IN PRESS - Selected, just-accepted articles

  Universal Fabrication of Highly Efficient Plasmonic Thin-Films for Label-Free SERS Detection

Sara Gullace, Verónica Montes-García, Victor Martín, David Larios, Valentina Girelli Consolaro, Fernando Obelleiro, Giuseppe Calogero, Stefano Casalini, and Paolo Samorì

Journal: Small

IF=13.281

DOI: 0.1002/smll.202100755

The development of novel, highly efficient, reliable, and robust surface enhanced Raman scattering (SERS) substrates containing a large number of hot spots with programmed size, geometry, and density is extremely interesting since it allows the sensing of numerous (bio-)chemical species.
Herein, an extremely reliable, easy to fabricate, and label-free SERS sensing platform based on metal nanoparticles (NPs) thin-film is developed by the layer-by-layer growth mediated by polyelectrolytes. A systematic study of the effect of NP composition and size, as well as the number of deposition steps on the substrate’s performance, is accomplished by monitoring the SERS enhancement of 1-naphtalenethiol (532 nm excitation). Distinct evidence of the key role played by the interlayer (poly(diallyldimethylammonium chloride) (PDDA) or PDDA-functionalized graphene oxide (GO@PDDA)) on the overall SERS efficiency of the plasmonic platforms is provided, revealing in the latter the formation of more uniform hot spots by regulating the interparticle distances to 5 ± 1 nm. The SERS platform efficiency is demonstrated via its high analytical enhancement factor (≈106) and the detection of a prototypical
substance(tamoxifen), both in Milli-Q water and in a real matrix, viz. tap water, opening perspectives towards the use of plasmonic platforms for future high-performance sensing applications.

  Dielectric barrier discharge (DBD) plasma coating of sulfur for mitigation of capacity fade in lithium-sulfur batteries

A. Shafique, V. Shankar Rangasamy, A. Vanhulsel, M. Safari, S. Gross, P. Adriaensens, M. K. Van Bael, A. Hardy, S. Sallard

Article in press in ACS Applied Materials & Interfaces

I. F.: 8.758 (2019)

Sulfur particles with a conductive polymer coating of poly(3,4-ethylene dioxythiophene) “PEDOT” were prepared by dielectric barrier discharge (DBD) plasma technology under atmospheric conditions (low temperature, ambient pressure). We report a solvent free, low cost, low energy consumption, safe, and low risk process to make the material development and production compatible for sustainable technologies. Different coating protocols were developed to produce PEDOT-coated sulfur powders with electrical conductivity in the range of 10-8 - 10-5 S/cm. The raw sulfur powder (used as reference) and (low-, optimum-, high-) PEDOT-coated sulfur powders were used to assemble lithium-sulfur (Li-S) cells with high sulfur loading of ~ 4.5 mg/cm2. Long-term galvanostatic cycling at C/10 for 100 cycles showed that the capacity fade was mitigated by ~ 30% for the cells containing the optimum-PEDOT coated sulfur in comparison to the references Li-S cells with raw sulfur. Rate capability, cyclic voltammetry, and electrochemical impedance analyses confirmed the improved behavior of the PEDOT coated sulfur as an active material for lithium-sulfur batteries. The Li-S cells containing optimum-PEDOT coated sulfur showed the highest reproducibility of their electrochemical properties. A wide variety of bulk and surface characterization methods including conductivity analysis, X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance spectroscopy (NMR) were used to explain the chemical features and the superior behaviour of Li-S cells using the optimum-PEDOT coated sulfur material. Moreover, post-mortem (SEM and BET) analyses of uncoated and coated samples allow us to exclude any significant effect at electrode scale even after 70 cycles.

  Understanding Oxygen Release from Nanoporous Perovskite Oxides and Its Effect on the Catalytic Oxidation of CH4 and CO

E. Poffe, H. Kaper, B. Ehrhardt, L. Gigli, D. Aubert, L. Nodari, S. Gross and S. Mascotto

Article in press in ACS Applied Materials & Interfaces

I. F.: 8.758 (2019)

The design of nanoporous perovskite oxides is considered an efficient strategy to develop performing, sustainable catalysts for the conversion of methane. The dependency of nanoporosity on the oxygen defect chemistry and the catalytic activity of perovskite oxides towards CH4 and CO oxidation was here studied. A novel colloidal synthesis route for nanoporous, hightemperature stable SrTi0.65Fe0.35O3-δ with specific surface area (SSA) ranging from 45 to 80 m2 /g and pores from 10 to 100 nm was developed. High-temperature investigations by in situ synchrotron XRD and TG-MS combined with H2-TPR and Mössbauer spectroscopy showed that the porosity improved the release of surface oxygen and the oxygen diffusion, whereas the release of lattice oxygen depended more on the state of the iron species and strain effects in the materials. Regarding catalysis, light-off tests showed that low-temperature CO oxidation significantly benefitted from the enhancement of the SSA, whereas high-temperature CH4 oxidation is influenced more from the dioxygen release. During isothermal long-term catalysis tests however the continuous oxygen release from large SSA materials promoted both CO and CH4 conversion. Hence, if SSA maximization turned out to efficiently improve low-temperature and long-term catalysis applications, the role of both reducible metal center concentration and crystal structure cannot be completely ignored, as they also contribute to the perovskite oxygen release properties.

  Opportunities from doping of non-critical metal oxides in last generation light-conversion devices

Teresa Gatti, Francesco Lamberti, Raffaello Mazzaro, Ilka Kriegel, Derck Schlettwein, Francesco Enrichi, Nicolò Lago, Eleonora Di Maria, Gaudenzio Meneghesso, Alberto Vomiero, Silvia Gross

Adv. Energy Mater., Just Accepted Manuscript

DOI: 10.1002/aenm.202101041

I. F.: 25.2

The need to develop sustainable energy solutions is an urgency for our societies, with the additional stringent requirement to limit dependence on critical raw materials and to implement a virtuous circular economy model. In this framework, it is essential to identify new avenues for light-conversion into clean energy and fuels exploiting largely available materials and green production methods. Metal oxide semiconductors (MOSs) emerge among other species for their remarkable environmental, thermal and chemical stability, wide chemical tunability, and interesting optoelectronic properties. MOSs are often key constituents in next generation energy devices, mainly with the role of charge selective layers. Their use as light harvesters is hitherto rather limited, but progressively emerging. One of the key strategies to boost and tailor their properties resorts to doping, that can improve charge mobility, light absorption and can tune band structures to maximize charge carrier separation at heterojunctions. In this perspective, we identify and critically compare effective methods to dope MOSs and to exploit the deriving benefits in relation to performance enhancement in different types of light-conversion devices. We focus specifically on the best opportunities coming from the use of non-critical raw materials, so as to contribute in defining an economically feasible roadmap for light energy conversion technologies based on these highly stable and largely available compounds.

  Enabling circular economy: the overlooked role of inorganic materials chemistry

Gabriella Salviulo, Maria Cristina Lavagnolo, Manuele Dabalà, Enrico Bernardo, Antonino Polimeno, Mauro Sambi, Franco Bonollo and Silvia Gross

Invited Essay, Chemistry A European Journal, 2021, 27, 1-21

DOI: 10.1002/chem.202002844

Circular economy, acknowledged as “an opportunity to rethink our economic future”, is considered a new chance to build a more sustainable world from both the social and the economic point of views. Europe and European member states are resolutely moving toward a circular paradigm in goods design and production, a scenario which requires a robust technical and scientific background, where chemistry is expected to play a major role. The pivotal role of chemistry in supporting and fostering this implementation has been exemplarily outlined in three very recent papers as well as in technical reports focusing on the contribution of chemistry to consolidate the assets of the chemical industry towards the circular economy model. In this Essay paper, by adopting a truly interdisciplinary approach, encompassing expertise in inorganic materials chemistry, modelling, materials engineering, circular waste management, metallurgy, mineralogy, we outline the possible contribution of inorganic chemistry towards a smooth transition to circularity in inorganic materials design and production, to enable them to enter into the circular loop. A further aim of this contribution is also to contextualise these efforts within a coherent and holistic framework provided by the policies of the European Commission, entailing also sizable regulatory initiatives, and by a worldwide leaning toward a more sustainable development.

  Large cation engineering in two-dimensional silver-bismuth bromide double perovskites

Fabian Schmitz, Jonas Horn, Nicola Dengo, Alexander E. Sedykh, Jonathan Becker, Elena Maiworm, Péter Bélteky, Ákos Kukovecz, Silvia Gross, Francesco Lamberti, Klaus Müller-Buschbaum, Derck Schlettwein, Daniele Meggiolaro, Marcello Righetto, Teresa Gatti

Chem. Mater.., Just Accepted Manuscript

https://doi.org/10.1021/acs.chemmater.1c01182

I. F.: 9.6

Double perovskites are promising candidates for less toxic and highly stable metal halide perovskites, but their optoelectronic performances still lag behind those of the lead halide counterpart, due to the indirect nature of the bandgap and the strong electron-phonon coupling. Reducing the dimensionality of Cs2AgBiBr6 down to a 2D layered form is strategic in order to tune the band gap from indirect to direct and provides new insights into the structure-property relationships of double perovskites. Herein, we report on a series of monolayer 2D hybrid double perovskites of formula (RA)4AgBiBr8, where RA represents different primary ammonium large cations with alkyl- and aryl-based functionalities. An in-depth experimental characterization of structure, film morphology and optical properties of these perovskites is carried out. Interestingly, the variation of the ammonium cation and the inter-planar distance between adjacent inorganic monolayers has peculiar effects on the film-forming ability and light emission properties of the perovskites. Experiments have been combined with DFT calculations in order to understand the possible origin of the different emissive features. Our study provides a toolbox for future rational developments of 2D double perovskites, with the aim of narrowing the gap with lead halide perovskite optoelectronic properties.

  Hybridization of Molecular and Graphene Materials for CO2 Photocatalytic Reduction with Selectivity Control

Bing Ma, Matias Blanco, Laura Calvillo, Lingijing Chen, Gui Chen, Tai-Chu Lau, Goran Drazic, Julien Bonin, Marc Robert and Gaetano Granozzi

J. Am. Che. Soc.   2021

IF: 14.612

DOI: 10.1021/jacs.1c02250

In the quest for designing efficient and stable photocatalytic materials for CO2 reduction, hybridizing a selective noble-metal-free molecular catalyst and carbon-based light-absorbing materials has recently emerged as a fruitful approach. In this work, we report about Co quaterpyridine complexes covalently linked to graphene surfaces functionalized by carboxylic acid groups.  The nanostructured materials were characterized by X-ray photoemission spectroscopy, X-ray absorption spectroscopy, IR and Raman spectroscopies, and high-resolution transmission electron microscopy and proved to be highly active in the visible-light-driven CO2 catalytic conversion in acetonitrile solutions. Exceptional stabilities (over 200 h of irradiation) were obtained without compromising the selective conversion of CO2 to products (>97%). Most importantly, complete selectivity control could be obtained upon adjusting the experimental conditions: production of CO as the only product was achieved when using a weak acid (phenol or trifluoroethanol) as a co-substrate, while formate was exclusively obtained in solutions of mixed acetonitrile and triethanolamine.

  Selective and scaled-up continuous flow synthesis of manganese oxide nanocatalysts for single electron transfer reactions

Dario Mosconi, Matías Blanco, JiaJia Ran, Marco Sturaro, Marco Bersani, Gaetano Granozzi

Chem. Eng. J.    2021

IF: 10.652

DOI: 10.1016/j.cej.2021.129063

The application of high-quality nanomaterials in industrial products and processes is somewhat hindered by their actual market availability at a large scale, mostly due to preparation methods which can be hardly scalable for cost, reproducibility, sustainability or complexity issues. Herein, the application of the Continuous Flow Hydrothermal Synthesis (CFHS) is presented to prepare various nano Mn oxides in supercritical water with common and low-cost precursors and additives, yielding an outstanding production rate of 1 Kg day-1. Since Mn oxidation state spans from MnII to MnVII, the implemented process generates, with exquisite selectivity and consistency, nanosized MnO, α-MnO2, β-MnO2, λ-MnO2, Mn2O3, Mn3O4 and LiMn2O4 oxides with reproducible characteristics of the obtained phase under controlled synthetic conditions. As a case study, all our MnOx nanomaterials were tested as catalyst precursors in the Single Electron Transfer (SET) oxidation of olefins with 1,3-dicarbonyl compounds, obtaining recyclable active materials whose respective activity depends on the particular oxide structure, therefore proving the importance of phase selectivity in the final application.

  Multimodal hybrid 2D networks via the thiol-epoxide reaction on 1T/2H MoS2 polytypes

Giulia Tuci, Andrea Rossin, Cuong Pham-Huu, Dario Mosconi, Lapo Luconi, Stefano Agnoli, Gaetano Granozzi and Giuliano Giambastiani

Mater. Chem. Front., 2021

IF: 6.788

DOI: 10.1039/d1qm00003a

Searching for new protocols aimed at the surface functionalization of TMDCs is the password for filling the gap between reactivity and versatility of 2D carbon-based networks and their inorganic counterparts.
This contribution describes a straightforward but effective approach to the chemical decoration of chemically exfoliated MoS2 nanosheets with -hydroxyl organic pendant arms. The adopted strategy is based on the thiol-epoxide ‘‘click’’ reaction and generates functional hybrids with a loading of dangling organic groups directly proportional to the epoxide electrophilic character. Most importantly, this grafted methodology occurs for the first time on both phases (1T and 2H) of the model  chalcogenide and provides functional samples suitable for an additional functionalization step-forward (post-derivatization).

  Light-mediated control of activity in a photosensitive foldamer that mimics an esterase

Matteo Pollastrini, Giulia Marafon, Jonathan Clayden and Alessandro Moretto

Chemical Communications

IF: 6.050

https://doi.org/10.1039/D0CC08309G (2021)

We report a catalytic foldamer in which a fumaramide chromophore links a Ser residue to a helical domain that contains within its sequence the residues His and Asp. Photoisomerization of the fumaramide chromophore (with E geometry) to the corresponding maleamide (with Z geometry) brings together a ‘catalytic triad’ of Ser, His, and Asp, triggering esterase activity that is absent in the fumaramide isomer. The fumaramide/maleamide linker thus acts as a light-sensitive switchable cofactor for activation of catalytic activity in short foldamers.

  Photoresponsive Prion-Mimic Foldamer to Induce Controlled Protein Aggregation

Giulia Marafon, Marco Crisma, Anna Masato, Nicoletta Plotegher,Luigi Bubacco, Alessandro Moretto

12 November 2020  https://doi.org/10.1002/anie.202012995

 Angewandte Chemie International Edition

 Impact Factor 12.95

Proteins reconfigure their 3D-structure, and consequently their function, under the control of specific molecular interactions that sense, process and transmit information from the surrounding environment. When this fundamental process is hampered, many pathologies occur as in the case of protein misfolding diseases. In this work, we follow the early steps of α-synuclein (aS) aggregation, a process associated with Parkinson’s disease etiopathogenesis, that is promptly promoted by a light-mediated binding between the protein and a photoactive foldamer. The latter can switch between two conformations, one of which generates supramolecular fibrillar seeds that act as molecular templates able to induce a fast β-sheet transition for aS monomers that successively undergo fibrillar polymerization. The proposed method represents a powerful tool to study protein aggregation relevant to misfolding diseases in a controlled and inducible system.

  Harnessing Selectivity and Sensitivity in Ion Sensing via Supramolecular Recognition: A 3D Hybrid Gold Nanoparticle Network Chemiresistor

Verónica Montes-García, Rafael Furlan de Oliveira, Ye Wang, Andrey Berezin, Pablo Fanjul-Bolado, María Begoña González García, Thomas M. Hermans, Davide Bonifazi, Stefano Casalini, and Paolo Samorì

Advanced Functional Materials

Impact Factor of the Journal:

IF=16.836

DOI: 10.1002/adfm.202008554

The monitoring of K+ in saliva, blood, urine, or sweat represents a future powerful alternative diagnostic tool to prevent various diseases. However, several K+ sensors are unable to meet the requirements for the development of point-of-care (POC) sensors. To tackle this grand-challenge, the fabrication of chemiresistors (CRs) based on 3D networks of Au nanoparticles covalently bridged by ad-hoc supramolecular receptors for K+, namely dithiomethylene dibenzo-18-crown-6 ether is reported here. A multi-technique characterization allows optimizing a new protocol for fabricating high-performing CRs for real-time monitoring of K+ in complex aqueous environments. The sensor shows exceptional figures of merit: i) linear sensitivity in the 10–3 to 10–6 m concentration range; ii) high selectivity to K+ in presence of interfering cations (Na+, Ca2+, and Mg2+); iii) high shelf-life stability (>45 days); iv) reversibility of K+ binding and
release; v) successful device integration into microfluidic systems for real-time monitoring; vi) fast response and recovery times (<18 s), and v) K+ detection in artificial saliva. All these characteristics make the supramolecular CRs a potential tool for future applications as POC devices, especially for health monitoring where the determination of K+ in saliva is pivotal for the early diagnosis of diseases.

  New insights in the slow ligand exchange reaction between Cr(III)-EDTA and Fe(III), and direct analysis of free and complexed EDTA in tannery wastewaters by liquid chromatography - Tandem mass spectrometry

Marco Roverso, Valerio Di Marco, Gabriella Favaro, Iole Maria Di Gangi, Denis Badocco, Mirco Zerlottin, Daniele Refosco, Andrea Tapparo, Sara Bogialli, Paolo Pastore.

Rivista: Chemosphere 2021 Volume 264 (1), 128487, IF 5.778

DOI: https://doi.org/10.1016/j.chemosphere.2020.128487

Abstract: EDTA and soluble Cr(III) are usually both present in wastewaters coming from treatment plants handling tannery effluents. A well-established method to determine EDTA is based on the conversion of free and complexed EDTA into its Fe(III) complex. This procedure gives inconsistent data when Cr(III)-EDTA is present. This fact was here demonstrated by studying the kinetics of the exchange reaction between Fe(III) and Cr(III)-EDTA at 90 °C and various pH values, from acidic to neutral. The reaction is very slow (several weeks); the slow kinetics of conversion of Cr(III)-EDTA to Fe(III)-EDTA is even more accentuated at room temperature and the low concentrations of reactants in wastewaters. The presence of EDTA complexes of Fe(III) and Cr(III) was demonstrated in industrial effluents and wastewaters by developing a selective method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS), which was able to detect free and complexed EDTA at concentration levels <1 μM. A systematic underestimation of the EDTA expressed as Fe(III) complex was demonstrated in samples containing Cr(III)-EDTA. Cr(III)-EDTA was identified for the first time as a component of wastewater samples at a concentration level of about 2 μM and turned out to be an inert species that significantly contributes to the final soluble Cr amount. This study gives new insights into the inertness of Cr(III) toward metal exchange equilibria of EDTA complexes, resolves a bias in the analysis of total EDTA in samples containing Cr(III)-EDTA, allowing the direct determination of free and complexed EDTA by LC-MS.

  Elucidation of the Intersystem Crossing Mechanism in a Helical BODIPY for Low-Dose Photodynamic Therapy

Zhijia Wang, Ling Huang, Yuxin Yan, Ahmed M. El-Zohry, Antonio Toffoletti, Jianzhang Zhao, Antonio Barbon, Bernhard Dick, Omar F. Mohammed, and Gang Han

Angew. Chem. Int. Ed. 2020, 59, 16114–16121

Impact Factor of 12.959 (2019)

https://doi.org/10.1002/anie.202005269

Intersystem crossing (ISC) of triplet photosensitizers is a vital process for fundamental photochemistry and photodynamic therapy (PDT). However, the currently effective long wavelength operating photosensitizers have to rely on heavy atoms to enhance ISC. Unfortunately, the heavy atoms, besides its toxicity, can also cause significant reduction in the triplet excited state lifetime of the photosensitizers, which are fundamentally detrimental to further applications. To overcome this challenge, we report on the discovery of the co-existence of superior intersystem crossing and the long triplet excited lifetime in a heavy atom-free Bodipy helicene molecule. Via comprehensive theoretical computation and advanced time-resolved electron paramagnetic resonance spectroscopy, this unique property is evidently confirmed to be directly associated with its unusual twisted molecular structure and reduced symmetry. We showed that such a twisted Bodipy helicene molecule shows exceptionally intense long wavelength absorption (abs coeff. = 1.76 ´ 105 M-1cm-1 at 630 nm), superior triplet quantum yield (yield = 52%) and a super long-lived triplet state (lifetime = 492 us), leading to unprecedented performance as a triplet photosensitizer for PDT. Moreover, nanoparticles constructed with such helical Bodipy triplet photosensitizer were found to achieve surprisingly efficient PDT mediated antitumor immunity amplification with ultra-low dose (0.25 ug/kg body weight), which is found to be about hundreds of time lower than the existing PDT reagents. Our study paves the way to design the next generation of triplet photosensitizers, which should be significant on both fronts: fundamental science and clinical applications.