Geopolymer foams are lightweight, porous materials increasingly recognized for their potential in sustainable construction, owing to their low density, tunable porosity, fire resistance, and environmentally friendly synthesis. Despite these advantages, their inherent thermal storage capability is relatively limited, which restricts their performance in applications where energy efficiency and thermal regulation are critical. To overcome this drawback, the present study focuses on the development of geopolymer foams enhanced with paraffin-based phase change materials (PCMs) encapsulated within diatomite. Diatomite, a naturally occurring siliceous material with a high surface area and porous structure, serves as an effective carrier for paraffin, ensuring good retention and reducing the risk of leakage during repeated melting and solidification cycles. The modified foams were prepared through the incorporation of diatomite-encapsulated PCM into the geopolymer matrix during the foaming process. Comprehensive characterization was carried out to evaluate the structural, thermal, and mechanical properties of the resulting composites. Scanning electron microscopy confirmed the successful distribution of PCM-loaded diatomite within the pore structure. At the same time, specific heat measurements highlighted a marked improvement in latent heat storage capacity without significant loss of insulating properties. Moreover, mechanical tests indicated that the addition of encapsulated PCM did not compromise the structural stability of the foams, maintaining adequate compressive strength for potential building applications. The results of this study demonstrate that integrating diatomite-encapsulated paraffin PCM into geopolymer foams provides a multifunctional material that combines thermal insulation with enhanced energy storage capacity. Such composites are particularly promising for applications in energy-efficient buildings, where passive thermal regulation and reduced energy consumption are increasingly important. Overall, the findings underscore the potential of geopolymer foams as sustainable construction materials with improved thermal management capabilities, contributing to the broader goals of energy conservation and environmental protection.

The accumulation of plastic waste is a considerable environmental concern, with continually low global recycling rates and an increasing reliance on landfilling. Incorporating waste plastics into asphalt pavements is a sustainable solution to divert waste from landfills and enhance pavement performance. This study integrates information from prior experimental and field investigations to assess the technical and environmental feasibility of plastic-modified asphalt. Peer-reviewed studies were examined, emphasizing polymer type, inclusion method (dry or wet process), particle size, and dosage, with performance metrics including rutting resistance, fatigue life, moisture susceptibility, and environmental effects. Comparative data were structured into tables and figures to discern performance trends and emphasize knowledge gaps. The results demonstrate that the use of 4–10% waste plastics can enhance rutting resistance by up to 40% and increase fatigue life by over 25%, depending on polymer type and modification method employed. Enhancements in stiffness and moisture resistance have been noticed; however, increased doses may diminish resistance to low-temperature cracking. Life cycle assessments indicate possible decreases in greenhouse gas emissions and significant diversion of plastics from landfills. The incorporation of waste plastics into asphalt can improve pavement durability and support circular economy goals, depending on the optimization of material selection and mix design parameters. The proposed conference presentation will feature comparative tables and charts from previous studies to graphically illustrate these findings and substantiate evidence-based discussions on sustainable pavement technologies.

Introduction: In high-temperature environments, heat exchangers require lightweight designs, high thermal resistance, and high effectiveness. Graphene-reinforced ceramic matrix composites (G-CMC) offer promising thermal properties for such applications. This study investigates the effectiveness changes of a block-type heat exchanger made of G-CMC, depending on the length and design, leveraging the potential of 3D printing in the production of complex geometries.

Methods: SolidWorks was used to create the solid model and perform the numerical analyses. First, flow analyses were performed on 180 mm long heat exchangers made of steel and G-CMC. Then, to examine the effect of channel geometry, each 4×4 mm channel was divided into four 1×4 mm parallel channels, keeping the total flow volume constant. This increased the contact surface area by approximately 2.5 times. Additionally, heat exchanger models with lengths of 180, 250, 450, and 600 mm were analyzed to examine the effect of heat exchanger length on effectiveness.

Findings: Using ceramic composite instead of steel resulted in an approximately 11% increase in effectiveness for the 180 mm design length heat exchanger. Subdividing the channels resulted in an 82% increase in effectiveness for the steel model and a 38% increase for the G-CMC model. Extending the heat exchanger length to 600 mm increased effectiveness by 56% for the steel model and 34% for the composite model. Furthermore, using G-CMC reduced heat exchanger mass by approximately 50%, and the potential to produce complex geometries with 3D printing could provides material and energy savings during the production process.

Conclusion: These findings demonstrate that material selection and geometric optimization are critical to achieving high effectiveness and sustainability in high-temperature heat exchanger applications. The results highlight the potential of G-CMC and additive manufacturing to produce lightweight and efficient heat exchangers for challenging thermal environments.

Lignin nanoparticles (LNPs) are sustainable nanomaterials obtained from agro-industrial residues, with increasing interest for different applications. Their biocompatibility and functional properties have made LNPs one of the most explored materials in food packaging, drug delivery, and photonic applications. The challenge with LNPs is the lack of uniformity in their production, as broad particle size distributions can limit their effectiveness in advanced applications that require size precision and homogeneity. This study presents the extraction of lignin and the synthesis of size-controlled LNPs from eucalyptus bark, using an ethanol-organosolv process followed by antisolvent precipitation. By valuing a low-cost waste material, this work also contributes to circular economy and sustainability goals, positioning LNPs as viable bio-based nanomaterials for high-value applications.

Lignin was extracted under non-isothermal conditions at 230 °C using 65% ethanol, resulting in an extraction yield of 49% and purity of 96.07%. The dried lignin was dissolved in ethanol to prepare a precursor solution, which was then added dropwise into deionized water at controlled dilution rates to form nanoparticles, without the use of surfactants or chemical additives. Size control was achieved by adjusting the water-to-solvent ratio during precipitation. Higher water content increased supersaturation, promoting rapid nucleation and the formation of smaller nanoparticles, while lower water content reduced nucleation rates, allowing more particle growth and larger sizes. Dynamic Light Scattering revealed tunable nanoparticle sizes ranging from 148.0 ± 3.2 nm to 274.9 ± 8.1 nm, with polydispersity index values below 0.2, indicating narrow size distributions. Zeta potential measurements confirmed the colloidal stability of the aqueous dispersions. Scanning electron microscopy images show the round shape and confirm the sizes of the produced LNPs.

This environmentally friendly method shows how to transform lignin into uniform, and stable nanoparticles using only ethanol and water. The resulting LNPs are well suited for applications that require precise reproducibility and sustainability.

Thermal analysis is a fundamental approach in materials science for evaluating thermal transitions, degradation mechanisms, and stability. This study explores the application of two key techniques—Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA)—across a diverse range of materials relevant to industrial, scientific, and conservation applications.

DSC and TGA measurements were conducted under controlled inert or oxidative atmospheres using standard protocols. DSC assessed heat flow changes during physical and chemical transitions, while TGA monitored mass variations during thermal treatment. The following materials were examined: (1) neat high-density polyethylene (HDPE) and HDPE/graphene nanocomposites, (2) phenol-formaldehyde (PF) resins used in wood-based panels, (3) thermoelectric compound chromium disilicide (CrSi₂), (4) yellow ochre pigments and mineral phases from cultural heritage samples and (5) bioactive glass–porcelain composites for dental restorations.

DSC revealed characteristic transitions such as melting, crystallization, and glass transitions, with shifts dependent on composition and filler type. TGA of HDPE/graphene systems showed improved thermal stability with increasing graphene content. PF resins exhibited water and formaldehyde release below 260 °C, followed by resin decomposition. CrSi₂ showed high thermal stability with minimal mass loss. Cultural heritage pigments displayed complex thermal behavior linked to multiple mineral components. In dental ceramics, addition of bioactive glass shifted transition temperatures and introduced new crystallization peaks associated with leucite transformation.

DSC and TGA are versatile tools for characterizing thermal behavior across polymers, composites, ceramics, and mineral-based systems. Their combined application enables a comprehensive understanding of processing conditions, material stability, and functional performance. These techniques are essential for materials development, manufacturing optimization, and heritage conservation strategies.

The advancement of biochemical sensing technologies relies heavily on the development of nanostructured sensors with superior electrochemical performance. In this work, a high-sensitivity, non-enzymatic L-lactic acid sensor was fabricated by coating a screen-printed carbon electrode with copper using the glancing angle deposition (GLAD) technique. During deposition, the substrate was positioned at an 80° tilt relative to the target while undergoing continuous rotation. Coatings were applied for 10 and 15 minutes at rotation speeds of 0 rpm and 45 rpm. Electrochemical characterization revealed a fast response and high sensitivity toward L-lactic acid. The GLAD-modified sensor (45 rpm, 15 minutes) achieved an active surface area of 14.14 mm²—an 11.1% increase compared to the apparent surface area of the unmodified carbon electrode (12.57 mm²), as determined using the Randles–Sevcík equation.

Atomic force microscopy confirmed a 16.3% increase in surface area, attributed to the growth of smaller nanostructures during rotation. Scanning electron microscopy images showed a porous, stacked morphology composed of copper (Cu) and copper oxide (CuO). The sensor detected L-lactic acid across the 0.75–10 mM range, with a sensitivity of 3.98 μA/mM and a detection limit of 0.56 μM. These results demonstrate that copper nanostructures engineered via GLAD can substantially enhance the selectivity and sensitivity of electrochemical sensors, offering a promising route for the development of next-generation sensing platforms.

The oxygen evolution reaction (OER) is a critical half-reaction in electrochemical water splitting; however, its sluggish kinetics necessitate the development of efficient, stable, and low-cost electrocatalysts. Transition-metal-based perovskite oxides are promising candidates owing to their earth-abundant composition, structural tunability, and versatile surface chemistry. In this study, SrCo_0.6Mn_0.4O₃ (SCM) perovskite oxides were synthesized via four different methods, such as solid state (SCM-SS), sol–gel (SCM-SG), co-precipitation (SCM-CP), and the hydrothermal method (SCM-HT). XRD and FESEM analyses confirmed the formation of crystalline perovskite oxides with distinct morphologies and crystallinities, directly influencing their electrocatalytic performance. Among all the samples, SCM-SS demonstrated the best activity, requiring an overpotential of 1.07 V at a current density of 10 mA cm^-2 and exhibiting the smallest Tafel slope of 145.82 mV dec^-1 in 1 M KOH. The overpotential values followed the following order: SCM-SS (1.07 V), SCM-SG (1.20 V), SCM-HT (1.22 V), and SCM-CP (1.35 V). Similarly, the Tafel slopes were SCM-SS (145.82 mV dec^-1), SCM-CP (151.46 mV dec^-1), SCM-SG (153.97 mV dec^-1), and SCM-HT (226.55 mV dec^-1). These findings highlight that the synthesis method plays a decisive role in tailoring crystallinity, morphology, and the electrocatalytic activity of SCM perovskites, offering valuable guidelines for designing next-generation water-splitting catalysts. This work contributes to advancing Sustainable Development Goal 7 by promoting clean energy technologies and supports Sustainable Development Goal 13 by addressing climate challenges through the development of efficient, sustainable electrocatalysts.

The assembly of nanoparticles into mesoscopic structures, known as Superparticles (SPs), leads to emergent properties arising from interactions among their components [1, 2]. Indeed, various types of nanoparticles, ranging from metal chalcogenide and perovskite quantum dots (QDs) to metal nanoparticles and magnetite nanocubes, can act as functional building blocks for artificial solids displaying unique properties that transcend those of their constituents. Within this landscape, SPs based on plasmonic metal nanoparticles [3-5] have attracted significant interest owing to the unique coupling effects between the plasmonic fields of the constituent nanoparticles, holding great promise for several applications including ultra-efficient surface-enhanced Raman scattering (SERS) [6,7]. Despite this promising outlook, the understanding of the fundamental factors driving the behavior of metal SPs is still incomplete.

Here, we assembled gold nanoparticles (AuNPs) into 200-300 nm SPs with varying interparticle distances. After performing a structural characterization of the resulting SPs, we leveraged transient absorption spectroscopy (TA) and transient absorption microscopy (μPP) to unravel their ultrafast photophysics. Our results shed light on the role of interactions between plasmon resonances in determining the overall optical response of metal SPs. In fact, both spectral shape and kinetics show a dependance upon the interparticle distance, revealing the emergence of a collective response of the SP to photoexcitation due to interactions between the constituent nanoparticles, as also highlighted by numerical field enhancement simulations. The results pave the way to the engineering of functional metal-based superstructures for a variety of possible applications in photonics and optoelectronics.

[1] ACS Nano 2020, 14, 10, 13806–13815.

[2] Nat Synth, 2023, 10.1038/s44160-023-00407-2.

[3] Chem. Rev. 2020, 120, 2, 464–525.

[4] Nanoscale Adv., 2020, 2, 3764-3787.

[5] Nat. Comm, 11, 2771, 2020.

[6] Adv. Funct. Mater. 2020, 30, 2005400.

[7] Nanoscale, 2019, 11, 17444-17459.

The increasing demand for compact, flexible, and transparent energy storage devices has stimulated intensive research on advanced electrode materials. Transition metal oxides are among the most promising candidates, with vanadium oxide (VOₓ) attracting particular interest due to its wide range of accessible oxidation states and ability to form non-stoichiometric phases. In this work, VOₓ thin films were prepared on ITO-coated glass substrates by DC reactive sputtering under different oxygen pressures, without applying external heating. Structural and optical characterization by SEM and UV-Vis spectroscopy confirmed the formation of smooth, uniform films with a thickness of about 100 nm and no detectable porosity. XPS analysis revealed that varying the oxygen pressure during deposition allows manipulation of the vanadium oxidation states, thereby tuning the electronic structure of the films. This adjustment in oxidation states directly influenced their electrochemical response. Electrochemical testing in 1 M Na₂SO₄ revealed excellent capacitive behavior: cyclic voltammetry showed a volumetric capacitance of 143 F/cm³ at 50 mV/s, while galvanostatic charge–discharge experiments demonstrated stable cycling at 1 mA/cm². These findings highlight reactive sputtering as a scalable method to produce VOₓ thin films with controlled structural and electronic properties. The observed correlation between oxidation state distribution and electrochemical behavior underscores their strong potential as electrodes for supercapacitor applications.

The pursuit of sustainable and lead-free alternatives for piezoelectric materials has motivated the development of new synthesis strategies with minimal environmental impact. In this study, we report an eco-friendly approach for fabricating piezoactive nanostructures based on zinc oxide (ZnO) doped with silver (Ag) and lithium (Li).

The nanostructures were synthesized via a low-temperature hydrothermal method directly on metallic substrates (platinum and titanium foils) previously coated with a ZnO seed layer obtained through sol–gel spin coating. The hybrid system was further encapsulated with a polymer layer to ensure mechanical stability and compatibility for device integration. Comprehensive morphological characterization was performed using atomic force microscopy and scanning electron microscopy, confirming the successful growth of well-aligned doped ZnO nanostructures. The piezoelectric performance of the samples was evaluated through measurements of the direct piezoelectric coefficient (d₃₃).

The results demonstrated that the incorporation of dopant ions not only preserved but also enhanced the piezoelectric activity of the ZnO structures, indicating that the synthesis route is both efficient and environmentally responsible. This work highlights the potential of Ag- and Li-doped ZnO nanostructures, prepared under green processing conditions, for obtaining large-area piezoelectric materials. The combination of low-cost synthesis, ecological benefits, and functional piezoelectric response suggests that this approach represents a promising pathway toward sustainable materials design for applications in energy harvesting.