Search Results (10,032)

In this work, the coordination compound sulfate of aqua{tris(2-pyridylmethyl) amine}zinc(II) ([Zn(TPA)(H₂O)]SO₄) is investigated as a catalyst for the molecular reduction of CO₂. The complex was synthesized and characterized by FT–IR, UV–Vis, TGA, and NMR spectroscopy. Cyclic voltammetry reveals irreversible electrochemical behavior, with two cathodic peaks at E_pc = −1.72 V and E_pc = −1.99 V vs. Fc/Fc⁺, respectively. Under a CO₂ atmosphere, a catalytic wave appears at E_pc = −1.87 V vs. Fc/Fc⁺, indicating catalytic activity toward CO₂ reduction. This behavior was further confirmed by Foot-of-the-Wave Analysis (FOWA), which yielded a catalytic rate constant of (k = 1.352 × 10³ M⁻¹ s⁻¹). Bulk electrolysis experiments combined with FT–IR analysis suggest that format is the main product of the CO₂ reduction catalyzed by [Zn(TPA)(H₂O)]SO₄. Electrochemical impedance spectroscopy was used to examine the catalytic process at the electrode–electrolyte interface. In addition, density functional theory (DFT) calculations were conducted to analyze the interaction between the [Zn(TPA)(H₂O)]SO₄ complex and CO₂. Full article

3-Acetyl-1-propanol (3-AP) is a key intermediate in the pharmaceutical and pesticide industries, which can be synthesized from the biomass derivative 2-methylfuran (2-MF) through a one-step hydrogenation process with significant economic and environmental benefits. Zeolite-supported metal catalysts showed feasible application, but simply regulating the acidic sites was difficult to break the activity–selectivity balance. Traditional single-metal Pd-based catalysts still suffer from low dispersion. This study constructed the PdZn/TS-1 catalyst for the efficient conversion of 2-MF into 3-AP. The low electronegativity of Zn facilitates the electron transfer from Zn to Pd, forming an electron-rich Pd active center. A small amount of Zn embedded in the Pd lattice causes lattice contraction, optimizing the spatial configuration of active sites. The synergy between the electronic and structural effects significantly improves catalytic performance. Under optimized conditions, the conversion rate of 2-MF reached 80.6%, and the yield of 3-AP reached 69.1%, providing a new paradigm for the design of catalysts for the directed hydrogenation of furan derivatives. Full article

Grape marcs represent one of the most effectively exploited biowaste resources through cascade valorization approaches, in which byproducts are processed via multiple sequential steps such as extraction, bio-treatment, and pyrolysis. In this study, we present a novel route for producing graphitic carbon (GC) from grape seeds derived from exhausted marc via pyrolysis. We integrate hydropyrolysis and CO₂ methanation in a one-pot methodology to valorize both bio-oil and gaseous pyrolysis byproducts. The GC obtained through pyrolysis is evaluated in GC/Polytetrafluoroethylene (PTFE) composites as an electromagnetic interference (EMI) shielding material across the X-band frequency range (8–12 GHz). This work demonstrates a viable and eco-friendly pathway to upcycle abundant biomass into a lightweight, sustainable, and highly tunable material, which represents a promising candidate for effective EMI shielding while simultaneously mitigating process emissions. Full article

Reforming processes are key technologies for the production of hydrogen and synthesis gas from hydrocarbon feedstocks, with steam reforming and dry reforming being the most extensively studied routes. Steam reforming remains the dominant industrial process due to its high efficiency and economic viability; however, its associated CO₂ emissions raise environmental concerns, partially mitigated through an integration with carbon capture and storage technologies. Dry reforming has emerged as an attractive alternative, although it requires high operating temperatures and suffers from catalyst deactivation. Catalyst design is therefore critical for improving process efficiency and stability. Supported metal catalysts, particularly Ni-based systems, are widely employed, with the support material playing a decisive role in metal dispersion, resistance to sintering and coking, and reaction selectivity. Microporous and mesoporous silica-based materials, including zeolites and ordered mesoporous silicas, offer tunable structural and surface properties that enhance catalytic performance. The novelty of this work lies in its holistic approach to reforming catalysis, where the catalytic performance is not discussed solely in terms of active metals, but is systematically correlated with the surface properties, chemical composition, and structural features of silica-based supports. Moreover, this study expands the perspective to alternative and less-explored feedstocks. By considering multiple fuels and support types, the study provides new design guidelines for developing more efficient and sustainable reforming catalysts. Full article

The reaction of CO₂ hydrogenation into CH₄ provides an industrial-scale pathway for CO₂ recycling. The controllable design of catalysts with highly active and stable performance is challenging, and investigation of the reaction mechanism is of great significance. In this paper, the reasonable regulation scheme on designing excellent performance catalysts is proposed, and all the reaction paths on the surface of catalysts are also analyzed in detail. It emphasized the fundamental factors influencing the activity of catalysts, and it proposed some practical strategies to effectively improve the performance of the catalysts in combination with the structure–activity relationship. This work has great significance for the optimal performance catalysts of heterogeneous catalytic systems. Furthermore, it provided a rationalized approach to designing catalysts with specific nanostructures and surface properties, such as catalytic reforming, dehydrogenation, hydrogenation, electric catalysis, and many other reactions. In addition, a critical perspective on the future challenges and opportunities in designing high performance catalysts is provided. Full article

Effective electrochemical CO₂ reduction to liquid fuels requires that the local catalytic environment facilitates the desired reactivity, yet a microscopic understanding of this environment is difficult to achieve from experiment alone. In this work, a 3D reaction-diffusion model was developed to explore the effects of electrode surface area and local geometry on the performance of a heterogeneous catalyst that performs a two-step CO₂ reduction cascade reaction to CO and then CH₃OH under aqueous conditions. Kinetic parameters for the model were inspired by experimental results using a cobalt phthalocyanine (CoPc) catalyst. Three-dimensional architectures composed of arrays of square pillars with varying dimensions and either smooth or periodically modulated surfaces were tested, revealing the extent to which geometry modulates the performance of the cascade reactions. Although structural variations modulate local concentration gradients, we find that electrochemically active surface area predominantly governs the overall cascade reaction. Moreover, the results suggest that supersaturation of CO, with concentrations up to ten-fold higher than the equilibrium solubility limit, might be critical for more efficient conversion to CH₃OH. For any given geometry, the spatially averaged ratio of [CO] to [CO₂] is dictated by the electrochemically active surface area and determines the yield of CH₃OH. For a fixed surface area, geometries that spatially confine the electrolyte yield moderate local [CO] to [CO₂] ratios within small volumes. In contrast, less confining geometries result in a broader distribution of local ratios spread over larger volumes, with both configurations yielding the same spatially averaged [CO] to [CO₂] ratio. These insights provide valuable design principles—highlighting the critical importance of surface area and possibly CO supersaturation—for engineering advanced electrode architectures that leverage intermediate trapping and CO supersaturation to enhance overall performance in tandem CO₂ reduction systems. Full article

One-dimensional alumina nanorods have garnered significant attention due to their unique physical and chemical properties, which hold great promise for applications in catalysis, sensing, and other fields. However, the precise control over the morphology and properties of these nanorods remains a challenge, particularly in achieving a high specific surface area and desirable crystallinity. In this work, we explored the hydrothermal synthesis of alumina nanorods, focusing on the effects of structure-directing agents. It was observed that extending the hydrothermal time and optimizing the temperature led to the formation of nanorods with enhanced crystallinity and specific surface area. The addition of urea and different structure-directing agents significantly influenced the morphology and properties of the nanorods. Furthermore, density functional theory (DFT) calculations revealed the underlying mechanisms of how these structure-directing agents affect the adsorption and growth of alumina nanorods on different crystal planes. Our findings suggest that by carefully tuning these parameters, it is possible to achieve alumina nanorods with optimized properties. This work not only provides a systematic approach to the synthesis of alumina nanorods but also opens up new possibilities for the development of advanced materials with tailored properties for a wide range of applications. Full article

This review presents the covalent chemistry of carbon from the point of the spin-radical concept of electron interaction in the framework of the unrestricted molecular orbitals (UHF MO) theory. Using the language of valence bond trimodality, the regions of classical spinless spin-symmetric covalence and its spin-dependent asymmetric counterpart are defined. Carbon is the only element exhibiting spin covalent chemistry. Classical covalent chemistry of carbon of molecular substances whose valence bond structure includes segregate or chained single sp³C − C bonds meet its spin counterpart only at these bonds breaking. Substances with double sp²C = C and triple sp¹C ≡ C bonds are the subject of spin covalent chemistry of carbon. The mathematical apparatus of the UHF MO allows forming algorithms controlling the chemical modification of carbon substances, polymerization processes, and catalysis involving them, making it possible to supplement the empirical spin covalent chemistry of carbon with its virtual analog. Full article

Copper(II) oxide (CuO) nanoparticles are of growing interest due to their versatility in catalysis, energy storage, and environmental remediation. In this work, a novel air-assisted polyol–thermal decomposition method was developed to synthesize crystalline CuO nanoparticles with a controlled size. The reaction used copper(II) acetate in 1,4-butanediol at 140 °C under varying airflow conditions and reaction times, followed by calcination at 400 °C in air. Continuous air bubbling minimized the formation of Cu₂O and metallic Cu, while maximizing the CuO yield with shortened reaction times. The optimal conditions involved a 4 h polyol reaction while purging air at 1800 cm³/min, followed by 4 h of calcination. This method resulted in polycrystalline monoclinic CuO nanoparticles with a size of 73 ± 32 nm, as observed by TEM and XRD. FT-IR and Raman spectroscopy verified the compositional purity of the nanoparticles. To enhance colloidal stability, a citrate coating reaction of CuO was optimized using sodium citrate dihydrate or citric acid in either water or 1,4-butanediol. The optimal coating conditions employed sodium citrate in water with bath sonication and overhead stirring, yielding a zeta potential of −40.6 ± 0.4 mV at pH 7. This work provides a practical and tunable method for producing high-quality CuO nanoparticles suitable for diverse applications. Full article

Linalyl acetate is a key bioactive component of essential oils with notable calming and sedative effects; however, its high volatility severely limits stability and practical application. Herein, bimodal mesoporous silica (BMMs) was employed as an efficient carrier to encapsulate linalyl acetate using liquid- and gas-phase loading strategies, enabling high loading capacity and sustained release. Under optimized gas-phase conditions (600 mg·mL⁻¹, 85 °C, 2 h), a maximum loading capacity of 80.13% was achieved. The X-ray diffraction (XRD) and small-angle X-ray scattering (SAXS) patterns, scanning electron microscopy (SEM) images, N₂ adsorption–desorption isotherms, Fourier transform infrared (FT-IR) spectra, and thermogravimetric (TG) performances confirmed the successful confinement of linalyl acetate within the bimodal mesoporous channels. Particularly, the SAXS patterns revealed the pronounced fractal characteristics, whereas the increased mass-fractal dimension (D_m) values indicated the enhanced structural compactness, and higher surface-fractal dimension (D_s) values reflected increased surface roughness upon loading. Release experiments conducted in an open environment demonstrated an excellent sustained-release performance, with only 22.41% of linalyl acetate released from BMMs over 30 days, compared with 94.41% for the free compound. Molecular dynamics simulations further elucidated that the interactions between linalyl acetate molecules and surface silanol groups dominated the adsorption process and governed diffusion within the mesoporous channels. These findings suggested that BMMs provide a robust platform for stabilizing volatile fragrance compounds and achieving long-term controlled release. Full article

It is of great significance to prepare carbon-supported non-noble metal catalysts for hydrogen evolution reaction (HER) via a sustainable method. Meanwhile, the enhanced metal-support interaction (MSI) is vital for promoting the catalytic activity of metal/carbon catalysts. Herein, we prepare a biomass-derived porous carbon-supported metal Ni catalyst (Ni/APC) with the enhanced MSI via atomic Ni-N₄ sites utilizing agaric as a precursor. The highly dispersed Ni-N₄ species preferentially adsorb dye molecules and reactant H₂O, beneficial to efficient electron transfer and promoting H₂O dissociation. Meanwhile, Ni nanoparticles undertake the active sites for H₂ desorption. In virtue of the synergistic effect of metal Ni nanoparticles and atomic Ni-N₄ for different roles of active sites, Ni/APC catalysts show more effective dye-sensitized photocatalytic HER activities, compared with pure Ni and pure APC. The Ni/APC catalyst with an optimal Ni loading amount exhibits a high AQY of 41.0% with an excellent long-term stability in terms of both HER activity and structure. It is the first report of an application for biomass-derived carbon catalysts in dye-sensitization hydrogen production, and the synergistic effect of atomic Ni and particled Ni on the dye-sensitized photocatalytic HER is deeply investigated. This work provides new deep insight into the design of new non-noble metal/carbon materials by taking advantage of biomass materials. Full article

A green and efficient method was developed for the synthesis of 1,8-dioxo-octahydroxanthene derivatives using linear alkylbenzene sulfonic acid (LABSA) as an eco-friendly Brønsted acid catalyst under aqueous reflux conditions. This system combines micellar catalysis and acid activation to afford tricyclic products in high yields and with excellent purity. The transformation proceeds via a Knoevenagel–Michael sequence between dimedone and aromatic aldehydes, followed by intramolecular cyclization. The method exhibits broad substrate tolerance, affording yields between 80 and 92. The simplicity, scalability, and environmental compatibility of this process establish LABSA as a promising alternative to conventional acids for the green synthesis of pharmacologically relevant xanthene derivatives. Full article

The sluggish reduction kinetics of thionyl chloride and the cathode passivation induced by the densification deposition of discharge product LiCl are critical challenges that severely hinder the commercialization of lithium/thionyl chloride (Li/SOCl₂) batteries. In this work, a dual-catalyst cobalt tetrapyridine porphyrin (CoTAP) and copper phthalocyanine (CuPc) supported on activated carbon (AC) were proposed to synergically regulate SOCl₂ reduction and product deposition. When the CoTAP/CuPc/AC catalyst was synthesized and applied as the cathode of Li/SOCl₂ batteries, UV-Vis spectroscopy, crystal field coordination structure analysis, DFT calculations and XPS measurements collectively demonstrated that CoTAP catalyzes SOCl₂ reduction through coordination at Co sites and strongly adsorbs Cl⁻, while CuPc features a weakly coordinated Cu center that facilitates the migration of LiCl products from the cathode surface. This collaborative effect in CoTAP/CuPc/AC cathodes effectively accelerates the reduction kinetics of SOCl₂ and promotes the ordered deposition of product LiCl, thereby guaranteeing the continuous and progressive discharge process in Li/SOCl₂ batteries. As a result, the CoTAP/CuPc/AC-catalyzed batteries exhibited excellent electrochemical performance with a stable discharge voltage of 3.16 V and high discharge capacity of 15.08 mAh, superior to the counterpart batteries without catalysts. This work provides a design idea for the development of advanced Li/SOCl₂ batteries. Full article

Mining tailings are considered a significant environmental challenge due to their large quantities and high residual metal content, particularly iron. Recent developments in biogenic technologies offer a sustainable approach to recovering valuable materials from these waste streams. We consider a biogenic iron oxide nanoparticles production process from mining tailings as an environmentally friendly route to magnetic materials. Microorganisms, including iron-oxidizing and iron-reducing bacteria, microalgae, and fungi, can convert soluble and mineral-bound iron into iron oxide nanoparticles (NPs) phases such as magnetite, maghemite, and hematite. These biogenic iron oxide NPs often exhibit specific physicochemical properties, including controlled particle size, high surface area, and engineered magnetic properties, which make them potentially important for applications in environmental remediation, catalysis, and agriculture. The processes behind microbial iron conversion, the parameters governing mineral phase formation, and the approaches for optimizing the process are presented. This strategy supports the circular economy concept by combining biogenic synthesis with various forms of mining waste, thereby reducing environmental threats associated with tailings confinement and providing an environmentally friendly mechanism for the production of value-added magnetic materials. Full article