evidence of the very high-quality thin films grown by Nd:YAG lasers with no trace of precipitates and droplets over a scale of tens of micrometers. Authors S. K. Chaluvadi, S. Punathum Chalil, F. Mazzola, P. Rajak, P. Banerjee, D. Knez, R. Ciancio, G. Rossi, P. Orgiani Journal Proceedings of SPIE – The International Society for Optical Engineering Date 11/04/2024 Consult the paper