Search Results (414)

Developments of nanostructured materials have a significant impact in various areas, such as energy technology and biomedical use. Examples include solar cells, energy management, environmental control, bioprobes, tissue engineering, biological marking, cancer diagnosis, therapy, and drug delivery. Currently, researchers are designing multifunctional nanodrugs that combine in vivo imaging (using fluorescent nanomaterials) with targeted drug delivery, aiming to maximize therapeutic efficacy while minimizing toxicity. These fascinating nanoscale “magic bullets” should be available in the near future. Inorganic nanovehicles are flexible carriers to deliver drugs to their biological targets. Most commonly, mesoporous nanostructured silica, carbon nanotubes, gold, and iron oxide nanoparticles have been thoroughly studied in recent years. Opposite to polymeric and lipid nanostructured materials, inorganic nanomaterial drug carriers are unique because they have shown astonishing theranostic (therapy and diagnostics) effects, expressing an undeniable part of future use in medicine. This review summarizes research from development to the most recent discoveries in the field of nanostructured materials and their applications in drug delivery, including promising metal-based complexes, platinum, palladium, ruthenium, titanium, and tin, to tumor cells and possible use in theranostics. Full article

Cocktail-type catalysis represents a significant shift in the understanding of catalytic processes, recognizing that multiple interconverting species—such as metal complexes, clusters, and nanoparticles—can coexist and cooperate within a single reaction environment. Originating from mechanistic studies on palladium-catalyzed systems, this concept challenges the classical division between homogeneous and heterogeneous catalysis. Instead, it introduces a dynamic framework where catalysts adapt and evolve under reaction conditions, often enhancing efficiency, selectivity, and durability. Using advanced spectroscopic, microscopic, and computational techniques, researchers have visualized the formation and transformation of catalytic species in real time. The cocktail-type approach has since been extended to platinum, nickel, copper, and other transition metals, revealing a general principle in catalysis. This approach not only resolves long-standing mechanistic inconsistencies, but also opens new directions for catalyst design, green chemistry, and sustainable industrial applications. Embracing the complexity of catalytic systems may redefine future strategies in both fundamental research and applied catalysis. Full article

Hexavalent chromium [Cr(VI)] is a hazardous environmental contaminant, and palladium nanoparticles (PdNPs) have shown promise as catalysts for its reduction. This study explores the primary factor influencing the catalytic performance of PdNPs in Cr(VI) reduction by investigating the crystal structure and composition of PdNPs in fungal-based catalysts. Five Pd-loaded catalysts were synthesized by treating fungal biomass with different chemical reagents, resulting in varying Pd(0) contents. The nanoparticle morphology, chemical states, and functional group interactions during Pd adsorption and reduction were investigated using multiple analytical techniques. The results showed that fungal hyphae remained structurally intact throughout the treatment process. PdNPs smaller than 2 nm were observed, with both Pd(0) and PdO present. The proportion of Pd(0) ranged from 6.4% to 37.2%, depending on the chemical reagent used. In addition, functional groups such as phosphate, amine, hydroxyl, and carboxyl were found to play key roles in palladium binding, underscoring the importance of surface chemistry in the adsorption and reduction process. A strong positive correlation was observed between the Pd(0) content and catalytic activity. Notably, the NCPdSF sample (palladium-loaded biomass treated with sodium formate) exhibited the highest Pd(0) content of 59.2% and achieved the most effective Cr(VI) reduction. These results suggest that Pd(0) content is a key determinant of catalytic efficiency in Cr(VI) reduction and that optimizing chemical treatments to enhance Pd(0) levels can substantially improve catalyst performance. Full article

In this work, the effect of the palladium precursor on the Oxygen Reduction Reaction (ORR) performance of lignin-based electrospun carbon fibers was studied. The fibers were spun from a lignin-ethanol solution free of any binder, where different Pd salts were added at two concentration levels. The system implemented to perform the spinning was a coaxial setup in which the internal flow contains the precursor dispersion with the metallic precursor, and ethanol was used as external flow to help fiber formation and prevent drying before generating the Taylor cone. The obtained cloths were thermostabilized in air at 200 °C and carbonized in nitrogen at 900 °C. The resulting carbon fibers were characterized by physicochemical and electrochemical techniques. The palladium precursor significantly affects nanoparticle distribution and size, fiber diameter, pore distribution, surface area and electrochemical behavior. The fibers prepared with palladium acetylacetonate at high Pd loading and carbonized at 900 °C under a CO₂ atmosphere showed high mechanical stability and the best ORR activity, showing near total selectivity towards the 4-electron path. These features are comparable to those of the commercial Pt/C catalyst but much lower metal loading (10.6 wt.% vs. 20 wt.%). The most promising fibers have been evaluated as cathodes in a zinc–air battery, delivering astonishing stability results that surpassed the performance of commercial Pt/C materials in both charging and discharging processes. Full article

A separable bamboo-like carbon nanotube-based catalyst was prepared by the spherfication method using sodium alginate and nickel. The spheres were carbonized and then decorated with palladium nanoparticles before they were tested in nitrobenzene hydrogenation. The test was repeated with five different commonly used solvents (methanol, ethanol, isopropanol, tetrahydrofuran, and acetonitrile). According to the results, polar solvents showed a significantly higher aniline yield than the more apolar solvents and exceptional results were reported for ethanol (~100%). The catalyst was reused two more times (four hours each) to check the Pd leaching where the spheres kept their shape (despite the high mechanical friction caused by the mixer) and only a relatively low Pd amount was lost (5.48 rel.%). The catalyst was easily retrievable. Full article

The importance and challenges of ethylene detection based on combustion-type low-cost commercial sensors for agricultural and industrial applications are well-established. This work summarizes the significant progress in ethylene detection based on an innovative Gas Metal Oxide Semiconductor (GMOS) sensor and a new catalytic composition of metallic nanoparticles. The paper presents a study on ethylene and ethanol sensing using a miniature catalytic sensor fabricated by Complementary Metal Oxide Semiconductor–Silicon-on-Insulator–Micro-Electro-Mechanical System (CMOS-SOI-MEMS) technology. The GMOS performance with bimetallic palladium–platinum (Pd-Pt) and monometallic palladium (Pd) and platinum (Pt) catalysts is compared. The synergetic effect of the Pd-Pt catalyst is observed, which is expressed in the shift of combustion reaction ignition to lower catalyst temperatures as well as increased sensitivity compared to monometallic components. The optimal catalysts and their temperature regimes for low and high ethylene concentrations are chosen, resulting in lower power consumption by the sensor. Full article

Supported Pd-based catalysts have been widely applied in the hydrogenation of specific functional groups. Recent trends have focused on employing Pd-based heterogeneous catalysts supported on inorganic nanotubes, wherein inner surface functionalization modulates both palladium nanoparticle (Pd-NP) dispersion and the interaction between reactants and the catalyst surface, thereby influencing catalytic properties. This study aims to develop a catalytic system using amine-lumened halloysite nanotubes immobilizing Pd-NPs (Pd/HNTA) as catalysts for hydrogenation reactions. The formation of Pd-NPs within the organo-functionalized lumen—modified by 3-aminopropyltrimethoxysilane—is confirmed by transmission electron microscopy (TEM) imaging, which reveals a particle size of 2.2 ± 0.4 nm. For comparison, Pd-NPs supported on pristine halloysite (Pd/HNTP) were used as control catalysts, displaying a metal particle size of 2.8 ± 0.8 nm and thereby demonstrating the effect of organic functionalization on the halloysite nanotubes. Both catalysts were employed in the hydrogenation of furfural (FUR) and nitrobenzene (NB) as model reactions. Pd/HNTA demonstrated superior catalytic performance for both substrates, with TOF values of 880 h⁻¹ for FUR and 946 h⁻¹ for NB, and selectivities exceeding 98% for tetrahydrofurfuryl alcohol (THFOH) and aniline (AN), respectively. However, recyclability studies displayed that Pd/HNTA was deactivated at the 10 catalytic cycles during the hydrogenation of FUR, whereas, in the hydrogenation of NB, 5 catalytic cycles were achieved with maximum conversion and selectivity at 360 min. These results revealed that the liquid-phase environment plays a pivotal role in catalyst stability. In the hydrogenation of NB, the coproduction of H₂O adversely affects the interaction between the Pd particles and the inner amine-modified surface, increasing the deactivation of the catalyst with reuse. Thus, the Pd/HNTA catalyst holds significant promise for the development of noble-metal-based catalysts and their application in the transformation of other reducible organic functional groups via hydrogenation reaction. Full article

This study presents a sustainable, environmentally friendly synthetic route for the production of key intermediates in losartan using palladium nanoparticles (PdNPs) derived from a brown seaweed, Sargassum incisifolium, as a recyclable nanocatalyst. A key intermediate, biaryl, was synthesized with an excellent yield (98%) via Suzuki–Miyaura coupling between 2-bromobenzonitrile and 4-methylphenylboronic acid, catalyzed using bio-derived PdNPs under mild conditions. Subsequent bromination using N-bromosuccinimide (NBS) under LED light, followed by imidazole coupling and tetrazole ring formation, allowed for the production of losartan with an overall yield of 27%. The PdNP catalyst exhibited high stability and recyclability, as well as strong catalytic activity, even at lower loadings, and nitrosamine formation was not detected. While the overall yield was lower than that of traditional industrial methods, this was due to the deliberate avoidance of the use of toxic reagents, hazardous solvents, and protection/deprotection steps commonly used in conventional routes. This trade-off marks a shift in pharmaceutical process development, where environmental and safety considerations are increasingly prioritized in line with green chemistry and regulatory frameworks. This study provides a foundation for green scaling up strategies, incorporating sustainability principles into drug synthesis. Full article

Pd-WO₃ coatings on porous silicon (PSi) substrates are engineered to enhance interfacial charge transfer and surface reactivity through atomic-scale structural tailoring. This study combines first-principles calculations and experimental characterization to elucidate how Pd nanoparticles (NPs) optimize the coating’s electronic structure and environmental stability. The hierarchical PSi framework with uniform nanopores (200–500 nm) serves as a robust substrate for WO₃ nanorod growth (50–100 nm diameter), while Pd decoration (15%–20% surface coverage) strengthens Pd–O–W interfacial bonds, amplifying electron density at the Fermi level by 2.22-fold. Systematic computational analysis reveals that Pd-induced d-p orbital hybridization near the Fermi level (−2 to +1 eV) enhances charge delocalization, optimizing interfacial charge transfer. Experimentally, these modifications enhance the coating’s response to environmental degradation, showing less than 3% performance decay over 30 days under cyclic humidity (45 ± 3% RH). Although designed for gas sensing, the coating’s high surface-to-volume ratio and delocalized charge transport channels demonstrate broader applicability in catalytic and high-stress environments. This work provides a paradigm for designing multifunctional coatings through synergistic interface engineering. Full article

A naturally derived silicate, diatomaceous earth has been endowed with magnetic properties by depositing magnetite nanoparticles on its surface. Palladium crystallites were created on the resulting magnetizable catalyst support. The support provided high specific surface area with high porosity which were ideal for the binding of both the magnetic particles and the palladium. The catalyst was successfully tested in the hydrogenation of benzophenone in three different solvents (methanol, ethanol, and isopropanol). Significant differences in catalytic activity were observed, allowing selective production of benzhydrol (BH) or diphenylmethane (DPM) by a simple solvent change. Beside the excellent selectivity, the featured catalyst also provided an easy and fast method for catalyst recoverability using a simple magnet. Full article

Graphene film has excellent electrical conductivity and flexibility, with which it can be used as a versatile substrate to load active species to construct free-standing electrochemical sensors. In this work, Pd nanoparticle-decorated N-doped porous graphene film (Pd/NPGF) was prepared by a simple and mild strategy to enhance the electrochemical behavior of graphene film-based free-standing electrodes. The morphological structure and surface component of the Pd/NPGF were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectra and X-ray photoelectron spectroscopy measurements. The results revealed that the Pd/NPGF contained abundant pores and uniformly dispersed Pd nanoparticles, which could bring a favorable electrochemical response. Due to the synergetic effects of abundant pores, uniform Pd nanoparticles and the substitutional doping of the graphene framework with N, the novel free-standing Pd/NPGF electrode provides a high active site exposure, a high specific area and fast electron/mass diffusion during electrochemical reactions. Considering the favorable flexibility and excellent electrical conductivity of Pd/NPGF, we selected hydrogen peroxide, a significant biomarker, as a model to investigate its electrochemical performance in neutral conditions. The electrochemical biosensor based on the Pd/NPGF electrode exhibited enhanced activity relative to the NPGF and porous graphene film (PGF) with different concentrations of H₂O₂. The Pd/NPGF electrode displayed a high sensitivity (176.7 μA·mM⁻¹·cm⁻²), a large linear range from 5 μM to 36.3 mM, a low limit of detection (LOD) of 2.3 μM, excellent stability and a short response time, all of which qualify the Pd/NPGF electrode for a promising sensor for H₂O₂ sensing. Full article

The availability of water-soluble nanoparticles allows catalytic reactions to occur in highly desirable green environments. The catalytic activity and selectivity of water-soluble palladium nanoparticles capped with 6-(carboxylate)hexanethiolate (C6-PdNP) and 5-(trimethylammonio)pentanethiolate (C5-PdNP) were investigated for the reduction of 4-nitrophenol, the oxidation of α,β-conjugated aldehydes, and the C-C coupling of phenylboronic acid. The study showed that between the two PdNPs, C6-PdNP exhibits better catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride and the selective oxidation of conjugated aldehydes to conjugated carboxylic acids. For the latter reaction, molecular hydrogen (H₂) and H₂O act as oxidants for the surface palladium atoms on PdNPs and conjugated aldehyde substrates, respectively. The results indicated that the competing addition activities of Pd-H and H₂O toward the π-bond of different unsaturated substrates promote either reduction or oxidation reactions under mild conditions in organic solvent-free environments. In comparison, C5-PdNP exhibited higher catalytic activity for the C-C coupling of phenylboronic acid. Gas chromatography–mass spectrometry (GC-MS) was mainly used as an analytical technique to examine the products of catalytic reactions. Full article

Liquid organic hydrogen carriers (LOHCs) are recognized as promising sustainable hydrogen (H₂) carriers due to their high volumetric capacity and ability to store H₂ at ambient conditions, eliminating the need for energy-intensive liquefaction or compression processes associated with H₂ or ammonia gas. One of the main current drawbacks, however, is LOHCs’ high energy demand for H₂ release. This work presents the photo-induced liberation of H₂ from formic acid (FA) as a liquid H₂ carrier, using visible light and well-established 5 wt% palladium nanoparticles supported over carbon (Pd/C). We show that low-power light-emitting diodes (LEDs) produced higher gas flow than their thermal baseline (35 $°$C), with 27.2 mL/min and 7.72 mL/min, respectively. Further, the rate of gas evolved with light intensity, catalyst loading, and the concentration of FA. Light-induced dehydrogenation shows similar deactivation as the known thermal mechanisms, such as the decreased Pd²⁺/Pd⁰ ratio and Pd nanoparticle agglomeration. Hence, these observations suggest a photothermal mechanism, whereby the LED provides heat efficiently absorbed by the Pd/C catalyst and enhanced by Pd’s ability to absorb light, thereby driving the FA dehydrogenation reaction at ambient conditions. Full article

(1) Context: Cancer is still a major problem worldwide, and traditional therapies like radiation and chemotherapy often fail to alleviate symptoms because of side effects, systemic toxicity, and mechanisms of resistance. Beneficial anticancer effects that spare healthy tissues are made possible by the distinctive redox characteristics of noble metal complexes, especially those containing palladium, gold, silver, and platinum. (2) Methods: The redox processes, molecular targets, and therapeutic uses of noble metal complexes in cancer have been the subject of much study over the last 20 years; novel approaches to ligand design, functionalization of nanoparticles, and tumor-specific drug delivery systems are highlighted. (3) Results: Recent developments include Pt(IV) prodrugs and terpyridine-modified Pt complexes for enhanced selectivity and decreased toxicity; platinum complexes, like cisplatin, trigger reactive oxygen species (ROS) production and DNA damage. Functionalized gold nanoparticles (AuNPs) improve targeted delivery and theranostic capabilities, while gold complexes, particularly Au(I) and Au(III), inhibit redox-sensitive processes such as thioredoxin reductase (TrxR). (4) Conclusions: Ag(I)-based compounds and nanoparticles (AgNPs) induce DNA damage and mitochondrial dysfunction by taking advantage of oxidative stress. As redox-based anticancer medicines, noble metal complexes have the ability to transform by taking advantage of certain biochemical features to treat cancer more effectively and selectively. Full article

Palladium nanoparticles (PdNPs) are transforming the landscape of modern catalysis and offer sustainable and efficient alternatives to traditional catalysts for cross-coupling reactions. Owing to their exceptional surface area-to-volume ratio, PdNPs exhibit superior catalytic activity, selectivity, and recyclability, making them ideal for greener chemical processes. Recent innovations have focused on improving the stability and reusability of PdNPs through environmentally benign approaches, such as water-based reactions, renewable stabilizers, and magnetic nanoparticle supports. Advances in catalyst design, including PdNP immobilization on magnetic nanosilica for enhanced recyclability in Suzuki–Miyaura reactions, nitrogen-doped carbon nanosheets achieving up to ninefold improvements in turnover frequencies, and biodegradable biopolymer matrices that reduce environmental impact, have effectively addressed key challenges such as catalyst leaching, support degradation, and agglomeration. The shift from conventional catalysis to these cutting-edge nanocatalytic techniques signifies a critical movement toward sustainable chemistry, positioning PdNPs at the forefront of industrial applications and the future of eco-friendly chemical synthesis. Full article