Sub-stoichiometric molybdenum oxide (MoOx) has attracted significant attention as hole-transport/selective layer in optoelectronic devices. However, its integration on Si is hindered by interfacial redox-reactions that can alter oxide stoichiometry and electronic properties.In this work, MoOx films, 5 nm thick, were deposited by non-reactive RF sputtering from a stoichiometric MoO3 ceramic target onto bare and thermally-oxidized Si substrates. Morphological analyses confirmed the formation of continuous and dense coatings, Kelvin probe mapping revealed spatially uniform WF of 5.06 eV. Angle-resolved XPS showed sub-stoichiometric composition (x=2.6) regardless of substrate, with no variations across the film thickness. These results were corroborated by HAADF-STEM, which revealed uniform Mo and O distributions, confirming the absence of interfacial oxide reactions. Compared to thermally evaporated counterparts, sputtered films exhibit superior compositional stability due to the higher kinetic energy of sputtered species involved in the film growth. Overall, non-reactive sputtering enables the growth of stable films suitable for optoelectronic and photovoltaic applications.

Abstract The increasing demand for sustainable technologies and resource efficiency is driving the development of materials that can both mitigate CO2 emissions and recover valuable metals from e-waste. In this work, we report a simple and environmentally friendly approach for fabricating catalytic surfaces based on laser-reduced graphene oxide (rGO) decorated with gold or copper nanoparticles (Au or Cu NPs). The process involves laser reduction of graphene oxide, followed by immersion in aqueous Au3+ or Cu2+ model solutions, simulating metal leachate from an e-waste recovery process. Morphological and chemical analyses (SEM and XPS) confirm the formation of metallic nanoparticles. The resulting metal@rGO surfaces were tested for CO2 photothermo-catalytic conversion under simulated solar irradiation, achieving conversion efficiencies above 40%, with CO and CH4 as the main products. Both catalytic surfaces displayed comparable activity and good stability over three consecutive cycles. This method integrates CO2 conversion with metal recycling, offering a promising route toward circular catalytic materials.

Stoichiometry of molybdenum oxide, MoOx, thin films was controlled by simply modulating the argon working pressure during the non-reactive sputtering deposition. Rutherford Backscattering Spectrometry revealed that the O/Mo ratio increased between 2.6 and 3.0 as the argon pressure increased. X-Ray Photoemission Spectroscopy (XPS) analyses pointed out that the sub-stoichiometry led to the formation of oxygen vacancies, closely related to the presence of Mo5+ reduced oxidation state, while in fully stoichiometric films only Mo6+ oxidation state appeared. The strong correlation between composition and optical properties was demonstrated through optical absorption measurements. Sub-stoichiometric films exhibited a narrower bandgap and significant infrared absorption at 1.55 eV, attributed to increased disorder and a higher number of defects, such as oxygen vacancies. Finally, by merging the XPS and optical absorption data, we demonstrated that the band structure of MoOx was effectively controlled by simply modulating the Argon deposition pressure. This tunability offers significant potential for tailoring the optical and electronic properties of MoOx for applications in energy storage, photovoltaic and photonic devices.

The need of achieving low-impact and low-cost functional materials through sustainable and efficient methodologies is one of the goals of the current research in the field of materials science and energy storage. In this study, a new facile route for obtaining battery-like electrode Bi-based films is presented. Specifically, 1.3 mu mthick (3-Bi2O3 films were prepared from oxynitrate via a simple sol-gel/elution process upon titanium foils, followed by annealing in forming gas at 350 degrees C. A multi-technique approach, involving Raman, X-ray Photoelectron Spectroscopy, X-ray Diffraction, Scanning Electron Microscopy and optical characterization, demonstrates the formation of a nanocrystalline porous bismuth oxide (20-30 nm in size) consisting of (3-Bi2O3 phase with the crucial presence of Bi0. Annealing at 350 degrees C in different environments (i.e. air and N2), do not produce crystalline phases. The reported method improves the synthesis of (3-Bi2O3 phase through a 1.3 mu m-thick film realization and a controlled phase production by reactive annealing at moderate temperatures. Cyclic Voltammetry and Galvanostatic Charge Discharge analyses reveal a double-redox behaviour for the (3-Bi2O3 /Bi0 battery electrode with a specific capacity (capacitance) of 195 mA*h/g (350 F/g) at 0.5 A/g. The data highlight the promising usage of sol-gel/elution for the realization of 1.3 mu m-thick film for energy storage applications.

The need of achieving low-impact and low-cost functional materials through sustainable and efficient methodologies is one of the goals of the current research in the field of materials science and energy storage. In this study, a new facile route for obtaining battery-like electrode Bi-based films is presented. Specifically, ∼1.3 μm-thick β-Bi2O3 films were prepared from oxynitrate via a simple sol-gel/elution process upon titanium foils, followed by annealing in forming gas at 350°C. A multi-technique approach, involving Raman, X-ray Photoelectron Spectroscopy, X-ray Diffraction, Scanning Electron Microscopy and optical characterization, demonstrates the formation of a nanocrystalline porous bismuth oxide (20–30 nm in size) consisting of β-Bi2O3 phase with the crucial presence of Bi0. Annealing at 350°C in different environments (i.e. air and N2), do not produce crystalline phases. The reported method improves the synthesis of β-Bi2O3 phase through a ∼1.3 μm-thick film realization and a controlled phase production by reactive annealing at moderate temperatures. Cyclic Voltammetry and Galvanostatic Charge Discharge analyses reveal a double-redox behaviour for the β-Bi2O3 /Bi0 battery electrode with a specific capacity (capacitance) of 195 mA*h/g (350 F/g) at 0.5 A/g. The data highlight the promising usage of sol-gel/elution for the realization of ∼1.3 μm-thick film for energy storage applications.

Hydrogen evolution reaction (HER) plays a pivotal role in sustainable energy solutions, enabling efficient hydrogen production as a clean fuel alternative. However, developing cost-effective and high-performance electrocatalysts for HER remains a significant challenge. This study explores the fabrication of a nano-structured NiMo alloy by a cost-effective and scalable ball milling process, obtaining a high-performance electrocatalyst for HER in alkaline conditions. Two methods, separate or simultaneous ball milling of Ni powder and Mo/MoOx-based waste powder, are compared to evaluate their influence on the material physicochemical properties and catalytic activity. The NiMo nanostructures obtained by milling together the two powders exhibit remarkable improvements compared to the electrocatalyst prepared by mixing the separately milled powders, including a low overpotential of just 100 mV at a current density of 10 mA cm-2 and enhanced electron transfer efficiency. Comprehensive morphological, chemical, and electrochemical analyses revealed the critical role of synergistic metal interactions and process optimization. This study demonstrates the significant potential of a precisely engineered ball milling approach for developing efficient and sustainable electrocatalysts for water splitting applications.

In response to the growing demand for eco-friendly materials, derived from natural compounds for environmental applications, we developed an innovative catalyst based on kojic acid, a bio-derived metabolite produced by Aspergillus species. This work involved functionalizing the hydroxypyrone scaffold with an acrylic group, yielding a porous organic polymer (C-HPO) to remove hazardous metal. The resulting C-HPO exhibited exceptional chelating capacity for heavy metal ions, including mercury (Hg), copper (Cu), and iron (Fe), highlighting its potential for environmental remediation and resource recovery. Furthermore, by complexing C-HPO with iron ions, we created a photo-Fenton-like system (C-HPO/Fe), enabling its use in advanced oxidation processes. UV-Vis absorption analyses revealed that the C-HPO/ Fe system efficiently degrades various emerging contaminants, including lomefloxacin (LOM), doxycycline (DOX), desethyl atrazine (DEA), and methylene blue (MB). Remarkably, as little as 1 g/L of the C-HPO/Fe catalyst achieved complete degradation of these pollutants, highlighting its high catalytic efficiency and promise for sustainable contaminant treatment.

Silver-terephthalate MOFs with various morphologies were obtained via interfacial synthesis. Remarkable antibacterial activities were observed, exhibiting enhanced efficacy and exceptional stability up to three months.

Lithium niobate is a lead-free material which has attracted considerable attention due to its excellent optical, piezoelectric, and ferroelectric properties. This research is devoted to the synthesis through an innovative sol–gel/spin-coating approach of polycrystalline LiNbO3 films on Si substrates. A novel single-source hetero-bimetallic precursor containing lithium and niobium was synthesized and applied to the sol–gel synthesis. The structural, compositional, and thermal characteristics of the precursor have been tested through attenuated total reflection, X-ray photoelectron spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The LiNbO3 films have been characterized from a structural point of view with combined X-ray diffraction and Raman spectroscopy. Field-emission scanning electron microscopy, energy dispersive X-ray analysis, and X-ray photoelectron spectroscopy have been used to study the morphological and compositional properties of the deposited films.

We report on copper nanoparticles produced by laser ablation, in acetone and methanol, from a Cu target using a 1064 nm nanosecond pulsed laser. The morphology, size, structure and chemical composition of the nanoparticles are investigated as a function of the solvent employed. Different analyses confirm the metallic nature of the nanoparticles, without amorphous carbon or copper oxides shells. Then, the nanoparticles are embedded between two transparent electrodes, aluminium-doped zinc oxide (AZO) and zirconium-doped indium oxide (IZrO) as top and bottom layers, respectively. The Glass/IZrObott/Cu nanoparticles/AZO(top) structures are synthesized and optimized as plasmonic and conductive structure for photovoltaic applications. Optical properties show a strong dependence on the thermal annealing at 200 degrees C and type of copper nanoparticles embedded in transparent electrodes. The transparent electrode with the lowest E-gap limits the E-gap to the whole structure. The best structure shows a mean value of transmittance in the visible-NIR range of -79% with an E-gap of 3.43 eV and, moreover, it shows diffused transmittance between 2.5 and 6% in VIS-NIR range and a sheet resistance of 79 Omega/sq. The performances of the best structure are tested measuring the internal quantum efficiency of a tandem solar cell, getting values as high as 89%.

Abstract Alzheimer's disease (AD) is a diffused neurodegenerative disorder affecting people in advanced age causing loss of memory and dementia. Nowadays, diagnosis and treatment of AD are still challenging due to the lack of diagnostic systems that allow for an early and reliable diagnosis and therapy monitoring. Moreover, conventional strategies for AD diagnosis are based on brain imaging techniques that are invasive and expensive for early and massive screening. Phage display approach, using engineered phage probe for direct amyloid‐β (Aβ)‐autoantibodies detection, overcome these limitations leading to the possibility of safe and low‐cost screening. Moreover, the combination with silicon technology further improves the easiness of diagnosis due to the portability of devices and the integration of sensitive transduction signals. In this work, an innovative silicon‐based sensing technology is reported detecting Aβ‐autoantibodies, specifically Immunoglobulin G (IgG), in human sera by engineered M13‐phage probes (ADPP). The strategy hinges on a bio‐surface that is integrated on top of a silicon biosensor. Thanks to phages probes exposing Aβ‐mimic peptides, this chip can capture and reveal Aβ‐autoantibodies, discriminating between healthy and AD conditions. The surface chemistry is morphologically and chemically characterized and the phage‐based biosensor ability to recognise Aβ‐autoantibodies is proved by transduction with enzyme‐linked anti‐M13 antibodies.

The progressive increase in nitrate’s (NO3−) presence in surface and groundwater enhances environmental and human health risks. The aim of this work is the fabrication and characterization of sensitive, real-time, low-cost, and portable amperometric sensors for low NO3− concentration detection in water. Copper (Cu) micro-flowers were electrodeposited on top of carbon screen-printed electrodes (SPCEs) via cyclic voltammetry (with voltage ranging from −1.0 V to 0.0 V at a scan rate of 0.1 V s−1). The obtained sensors exhibited a high catalytic activity toward the electro-reduction in NO3−, with a sensitivity of 44.71 μA/mM. They had a limit of detection of 0.87 µM and a good dynamic linear concentration range from 0.05 to 3 mM. The results were compared to spectrophotometric analysis. In addition, the devices exhibited good stability and a maximum standard deviation (RSD) of 5% after ten measurements; reproducibility, with a maximum RSD of 4%; and repeatability after 10 measurements with the RSD at only 5.63%.

Controlling surface wettability is a major technological challenge. In this work, we employ the laser scribing method to control the wettability of laser-reduced graphene oxide by using different liquid media. The measured contact angle can be tuned from 50 degrees to 120 degrees, driven by the thermal conductivity and the boiling point of the solvent. While the contact angle is slightly related to the oxygen content, we show that higher contact angle is related to a higher surface roughness of the surface. This is a fast and inexpensive method to produce surfaces with controlled wettability.

Copper is efficient, has a high conductivity (5.8 × 107 S/m), and is cost-effective. The use of copper-based catalysts is promising for the electrocatalytic reduction of nitrates. This work aims to grow and characterize copper micro-crystals on Screen-Printed Electrodes (SPEs) for NO3− reduction in water. Copper micro-crystals were grown by cyclic voltammetry. Different cycles (2, 5, 7, 10, 12, 15) of copper electrodeposition were investigated (potential ranges from −1.0 V to 0.0 V, scan rate of 0.1 V s−1). Electrodeposition generated different morphologies of copper crystals on the electrodes, as a function of the number of cycles, with various performances. The presence of numerous edges and defects in the copper micro-crystal structures creates highly reactive active sites, thus favoring nitrate reduction. The manufactured material can be successfully employed for environmental applications.

An innovative biosensing strategy for the diagnosis of Alzheimer’s disease (AD) in human sera has been developed. The technology relied on a silicon flat substrate that was functionalized to perform a phage display detection of anti-amyloid beta (Aβ) antibodies, as AD markers, among the pool of IgGs of human sera. The substrate was derivatized with an interface able to bind and orient the IgGs for the detection operated by an engineered selective probe phage. The interface chemistry and its discrimination activity of healthy and AD sera have been fully characterized.

Monitoring of ammonium ion levels in water is essential due to its significant impact on environmental and human health. This work aims to fabricate and characterize sensitive, real-time, low-cost, and portable amperometric sensors for low NH4+ concentrations in water. Two strategies were conducted by cyclic voltammetry (CV): electrodeposition of Au nanoparticles on a commercial polyaniline/C electrode (Au/PANI/C), and CV of electropolymerized polyaniline on a commercial carbon electrode (Au/PANIep/C). Au NPs increase the electrical conductivity of PANI and its ability to transfer charges during electrochemical reactions. The electrode performances were tested in a concentration range from 0.35 µM to 7 µM in NH4+ solution. The results show that the Au/PANI/C electrode performs well for high NH4+ concentrations (0.34 µM LoD) and worsens for low NH4+ concentrations (0.01 µM LoD). A reverse performance occurs for the electrode Au/PANIep/C, with a 0.03 µM LoD at low NH4+ concentration and 0.07 µM LoD at high NH4+ concentration. The electrodes exhibit a good reproducibility, with a maximum RSD of 3.68% for Au/PANI/C and 5.94% for Au/PANIep/C. In addition, the results of the repeatability tests show that the electrochemical reaction of sensing is fully reversible, leaving the electrode ready for a new detection event.

Biobased catalysts play a crucial role in sustainable chemistry, using natural resources to support eco-friendly processes. While palladium catalysts are essential for various industrial applications, they often pose environmental challenges due to their non-reusability and tendency to degrade. To address these issues, we developed an innovative phenylalanine-based catalyst containing palladium (C-PhebPd) designed for the Suzuki-Miyaura reaction. The natural amino acids, used as monomers, chelate palladium, preventing leaching, unlike other heterogeneous catalysts that use palladium nanoparticles, which can be released over time, leading to catalyst degradation. Such catalyst exhibits outstanding performance in aqueous media at moderate temperatures, facilitating cross-coupling reactions between various aryl halides and arylboronic acids with high yields of up to 99%. The affordable synthetic procedure and C-PhebPd's stability make it potentially scalable for industrial applications. The robustness of this catalyst was also proved by recyclability tests up to seven cycles. Further investigation into its capabilities could unlock additional insights for various catalytic transformations. A phenylalanine-based palladium catalyst was developed for the Suzuki-Miyaura reaction, preventing palladium leaching. It demonstrated high yield (up to 99%) in aqueous media and can be reused up to seven times, making it scalable for industrial use.

Gold electroless deposition on nickel foam offers several advantages over traditional electrodeposition techniques. One of the main advantages is that it can produce uniform thickness coatings on complex shapes and geometries, such as porous and three-dimensional substrates like nickel foam. The resulting gold-nickel foam composite has high surface area and good electrical conductivity, making it suitable for various electrochemical applications, including catalysis, sensing, and energy storage. In this work we focused on the development of synthetic strategies to grow and optimize the surface coverage of gold on nickel foam and the evaluation of its suitability for the electrochemical reduction of nitrogen for ammonia synthesis. The gold electroless deposition on Ni Foam has been obtained by immersion in aqueous solution containing KAuCl4 and HCl, with or without stirring and addition of a surfactant agent (Isopropyl Alcohol). Depositions were performed by varying the immersion time from 30 seconds to 30 minutes. Scanning electron microscopy (SEM) has been employed to compare different deposition conditions and to optimize the morphology of the nanofilms, allowing higher catalytic activity. The electrochemical performance of the gold deposited on nickel foam was evaluated in a standard two compartments electrochemical cell using a Pt wire as counter electrode (CE), a saturated calomel electrode (SCE, saturated KCl) as reference and 0.1 M Na2SO4 solution as electrolyte. Electrochemical active surface area (EASA) and linear sweep voltammetry (LSV) have been adopted to evaluate the active area and the overpotential toward hydrogen evolution reaction (HER). Chronoamperometry experiments were carried out at various potentials to evaluate the performance of the catalyst for the electroreduction of nitrogen and ammonia synthesis. The amount of ammonia produced was measured by the indophenol blue method. The maximum NH3 yield of 2.8x10-11 mol s-1 cm-2 was achieved at -0.045 V vs RHE. The maximum faradaic efficiency of 5.8% was achieved at more positive potential (0.015 V vs RHE) due to the HER. The results show that the gold on nickel foam exhibits excellent electrochemical stability and high conductivity. This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under grant agreement No 101006941. This project started on the 1st of November 2020 with a duration of 42 months.

Finding proper strategies to control plasma polymerization processes is a crucial aspect to produce thin films with tailored characteristics. In this work, the validity of the Yasuda parameter W/FM (W: discharge power and FM: precursor feed rate) as a controlling parameter for a polymerization process assisted by an atmospheric pressure single electrode plasma jet and the aerosolized fluorinated silane precursor trimethoxy(3,3,3-trifluoropropyl)silane is demonstrated. The properties of thin films deposited under different W/FM values are discussed using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), water contact angle (WCA) measurements, and scanning electron microscopy (SEM). Results suggest the presence of two deposition domains as a function of W/FM (an energy-deficient domain and a monomer-deficient domain), each inducing coatings with different chemical and physical properties. Furthermore, coatings deposited under the same W/FM values exhibit similar characteristics regardless of the power and feed rate values adopted. Considering the potential use of the deposited coatings to increase the antiadhesive properties of implantable medical devices, preliminary results on coatings' antiadhesive activity against Pseudomonas aeruginosa and Staphylococcus aureus are presented.

In the field of sustainability, hydrogen (H2) is considered a clean fuel and a renewable energy source with no pollutant emissions. The production of H2 by water electrolysis is well-known among the scientific community. Still, alkaline electrolysis represents a challenging process and requires expensive materials have to be avoided in order to lower the impact of H2 production. This work deals with the production of copper (Cu) and nickel (Ni) nanoparticles (NPs) as catalysts for alkaline water splitting reactions. These NPs are synthesized using the pulsed laser ablation in liquid involving the ablation of Cu and Ni targets in methanol and ethanol. The morphological, structural, and compositional properties of the obtained NPs are studied. Then, a low amount of NPs-based catalyst (∼1μg/cm2) was loaded onto a nickel foam substrate and tested for both alkaline Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER). The best performance at 10 mA cm−2, in terms of overpotential (η), for OER was shown by Ni NPs, η = 327 mV, while for the HER, Cu NPs reached η = 211 mV at 10 mA cm−2 in aqueous 1M KOH. The ultra-low amount of the catalyst material makes these electrodes challenging in terms of mass activity [up to 14 A/mg at 10 mA cm−2] compared to the state of the art. In addition, the correlation between overpotential and the availability of electrons at the surface of the catalyst for H2 production was studied by using Mott–Schottky analysis.