The development of efficient and sustainable strategies for carbon capture and storage is essential to mitigate the escalating impacts of climate change. Mineral carbonation using calcium silicates offers a permanent and environmentally safe route for CO2 sequestration, but conventional approaches are limited by slow kinetics under ambient conditions and often rely on energy-intensive activation methods. Here, we report a novel solid-state approach to enhance the reactivity of natural wollastonite by employing Pulsed Laser Deposition (PLD) to fabricate thin films with tailored morphology. Unlike previous studies relying on synthetic targets, we directly used a natural wollastonite mineral for PLD. By varying the deposition atmosphere, we obtained compact films in vacuum and nanofoams in oxygen. While crystalline wollastonite is not preserved in the deposited films and amorphous calcium silicate phases are instead formed, both film morphologies exhibit significant CO2 uptake through carbonate formation. Comprehensive characterization was performed by a multitechnique approach, including variable-pressure scanning electron microscopy and scanning transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and contact angle measurements. The results revealed that nanofoam morphology promotes enhanced wettability, facilitates rapid CO2 uptake and retention, and ultimately leads to higher carbonation compared to compact films. This additive-free PLD approach provides a potentially scalable, low-energy platform for mineral-based CO2 capture, advancing the use of natural calcium silicates in carbon removal technologies.

The preservation of molecular reactivity on catalytic surfaces is one of the main key challenges in the fabrication of ordered organic-inorganic hybrid architectures. In this work, we investigate the behavior of a prototypical reactive molecule: a bromo-substituted naphthalimide derivative (Br-PNI) deposited in ultra-high vacuum on an iron passivated surface, either left as-prepared or pre-covered with an ordered zinc porphyrin monolayer. X-ray photoelectron spectroscopy reveals that the bare iron passivated surface promotes partial cleavage of the carbon-bromine bond even at room temperature, suggesting a catalytic activity toward dehalogenation reactions. This is also consistent with the flat-lying configuration of these molecules, as assessed by near-edge x-ray absorption fine structure (NEXAFS) analysis, which promotes direct contact with the substrate. In contrast, when Br-PNI is deposited on top of the zinc porphyrin monolayer, wetting the entire surface, axial coordination between the zinc ion and the Br-PNI pyridyl group induces an upright, out-of-plane molecular orientation, effectively separating the reactive bromine substituent from the catalytic surface. These results demonstrate that axial coordination with ordered porphyrin monolayers can simultaneously control molecular orientation and inhibit unwanted surface-catalyzed reactions, thereby providing a general strategy for integrating reactive functional groups into well-defined multilayer architectures.

Abstract Thin inorganic films, such as metal oxides, are frequently employed as functional materials for decoupling or optimization of the interaction between molecular magnetic layers and metallic surfaces. In the case of single-molecule magnet (SMM) deposits, an effective decoupling layer can reduce the hybridization with the metallic substrate, which would otherwise suppress their intrinsic magnetic bistability. In this work, we investigate the potential of an ultra-thin Fe oxide layer as a substrate for the Tb(III) bis-phthalocyaninato (TbPc 2 ) SMM in technological platforms. A multi-technique approach was employed to evaluate the integrity of a TbPc 2 sub-monolayer (ML) deposit and to determine the molecular adsorption geometry at the surface. Furthermore, large-scale facilities experiments were performed, and x-ray magnetic circular dichroism was used to probe the magnetic properties of the TbPc 2 sub-ML. The central finding is that while the magnetic moments and electronic configuration of the molecule are preserved, the characteristic slow magnetic relaxation is suppressed. This highlights the critical role of substrate phonon stiffness and tunnel barrier thickness in stabilizing the SMM behaviour.

Thin inorganic films, such as metal oxides, are frequently employed as functional materials for decoupling or optimization of the interaction between molecular magnetic layers and metallic surfaces. In the case of single-molecule magnet (SMM) deposits, an effective decoupling layer can reduce the hybridization with the metallic substrate, which would otherwise suppress their intrinsic magnetic bistability. In this work, we investigate the potential of an ultra-thin Fe oxide layer as a substrate for the Tb(III) bis-phthalocyaninato (TbPc2) SMM in technological platforms. A multi-technique approach was employed to evaluate the integrity of a TbPc2 sub-monolayer (ML) deposit and to determine the molecular adsorption geometry at the surface. Furthermore, large-scale facilities experiments were performed, and x-ray magnetic circular dichroism was used to probe the magnetic properties of the TbPc2 sub-ML. The central finding is that while the magnetic moments and electronic configuration of the molecule are preserved, the characteristic slow magnetic relaxation is suppressed. This highlights the critical role of substrate phonon stiffness and tunnel barrier thickness in stabilizing the SMM behaviour.

The two-birds-one-stone mineralization of CO2 by olivine, is a promising method to both capture carbon directly from the atmosphere and at the same time locking it for storage or utilization. Converting olivine to the nanoscale considerably enhances the kinetics without the need for high temperatures or pressures. Here we present the fabrication of olivine nanoparticles from a natural rock that were fabricated in a gas aggregation magnetron nanoparticle generator. The nanoparticle yield was optimized by enhancing the argon plasma sputter plasma by hydrogen introduction and varying the aggregation distance. The hysteresis of the argon sputter plasma with respect to power is a promising property towards energy efficiency. The formation of well-defined olivine nanoparticles and their subsequent absorption of atmospheric CO2 was confirmed by a suite of techniques. The olivine sputter target surface revealed an intricate interplay between the sputter plasma and olivine composition in terms of crystallinity and morphology. More broadly, this work forms the next step in the practical application of Olivine nanoparticles for economical carbon capture and storage, it also is the starting point for the use of this specific nanoparticle technology for mineral-to-nanoparticle conversion.

Abstract This study investigates the fundamental mechanisms governing the controlled orientation and stacking of heteroaromatic molecules at organic-inorganic interfaces under ultra-high vacuum conditions. We focus on the adsorption behavior of N,N’-di(4-pyridyl)−1,8:4,5-naphthalenetetracarboxydiimide (DPNDI) molecules on a Fe(001)-p(1×1)O surface, both with and without an intermediate layer of ZnII-tetraphenylporphyrin (ZnTPP). By strategically introducing the ZnTPP layer, we demonstrate the ability to tune the molecular arrangement of DPNDI, switching between a lying down orientation on the bare Fe(001)-p(1×1)O surface and a standing-up orientation when coordinated to zinc(II) ions. Using a combination of near edge x-ray absorption fine structure (NEXAFS) spectroscopy, low-energy electron diffraction (LEED), and scanning tunneling microscopy (STM), we explore the competing van-der-Waals and axial coordination interactions, elucidating how these forces dictate the molecular adsorption configuration. By integrating surface-sensitive experiments with density functional theory calculations, we provide a quantitative description of the adsorption energetics and elucidate the role of molecular coverage in determining adsorption geometry and molecular orientation. Our experimental results are reinforced by first principle calculations, which shed light on the energetic landscape underlying these arrangements. The theoretical insights reveal how molecule-substrate and intermolecular interactions promote or inhibit the formation of vertically stacked heterostructures. The comprehensive understanding regarding intermediate molecular layers as agent to control molecular orientation may pave the way to the precise design of functional heterostructures in applications such as organic electronics and molecular sensing.

Organic It-conjugated materials have revolutionized the landscape of optoelectronics and are now widely used in key technologies such as organic light-emitting diodes (OLEDs), organic photovoltaic cells (OPVs), organic fields transistors (OFETs) and sensors. Today, there is a growing interest in pushing the frontier of organic optoelectronics towards the near infrared (NIR) region, unlocking new applications. In this work, we introduce a novel NIR photoresponsive material active in the 700-1500 nm range, based on inorganic-organic heterojunction architecture. This system pairs molybdenum oxide (MoO3) with a newly developed large band-gap donor molecule featuring a benzodithiophene core and triarylamine unit. The ease of synthesis, good thermal stability and optimal film forming properties of the new donor material make this approach extremely appealing. We show the processing of the heterostructure by vacuum-evaporation, realizing an interfacial charge transfer complex with impressive NIR absorption properties, whose main features have been studied by photoemission and optical absorption techniques. We demonstrated that the hybrid material can be effectively employed in NIR photodetectors.

The controlled synthesis of biocompatible nanomaterials with tailored composition, size, and functionalities has driven the advancement of nanomedicine, enabling the development of innovative diagnostic and therapeutic strategies. A key challenge in this field is the design of nano-objects exhibiting multiple functionalities, each dedicated to a specific diagnostic or therapeutic purpose. Among these, synthetic stoichiometric chrysotile nanotubes stand out as a highly biocompatible class of non-carbon nanotubes, already demonstrating their potential for diverse applications, including fluorescence, magnetism, singlet-oxygen generation, and scintillation. Expanding this functional versatility, we report a finely tunable approach for controlling the surface silanization using 3-aminopropyl-trimethoxysilane. This is achieved via a microwave-assisted synthesis, which enables mild reaction conditions and significantly reduces processing time. A comprehensive multi-technique characterization is employed to elucidate the structural and chemical features of the mineral-silane interface and the underlying reaction mechanism.

The continuous research on electrocatalytic nanomaterials for critical raw materials replacement has returned the important class of Platinum-group-metal-free electrocatalysts (PGM-free), based on C, N, and non-noble transition metals. PGM-free are employed in Fuel Cells, Zinc-Air batteries, and Electrolyzers to catalyze important energy-related reactions. They are usually synthesized following a chemical route based on mixing, pyrolyzing, and postprocessing of specific N- and transition metal-containing compounds into conductive C structures, leading to a high content of byproducts. Herein, for the first time, a new approach for PGM-free synthesis is investigated, based on nitrogen implantation via ion beam produced with a Kaufman apparatus, and iron evaporation inside a clean chamber. The performed investigation, based on a model sp2 carbonaceous material (vertically aligned carbon nanotubes), showed similarities to the chemical route in terms of surface functionalization with the possibility to maximize the pyridinic N content, paving the way for the first time to the synthesis of nitrogen-compound-free nanoelectrocatalysts.

Interfaces between molecular layers and ferromagnetic materials, also called spinterfaces, are the test bed for the development of molecular spintronics, unveiling new effects and opportunities for novel potential applications. Among several combinations of materials that have shown intriguing behaviors, spinterfaces based on antiferromagnetic materials received much less consideration, despite the dramatic increase in attention recently drawn by the antiferromagnetic declination of spintronics. In this work, an antiferromagnetic spinterface based on the transition metal oxide NiO, a widely studied antiferromagnetic insulator with one of the highest critical temperatures, has been realized and characterized. As for the molecular counterpart, Co tetraphenyl porphyrin (CoTPP) is a very promising choice, being sublimable in vacuum and paramagnetic. CoTPP/NiO(001) spinterfaces are experimentally investigated with respect to their morphology, structure, electronic, and magnetic properties. Theoretical calculations have also been performed to circumstantiate and support the measurements. Although characterized by a relatively weak interface coupling, spin‐dependent hybridization is observed at the interface, which makes the CoTPP/NiO a perfect system for initiating the exploration of a molecular antiferromagnetic spintronics.

Pulsed laser-deposited amorphous carbon nanofoams are potential candidate for electrochemical energy storage applications due to ultra-light weight, large volumetric void fractions, and co-existence of sp, sp2 and sp3 carbon hybridization. It is known that charge storage in carbon nanostructures containing disordered sp2-domains is determined by their wettability, surface area, and porosity. However, their charge-storage performance is limited to the areal capacitance of the order of a few mF/cm2. We enhanced the supercapacitor performance of nitrogen-doped amorphous carbon nanofoam by engineering its wettability and sp2-C/sp3-C ratio by vacuum annealing. The specific capacitance was enhanced by about fifty times and the device voltage increased from 0.8 to 1.1 V compared to as-grown carbon nanofoam. In addition, we examined for the first time the initial increase in specific capacitance of the aqueous symmetric supercapacitor with respect to the scan rate, employing in-situ measurements coupling Raman spectroscopy and electrochemistry. We attribute this effect, observed but generally not explained in previous works in the literature, to the electrochemical activation induced by structural changes during the charge storage performance. This optimization of pulsed laser deposited carbon nanofoam may open an avenue for fabricating lightweight and porous nanostructures for advanced macro-to-micro-supercapacitor devices.

Coordination polymers may be synthesized by linear bridging ligands to metal ions with conventional chemistry methods (e.g. in solution). Such complexes can be hardly brought onto a substrate with the chemical, spatial and geometrical homogeneity required for device integration. Instead, we follow an in situ synthesis approach, where the anchoring points are provided by a monolayer of metal(ii)-tetraphenylporphyrin (M-TPP, M = Cu, Zn, Co) grown in vacuum on the rutile-TiO2(110) surface. We probed the metal affinity to axial coordination by further deposition of symmetric dipyridyl-naphthalenediimide (DPNDI). By NEXAFS linear polarization dichroism, we show that DPNDI stands up on Zn- and Co-TPP thanks to axial coordination, whereas it lies down on the substrate for Cu-TPP. Calculations for a model pyridine ligand predict strong binding to Zn and Co cations, whose interaction with the O anions underneath is disrupted by surface trans effect. The weaker interactions between pyridine and Cu-TPP are then overcome by the strong attraction between TiO2 and DPNDI. The binding sites exposed by the homeotropic alignment of the ditopic DPNDI ligand on Zn- and Co-TPP are the foundations to grow coordination polymers preserving the lateral coherence of the basal layer.

By employing an original experimental setup combining atomic force microscopy (AFM) and Raman spectroscopy to investigate opaque substrates in a liquid environment, the stability of fingerprints (latent or with synthetic residues) left for several hours in acidic water (mimicking acid rain) is studied. It is shown that, despite the general detriment of the fingerprint after a few hours, persistent residuals are found, showing good morphological stability and a characteristic Raman spectrum, which can be considered reliable proof of the presence of a fingerprint on the investigated surface. These findings demonstrate the importance of combining microscopic and spectroscopic analyses in scientific forensic investigations.

Abstract Vanadyl(IV) 5,10,15,20‐tetraphenylporphyrin (VOTPP) is an S = 1/2 molecular system with remarkable spin qubit properties. Its structure offers a higher chemical tunability with respect to archetypal molecular qubits, such as vanadyl(IV)Phthalocyanines (VOPc), and a less rigid organic scaffold where peripheral phenyl rings can promote electron decoupling from the substrate. The properties of a VOTPP monolayer on the Ag(100) surface by photoemission spectroscopies and synchrotron radiation are studied. The results indicate that the electronic and spin features of the massive phase are retained in the monolayer. Moreover, X‐ray photoelectron spectroscopy revealed the existence of two distinct species characterized by varying strengths of molecule‐surface interactions. Like VOPc, these species can be assigned to molecules with the vanadyl group oriented upward or toward the surface. However, in contrast to VOPc, only subtle screening effects are observed in the oxygen‐down configuration, suggesting a more pronounced decoupling effect inherent in the VOTPP structure. This opens broader perspectives for investigations focusing on spin characteristics at the single‐molecule level.

To mitigate climate change, CO2 sequestration from the atmosphere is being considered as a method to reduce its greenhouse effect and subsequently lower the Earth's surface temperature. A promising approach is the storage of CO2 in minerals, of which Olivine is a promising candidate due to its Earth abundance and high CO2 absorption capacity, which is of the order of 50 wt.%. A bottleneck for Olivine carbonation is the slow reaction rate at ambient conditions, which previously resulted in supplying CO2 at extreme pressures and temperatures to force carbonation. In this study, nanoscale Olivine particles are fabricated, which due to their high surface‐to‐volume ratio, reach a very high carbonation conversion at a time scale of minutes at ambient conditions. The carbonation is measured by X‐ray photoelectron spectroscopy (XPS), which yielded both the presence of carbonates as well as information on the Olivine oxidation state, in agreement with electron diffraction analysis. This work forms the basis for employing Olivine nanoparticles, as fabricated by the relatively simple method of magnetron sputtering, to capture CO2 from the atmosphere at economic conditions.

We present a system for the growth of molecular films in vacuum that exhibits high versatility with respect to the choice of molecular species. These can be either evaporated from powders or injected from solutions using an electrospray system, making it possible to handle particularly large and/or fragile molecules in a controlled environment. The apparatus is equipped with a reflectance anisotropy spectroscopy system for the in situ characterization of the optical response of the films and can be directly connected to a photoelectron spectrometer without breaking the vacuum. The system is conceived for the study and characterization of porphyrin films. Here, to showcase the range of possible analyses allowed by the experimental setup and test the operation of the system, novel results are provided on electrospray deposition on highly oriented pyrolytic graphite of Zn tetraphenyl porphyrins and Zn proto porphyrins, the latter featuring fragile side groups that make deposition from solution more attractive. In situ characterization is complemented by ex situ atomic force microscopy. Thanks to this multi-technique approach, changes in the film morphology and spectroscopic response are detected and directly related to the choice of the molecular moiety and growth method.

Silicate nanoparticles, otherwise referred to as very small grains (VSGs) [1], occur in various astrophysical environments. These grains experience substantial processing (e.g., amorphization) during their lifetime in the diffuse interstellar medium due to events such as grain-grain collisions and irradiation [2]. Moreover, several studies have pointed out that the main building blocks of these silicates are O, Si, Fe, Mg, Al and Ca, all elements that are among the principal constituents of the Earth’s surface [3], thus leading to the name “astronomical silicates”. However, the structure and chemical evolution together with the origin of these grains are still poorly understood and intensively debated [4,5]. The aim of this study is the simulation of space weathering processes on olivine single crystals by liquid phase pulsed laser ablation (LP-PLA). The study of the resulting structure of both the target and the ablated material together with their chemical evolution has been carried out by a multiple technique characterization. In particular, spectroscopy and dynamic light scattering measurements, analyses of the electrostatic properties and reactivity to acids and bases on the obtained colloidal solutions of the ablated nanoproducts have been performed and coupled with high-resolution transmission electron microscopy (HR-TEM). Selected olivine target crystals (Fo87) from the São Miguel island (Azores) were analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDX). LP-PLA experiments were performed with a Nd:YAG laser focused via a singlet lens onto the surface of the target, which was fixed at the bottom of a polystyrene box filled with 4 ml of deionized water (type 1) to immerge it completely. Laser pulses of 5 ns and 100 mJ simulate the timeframe and energy exchange occurring during grain-grain interstellar collisions [6] and they generate a plasma plume at the crystal/liquid interface. The rapid cooling induced by the confining liquid layer brings about the condensation of the chemical vapor it contains with production of a colloidal solution of nanoparticles. These solutions were analyzed by dynamic light scattering techniques and optical absorption spectroscopy in the range from 200 nm to 1100 nm (6.20 eV - 1.13 eV). Absorption measurements on the colloidal solutions have been compared against reference colloidal solutions dispersed in deionized water (i.e. mesoporous silica [SiO2] nanoparticles, brucite [Mg(OH)2] nanoparticles, aluminum hydroxide [Al(OH)3] nanoparticles, chrysotile [Mg3Si2O5(OH)4] nanotubes, and synthetic forsterite [Mg2SiO4] nanoparticles). Moreover, additional absorption analyses have been carried out as a function of the addition of known aliquots of sulfuric acid and sodium hydroxide solutions. TEM/EDS analyses were then performed on the ablated nanoparticles deposited via electrophoresis on C-coated Cu grids and compositional variations of the ablated target were determined by X-ray photo-emission spectroscopy analyses. The size distribution of LP-PLA synthesized nanoparticles is typically multimodal due to aggregation phenomena. Aggregation is consistent with the measured ζ-potential, which is negative with a relatively low absolute value, within the range 30-50 mV. Nonetheless, a recurrent mode is centered at about 2 nm (hydrodynamic diameter) and it is consistent with the measured size distribution obtained by transmission electron microscopy analysis (average nanoparticles diameter around 3-5 nm). Optical absorption measurements on the ejected material show a main band around 215 nm. This feature is very similar to the “B2 band” reported in several studies on silica glass [7] and ascribed to oxygen vacancies, but its nature is still far to be fully understood. We also found that this feature at 215 nm is very common among both Si and Mg compounds (e.g., Si-oxide, Mg-hydroxide, chrysotile). Moreover, additional absorption bands in the range 240-350nm are observed suggesting the formation of new space weathering products as result of the ablation process. Therefore, these results suggest that substantial chemical processing might be expected during space weathering of “typical” interstellar grains into VSGs. Moreover, coupling these experimental results with remote sensing datasets will provide fundamental information about the origin and evolution of these silicate grains. Acknowledgments: M.M is supported by the SIMP PhD thesis award. References: [1] Witt A. N. (2000) Journal of Geophysical Research: Space Physics, 105(A5), 10299-10302. [2] Carrez P. et al. (2002) Meteoritics & Planetary Science, 37, 1599-1614. [3] Henning T. (2010) Annual Review of Astronomy and Astrophysics, 48, 21-46. [4] Draine B. T. (2003) Annual Review of Astronomy and Astrophysics, 41, 241-289. [5] Escatllar A. M. et al. (2019) ACS Earth and Space Chemistry, 3, 2390-2403. [6] Loeffler M. J. et al. (2016) Meteoritics & Planetary Science, 51, 261-275. [7] Skuja L. N. et al. (1984), Solid State Communications, 50, 1069-1072.

AbstractAt organic molecule/metal interfaces for electronic applications, it is required of the metal surface to be passivated in view of preserving the molecular properties of the ordered organic layer. This can be achieved by screening the metal with a single atomic layer of O, namely, ultra‐thin metal oxide (UTMO) layers. Cobalt tetraphenylporphyrins (CoTPP) on oxygen passivated Fe(001), with 1 ML O coverage, have revealed a molecule/substrate decoupling effect due to the formation of an ultra‐thin Fe oxide layer at the interface. However, the threshold concentration of surface O required to observe the decoupling effect has not been assessed yet. In this work, the possibility of stabilizing different ultra‐thin Pd oxide superstructures, characterized by a different number of O atoms per unit cell, is exploited to investigate the O decoupling effect on CoTPP films. Two Pd oxide superstructures are considered: Pd(001)‐p(2 × 2)O and Pd(001)‐p(√5 × √5)R27°O, with 0.25 and 0.80 ML O coverages, respectively, which are characterized by low‐energy electron diffraction (LEED), X‐ray and ultra‐violet photoelectron spectroscopies (XPS/UPS) and inverse photoemission spectroscopy (IPES). The results suggest a lower limit of 0.80 ML O coverage as a passivation interlayer to obtain an ordered and decoupled CoTPP monolayer on Pd(001).

Heat is an inexhaustible source of energy, and it can be exploited by thermoelectronics to produce electrical power or electrical responses. The search for a low-cost thermoelectric material that could achieve high efficiencies and can also be straightforwardly scalable has turned significant attention to the halide perovskite family. Here, we report the thermal voltage response of bismuth-based perovskite derivates and suggest a path to increase the electrical conductivity by applying chalcogenide doping. The films were produced by drop-casting or spin coating, and sulfur was introduced in the precursor solution using bismuth triethylxanthate. The physical-chemical analysis confirms the substitution. The sulfur introduction caused resistivity reduction by 2 orders of magnitude, and the thermal voltage exceeded 40 mV K-1 near 300 K in doped and undoped bismuth-based perovskite derivates. X-ray diffraction, Raman spectroscopy, and grazing-incidence wide-angle X-ray scattering were employed to confirm the structure. X-ray photoelectron spectroscopy, elemental analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were employed to study the composition and morphology of the produced thin films. UV-visible absorbance, photoluminescence, inverse photoemission, and ultraviolet photoelectron spectroscopies have been used to investigate the energy band gap.