The green synthesis approach offers an efficient route for converting waste into valuable chemicals while minimising energy consumption and environmental impact. In this context, the pivotal roles of heterogeneous catalysis and nanocatalysis are evident, as they provide stable and tunable active sites that enable selective and sustainable transformations in industrial processes. In order to develop more environmentally friendly catalytic systems, novel palladium-based catalysts have been immobilised within soy protein cryogels. These bio-based materials address the major drawbacks of traditional palladium catalysts, including limited reusability, structural instability, and metal leaching. The porous cryogel matrix creates a confined microenvironment that ensures homogeneous dispersion and stabilisation of palladium species at a concentration of 2 mmol%, thereby enabling effective nanocatalysis in Suzuki–Miyaura, Sonogashira, and Heck reactions.

A diverse library of C–C coupled products was synthesised under mild conditions (80 °C) in alcoholic and aqueous media, achieving excellent yields of up to 99%. The findings of the recyclability studies demonstrated the remarkable structural integrity and reusability of the catalyst over multiple cycles, with only minimal reductions in efficiency after ten runs. The protein network within the cryogel facilitates facile recovery of the catalyst, whilst also modulating its activity through spatial confinement effects. A series of computational investigations were conducted in order to further elucidate the structural and electronic characteristics that underpin the performance of the catalyst. The system's low-cost synthesis, high stability, and scalability make it a promising green alternative for industrial heterogeneous catalysis and nanocatalysis.

Perovskite oxides have gained significant attention as bifunctional electrocatalysts for water splitting due to their tunable electronic structures and robust stability. Our work focuses on designing transition metal-based perovskite oxide catalysts, which directly addresses the limitations of traditional noble-metal catalysts by offering improved activity, stability, and affordability. In this work, we synthesized SrCoO₃ (SCO) perovskite oxides via a sol–gel method followed by thermal treatment at various calcination temperatures (800 °C, 900 °C, and 1000 °C) to investigate their bifunctional electrocatalytic activity toward the hydrogen and oxygen evolution reactions (HER and OER). X-ray diffraction analysis confirmed the formation of a well-crystallized rhombohedral perovskite phase (space group R32:H), with impurity phases of Co₃O₄ and SrCO₃ observed at lower temperatures and diminishing at higher calcination temperatures. FESEM imaging revealed a progressive morphological evolution, where increasing the calcination temperature enhanced grain growth, surface smoothness, and particle densification. Electrochemical measurements demonstrated that the sample calcined at 1000 °C (SCO1000) exhibited superior HER activity with a low overpotential of 473 mV at 10 mA cm^-2 and a Tafel slope of 112.62 mV dec^-1, outperforming SCO900 and SCO800. Conversely, for OER, the SCO800 sample showed the best performance, delivering an overpotential of 420 mV at 10 mA cm^-2 and the lowest Tafel slope of 90.59 mV dec^-1. These results indicate that thermal treatment not only influences the crystallinity and phase purity but also critically modulates the surface structure and electrochemical behavior of SCO, enabling selective optimization for HER or OER through calcination temperature control.

Black titania has captured the attention of scientists in various fields of materials science due to its intriguing electronic properties, which stem from a high level of surface defects. These defects yield a heavily disordered local structure with multiple local charges that elicit a high degree of chemical activity and electronic transport. Due to their structural and electronic properties, black titania composites have been explored for various energy-related applications. Moreover, black titania exhibits favourable interactions with biopolymers such as cellulose and chitin nanocrystals—the first and second most abundant biopolymers on Earth—due to its different functional groups. That and their atomic arrangement make them ideal for battery or supercapacitor applications. However, there remains significant room for experimentation and optimization of composite films that combine the advantages of both black titania and biopolymers. With this underlying motivation, we report the fabrication and optimization of black titania and biopolymer films aimed at energy storage applications. Optimization was needed in order to improve their quality and mechanical properties. Hydrothermal treatment was then used to obtain the black titania composites. The final products were characterized using various techniques, including Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and Raman spectroscopy, among others. The results also include the evaluation of the film for potential energy storage applications.

In recent years, considerableattention has been paid to synthesizing metal oxide nanocomposites because of their distinctive physicochemical characteristics, which have applications in biomedicine, environmental remediation, sensing, and catalysis. Various metal oxide nanoparticles, including FeO, ZnO, TiO2, In2O3, SnO2, SiO2, NiO, CeO2, and CuO, are used for the synthesis of nanocomposites. Among these, zinc oxide (ZnO) nanoparticles have garnered considerable interest due to their unique characteristics. Adding organic ligands, especially thiosemicarbazides and their derivatives, enhances its stability, chemical reactivity, biocompatibility, solubility, etc. Ultrasonic-assisted methods have become a viable, environmentally friendly, and effective approach for producing nanocomposites with unique characteristics among various synthesis approaches. This process utilizes ultrasonic cavitation to facilitate the efficient coordination of thiosemicarbazide derivatives while enabling fast nucleation, uniform dispersion, and fine particle size control of metal oxides. Various characterisation methods, including Fourier transform Infra-Red (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX), and Ultraviolet–visible (UV-Vis), have been used to confirm the synthesis of metal oxide nanocomposites functionalized with ligands that exhibit promising physicochemical and biological properties. This study focuses on the synthesis processes, characterization, and applications of ZnO NPs conjugated with substituted thiosemicarbazides in environmental remediation, catalysis, anticancer therapy, and antimicrobial therapy.

Abstract

ZnSnO₃ nanoparticles were successfully synthesized via a chemical precipitation method employing zinc chloride (ZnCl₂) and tin(IV) chloride pentahydrate (SnCl₄·5H₂O) as precursor materials. The precipitate was washed, dried, and calcined at 500 °C to enhance crystallinity and ensure stable phase formation. The synthesized nanoparticles were subsequently incorporated into a polyvinylpyrrolidone (PVP) matrix to fabricate flexible composite nanofibers through electrospinning. This technique facilitated the formation of continuous, bead-free nanofibers with uniform morphology, demonstrating suitability for flexible electronic applications. The combination of inorganic ZnSnO₃ nanoparticles with an organic polymer matrix offers a synergistic pathway to enhance both mechanical flexibility and functional performance. Structural analysis using X-ray diffraction (XRD) confirmed the crystalline nature of ZnSnO₃, with no distinct peaks corresponding to the amorphous PVP phase. Fourier-transform infrared (FTIR) spectroscopy revealed characteristic absorption bands of Zn–O and Sn–O stretching vibrations, along with identifiable peaks of PVP, indicating strong interfacial interactions between the nanoparticles and the polymer chains. Field emission scanning electron microscopy (FESEM) images showed smooth nanofibers with diameters ranging from 200 to 400 nm, exhibiting excellent dispersion of nanoparticles without visible agglomeration. These results validate the successful synthesis and integration of ZnSnO₃ within a flexible polymer nanofiber network. The resulting ZnSnO₃/PVP composite exhibits promising structural and morphological features, making it a potential candidate for applications in flexible electronics, nanosensors, and energy-harvesting devices.

The development of perovskite solar cells (PSCs) using sustainable green nanomaterials has indeed shown great promise in the renewable energy sector due to its high efficiency, low manufacturing cost, and potential for commercial viability. However, there are some issues that need to be addressed to make PSCs commercially available for the development of sustainable technology. These issues include stability, toxicity, scalability, and reliability. In this context, titanium dioxide (TiO₂) have been widely investigated as an electron transport layer (ETL) in PSCs due to its promising properties, including its high electron mobility and excellent stability. However, despite these advantages, TiO₂ also has some limitations, such as poor charge transport properties, a high rate of electron-hole recombinations, and poor visible light response due to its wide bandgap of ~3.2eV, which lowers the current and voltage densities of the solar cell. Researchers have explored ways of optimizing the morphology of TiO₂ with graphene nanomaterials, which can help in enhancing the performance and stability of PSCs because of their exceptional electrical conductivity, high electron mobility, large surface area, and excellent mechanical properties. This review summarizes the ongoing research in the field of the synthesis of graphene-based TiO₂ nanomaterials, reported by different authors across the globe as an ETL for PSCs. Existing issues and challenges associated with its synthesis is also highlighted in this paper. We have also reviewed the structural, morphological, optical, and photovoltaic properties of graphene-based TiO₂ nanomaterials.

This study presents an investigation into the structural, morphological, vibrational, optical, and magnetic properties of holmium-doped β-Ga₂O₃ nanoparticles synthesized via the solid-state combustion method. X-ray diffraction (XRD) and Williamson–Hall (W–H) analysis confirm the substitution of Ho³⁺ (0.90 Å) for Ga³⁺ (0.62 Å), introducing substantial lattice strain due to the ionic size mismatch. This strain leads to a reduction in crystallite size at 1 wt% doping, while partial strain relaxation at higher concentrations (2–3 wt%) results in moderate grain coarsening. However, the sizes remain below those of the undoped sample. FESEM analysis reveals that grain size follows a similar trend, with morphology characterized by quasi-spherical, polydispersed grains exhibiting agglomeration and non-uniform distribution, reflecting the competing effects of lattice distortion, dopant accommodation, and defect dynamics. Energy-dispersive X-ray spectroscopy (EDS) confirms uniform Ho³⁺ distribution without secondary phase segregation. FTIR spectra exhibit blue-shifted Ga–O vibrational modes, indicating enhanced bond stiffness and structural distortion. UV–Vis diffuse reflectance spectra reveal a doping‑dependent Burstein–Moss shift, corresponding to bandgap widening caused by increased carrier concentration and strain‑altered electronic states. Absorption bands at 361, 419, 454, 487, 643, and 801 nm arise from Ho³⁺ intra‑4f transitions, confirming substitutional incorporation. Photoluminescence (PL) spectra exhibit broad visible emission spanning 400–600 nm, with peaks at 427, 467, and 518 nm, corresponding to the violet, blue, and bluish-green regions. A systematic quenching in PL intensity is observed with increasing Ho³⁺ concentration, attributed to enhanced non-radiative recombination via defect centers. Magnetic measurements using vibrating sample magnetometry (VSM) reveal a transition from intrinsic diamagnetism in undoped β‑Ga₂O₃ to weak ferromagnetism in Ho³⁺‑doped samples, arising from the magnetic moment of Ho³⁺ ions and defect‑mediated exchange interactions. To the best of our knowledge, this is the first report of substitutional Ho³⁺ doping in β‑Ga₂O₃ via solid‑state combustion synthesis. The tunable multifunctionality observed in structural, optical, and magnetic domains highlights the potential of Ho³⁺‑doped β‑Ga₂O₃ for future optoelectronic and spintronic applications.

The formation of a biomolecular corona significantly influences the biological identity and behavior of nanomaterials, affecting cellular uptake, toxicity, and biodistribution. Protein analysis is a central tool in corona characterization, providing insight into the composition and affinity of proteins adsorbed onto nanomaterial surfaces. However, standard protocols often fail to account for the unique physicochemical properties of advanced nanomaterials, such as graphene oxide (GO), which can interfere with protein elution and lead to biased or incomplete analyses. To address these challenges, we investigated the limitations of conventional SDS-based elution methods for protein corona analysis on GO. We compared these to an improved protocol utilizing chaotropic agents, urea, and thiourea in a stepwise extraction process. Protein corona complexes were isolated after incubation with GO and subjected to sequential protein elution using SDS-based or urea/thiourea-based buffers prior to SDS-PAGE and LC-MS/MS analysis. Our findings revealed that SDS-based protocols were insufficient for desorbing strongly bound proteins, particularly those with hydrophobic characteristics. The use of chaotropic agents significantly improved protein recovery, enabling near-complete elution from the GO surface. Importantly, the improved method revealed protein populations underrepresented in standard protocols, demonstrating its enhanced capability to recover high-affinity, hydrophobic corona constituents. This study underscores the need to tailor biomolecular corona characterization protocols to specific material properties. The improved method offers a more accurate and reproducible strategy for analyzing the protein corona on GO, addressing critical gaps in current nanosafety practices. Standardizing such optimized protocols is essential for ensuring the reliability of in vitro assessments and for promoting the safe and sustainable application of Ad-NMs in biological and environmental contexts.

Introduction. Diesel cold-start engines still account for the majority of regulated NOx and CO emissions because conventional lean NOx traps (LNTs) do not reach the light-off state until > 250 °C and rely on costly Pt/Pd/Rh. We report a multilayer LNT stack that replaces noble metals with a low-cost Surrogate Noble Metal (SNM) nitride and embeds a pyroelectric sheet that harvests the exhaust’s natural 80 → 180 °C ramp to deliver a self-generated 0.3–0.4 V surface pulse. This “pseudocapacitor” kick-starts electropromotion, enabling simultaneous NOx and CO conversion from < 200 °C through full-load conditions.

Methods. A 15 nm SNM nitride was high-power-impulse-sputtered onto 8 mol % YSZ monolith channels and over-coated with a 5 µm BaO/Ce₀.₇Zr₀.₃O₂ storage layer. A 200 µm Ca-doped YMnO₃ sheet, hot-pressed between the monolith and a stainless-steel heat spreader, generated the pyroelectric voltage during temperature transients. Catalytic performance was assessed under alternating lean (12 % O₂) and rich (1 % CO) feeds in a transient flow reactor, while operando X-ray absorption (SNM K-edge) and DRIFTS monitored metal redox and nitrate dynamics over 40 lean/rich cycles.

Results. The pyroelectric pulse reduced SNM^δ+ to metallic SNM within 15 s, drove K⁺ migration to the SNM/oxide interface, and doubled CO adsorption entropy. Consequently, ≥ 90 % NOx and 75 % CO conversion were achieved at 180 °C—22 % higher than a Pt-Ba/Al₂O₃ benchmark while using 60 % less precious metal overall. Durability tests (40 cycles, 650 °C regenerations) showed only 8 % storage capacity loss and < 3 nm particle growth, establishing the first all-temperature dual-redox LNT that is self-powered and cost-efficient.

Iron oxi(hydroxi)des are known to be efficient sorbents toward arsenic species, thanks to the formation of complexes of the inner sphere, through ligand exchange of surface -OH₂ and -OH^. with the arsenic species in the coordination sphere of the structural Fe atoms.[1] Recently, we compared the sorption ability of different iron oxi(hydroxi)des, namely akaganeite (β-FeOOH), ferrihydrite (referred to as Fe₅HO₈∙4H₂O), and maghemite (γ-Fe₂O₃, as a bare and silica-based composite), toward arseniate/arsenite species in spiked aqueous solutions.[2] Akaganeite was proved to be the best sorbent for arseniate anions (89 mg g -1 at pH₀ 3, 52 mg g^-1 at pH₀ 8) and also an efficient one for arsenite species (91 mg g^-1 at pH₀ 3–8), thanks to its high positive surface charge (measured by Electrophoretic Light Scattering, ELS, ≈30 mV) and high surface area (determined by N₂ physisorption, ≈200 m² g^-1 ). To investigate the adsorption process and the interaction between arseniate/arsenite and akageneite, different methods, such as powder X-ray diffraction (PXRD), infrared spectroscopy (FTIR-ATR), transmission electron microscopy also in high resolution (HRTEM) and coupled with chemical probes (EDX-EELS), X-ray photoelectron spectroscopy (XPS), X-ray absorption (XAS), and DC magnetometry, were adopted. None of these techniques were able to detect any changes in the sorbent properties upon adsorption, except for FTIR-ATR and DC magnetometry. In particular, the interaction between akageneite and arseniate species was found to produce a distinctive change in the magnetism of the sorbent, with the appearance of a second band in the temperature profile of the magnetisation, whose associated intensity increased with increasing adsorbate amount. This work demonstrates the high sensitivity of DC magnetometry in exploring surface phenomena in iron-bearing materials.

[1] A. Jain, et al Environ. Sci. Technol. 1999, 33, 1179–1184.

[2] M. Sanna Angotzi, et al, Nanomaterials 2022, 12, 326, 1-22.