Search Results (44)

With increasing energy demands, fuel cells are a popular avenue for portability and low waste emissions. Hydrogen fuel cells are popular due to their potential output power and clean waste. However, due to storage and transport concerns, hydrogen peroxide fuel cells are a promising alternative. Although they have a lower output potential compared to hydrogen fuel cells, peroxide can act as both the oxidizing and reducing agent, simplifying the structure of the cell. In addition to reducing the complexity, hydrogen peroxide is stable in liquid form and can be stored in less demanding methods. This paper investigates chelated metals as electrode material for hydrogen peroxide fuel cells. Chelated metal complexes are ring-like structures that form from binding organic or inorganic compounds with metal ions. They are used in medical imaging, water treatment, and as catalysts for reactions. Copper(II) phthalocyanine, phthalocyanine green, poly(copper phthalocyanine), bis(ethylenediamine)copper(II) hydroxide, iron(III) ferrocyanine, graphene oxide decorated with Fe₃O₄, zinc phthalocyanine, magnesium phthalocyanine, manganese(II) phthalocyanine, cobalt(II) phthalocyanine are investigated as electrode materials for peroxide fuel cells. In this study, the performance of these materials is evaluated using cyclic voltammetry. The voltammograms are compared, as well as observations are made during the materials’ use to measure their effectiveness as electrode material. There has been limited research comparing the use of these chelated metals in the context of hydrogen peroxide fuel cells. Through this research, the goal is to further the viability of hydrogen peroxide fuel cells. Poly(copper phthalocyanine) and graphene oxide doped with iron oxides had strong redox catalytic activity for use in acidic peroxide single-compartment fuel cells, where the poly(copper phthalocyanine) electrode compound generated the highest peak power density of 7.92 mW/cm² and cell output potential of 0.634 V. Full article

Bupleurum scorzonerifolium Willd. is a commonly used bulk Chinese herbal remedy. Due to the large-scale mining of wild Bupleurum scorzonerifolium Willd., its natural resources are gradually exhausted. In addition, there are some problems in Bupleurum scorzonerifolium Willd. cultivation, such as lack of guidance, excessive application of fertilizers and so on, which lead to the yield and quality of Bupleurum to be below the standard value. Therefore, it is significant to clarify the regulation of quality and yield under different levels of fertilizers. In this study, three different levels of potassium fertilizer were applied; then, the metabolites in different parts of Bupleurum were analyzed by gas chromatography–mass spectrometry (GC–MS) to detect the alterations in the metabolic spectrum and recognize both the accumulation and distribution of key metabolites in response to each level of potassium fertilizer. The contents of various mineral elements, such as sodium, calcium, potassium, magnesium, manganese, zinc, iron, and copper, in different parts of Bupleurum under different potassium levels were determined. Potassium fertilizer had a significant impact on the absorption and distribution of these mineral elements. There were synergistic and antagonistic effects between each element and K⁺. The results showed that low and high potassium levels could promote the progression of main shoots and roots, but inhibited the accumulation of dry matter in lateral shoots and flowers. Low potassium levels stimulated the content of saikosaponin a in all plant parts, while high potassium levels inhibited the accumulation of most saikosaponin a,c and d. A total of 77 metabolites were identified by GC–MS, of which glycerol, d-glucose, silane and copper phthalocyanine were highlighted as the key metabolites in response to potassium fertilizer. The abovementioned metabolites are mapped into insulin signaling pathways, streptomycin biosynthesis, galactose metabolism and other metabolic pathways, sustaining the metabolic regulation of Bupleurum scorzonerifolium Willd. Full article

Developing low-cost, efficient, and scalable non-precious metal electrocatalysts for the oxygen reduction reaction (ORR) remains a critical challenge in the field of energy conversion. Among various candidates, Fe-N-doped carbon materials have garnered attention as promising alternatives to commercial Pt/C catalysts for ORR. In this study, we report an Fe-N catalyst synthesized by incorporating iron phthalocyanine with Cinnamomum longepaniculatum waste leaves as the carbon source. This catalyst exhibited an excellent four-electron ORR activity and the half-wave potential (E_1/2) reaches 0.875 V, which was superior to that of commercial Pt/C (E_1/2 = 0.864 V). Additionally, the catalyst exhibits superior methanol tolerance and stability compared to commercial Pt/C. This approach, which utilizes biomass waste for the synthesis of electrocatalysts, not only provides an effective solution for reducing environmental waste but also addresses the issue of sluggish cathodic ORR kinetics in fuel cells, making it suitable for low-cost, large-scale industrial production. Full article

In the quest for more sensitive gas sensors, researchers have studied how heating the sensors, using UV light, and thermally annealing sensors improve performance. During thermal annealing, the heating process can improve the crystallinity of the material while also increasing the electrode and sensing material interactions to create more available active sites and thus improve sensor performance. Hexadecafluorinated iron (II) phthalocyanine (FePcF₁₆) nanowires have high sensitivity towards NH₃ selectively, and thermally annealing the NWs after the deposition can further improve the sensing response and recovery. For this reason, the effect of annealing FePcF₁₆ NWs at different temperatures was studied to optimize these systems. In this work, FePcF₁₆ NWs were synthesized using physical vapor deposition (PVD) to deposit on interdigitated electrodes. The NWs were characterized by SEM, EDS, PXRD, FTIR, and Raman spectroscopy to confirm their purity. The sensors were annealed at different temperatures, inserted into a gas sensing chamber, and exposed to 1 ppm NH₃ in air, and the electrical current was measured. The results show that the optimized FePcF₁₆ NWs have excellent sensing properties, with a 58% increase in response towards NH₃ after a stepwise annealing at 300 °C confirming these systems are good prospective candidates for sensing NH₃ at room temperature. Full article

Aqueous zinc batteries are emerging technologies for energy storage, owing to their high safety, high energy, and low cost. Among them, the development of low-cost and long-cycling cathode materials is of crucial importance. Currently, Zn-ion cathodes are heavily centered on metal-based inorganic materials and carbon-based organic materials; however, the metal–organic compounds remain largely overlooked. Herein, we report the electrochemical performance of metal phthalocyanines, a large group of underexplored compounds, as alternative cathode materials for aqueous zinc batteries. We discover that the selection of transition metal plays a vital role in affecting the electrochemical properties. Among them, iron phthalocyanine exhibits the most promising performance, with a reasonable capacity (~60 mAh g⁻¹), a feasible voltage (~1.1 V), and the longest cycling (550 cycles). The optimal performance partly results from the utilization of zinc chloride “water-in-salt” electrolyte, which effectively mitigates material dissolution and enhances battery performance. Consequently, iron phthalocyanine holds promise as an inexpensive and cycle-stable cathode for aqueous zinc batteries. Full article

As a promising structure for fabricating inorganic—organic-based optoelectronic devices, metal—metallophthalocyanine (MPc) hybrid layers are highly important to be considered. The efficient charge injection and transport across the metal/MPc interface are strictly dependent on the precise molecular orientation of the MPcs. Therefore, the efficiency of MPc-based optoelectronic devices strictly depends on the adsorption and orientation of the organic MPc on the inorganic metal substrate. The current review aims to explore the effect of the terminated atoms or surface atoms as an internal stimulus on molecular adsorption and orientation. Here, we investigate the adsorption of five different phthalocyanine molecules—free-based phthalocyanine (H₂Pc), copper phthalocyanine (CuPc), iron phthalocyanine (FePc), cobalt phthalocyanine (CoPc), vanadyl phthalocyanine (VOPc)—on three metallic substrates: gold (Au), silver (Ag), and copper (Cu). This topic can guide new researchers to find out how molecular adsorbance and orientation determine the electronic structure by considering the surface–molecule interactions. Full article

A series of composites was prepared starting from five types of LDHs, which were then exchanged with three types of metallo-phthalocyanines, and, in the end, magnetic nanoparticles were attached. In the case of LDHs containing Fe, characterization data showed that there was a partial oxidation from Fe²⁺ to Fe³⁺. Samples containing evident LDH structures performed better in general than the ones containing iron oxide mixtures, the composites being more active towards amoxicillin removal compared with ampicillin removal. The nature of the phthalocyanine did not have such a great influence, although some differences in the activity were observed. The removal was a combination between adsorption and photocatalytic degradation. The best composites for this application were those based on Mg_0.325Fe_0.325Al_0.25-LDH prepared by co-precipitation in the presence of NaOH and Na₂CO₃. They presented high adsorption capacity in 10 min and, at the same time, high photocatalytic activity for both amoxicillin and ampicillin. Full article

In this paper, iron phthalocyanine nanowires on a nickel foam (FePc@NF) composite catalyst were prepared by a facile solvothermal approach. The catalyst showed good electrochemical oxygen evolution performance. In 1.0 M KOH electrolyte, 289 mV low overpotential and 49.9 mV dec⁻¹ Tafel slope were seen at a current density of 10 mA cm⁻². The excellent electrochemical performance comes from the homogeneous dispersion of phthalocyanine nanostructures on the surface of the nickel foam, which avoids the common agglomeration problem of such catalysts and provides a large number of active sites for the OER reaction, thus improving the catalytic performance of the system. Full article

Blue is one of the most challenging colors for humans to produce and one of the most important colors in art history. Literature from the Tikuna/Magüta culture, from the Amazon Forest, suggests the use of chemical reactions between the juice of the naīcü fruit and iron to produce a blue colorant still unknown among technical art historians and conservation scientists. Additionally, the coloring materials from the Tikuna/Magüta people were never chemically investigated. Therefore, this manuscript presents the investigation of blue colorants from twenty-two Tikuna/Magüta masks and one stamp used to decorate similar items. Collections from four museums, from the USA and Brazil, were examined, and Raman spectra indicated the presence of Prussian blue, phthalocyanine blue, indigo, ultramarine, crystal violet, amorphous carbon, anatase, and barium sulfate (or lithopone). Although the unknown blue colorant was not detected in this campaign, the authors hypothesize the chemical composition and reactions involved in its production by considering the chemistry of naīcü and anthocyanins. The continuation of this work with community-based participatory research (CBPR) approaches is also discussed, justifying why reproduction was not considered in this work and supporting a more socially responsible and inclusive practice in technical art history and conservation science. Full article

The organic molecules adsorbed on antiferromagnetic surfaces can produce interesting interface states, characterized by charge transfer mechanisms, hybridization of molecular-substrate orbitals, as well as magnetic couplings. Here, we apply an ab initio approach to study the adsorption of Fe phthalocyanine on stoichiometric Cr₂O₃(0001). The molecule binds via a bidentate configuration forming bonds between two opposite imide N atoms and two protruding Cr ones, making this preferred over the various possible adsorption structures. In addition to the local modifications at these sites, the electronic structure of the molecule is weakly influenced. The magnetic structure of the surface Cr atoms shows a moderate influence of molecule adsorption, not limited to the atoms in the close proximity of the molecule. Upon optical excitation at the onset, electron density moves toward the molecule, enhancing the ground state charge transfer. We investigate this movement of charge as a mechanism at the base of light-induced modifications of the magnetic structure at the interface. Full article

Microbial fuel cells (MFCs) are sustainable energy recovery systems because they use organic waste as biofuel. Using critical raw materials (CRMs), like platinum-group metals, at the cathode side threatens MFC technology’s sustainability and raises costs. By developing an efficient electrode design for MFC performance enhancement, CRM-based cathodic catalysts should be replaced with CRM-free materials. This work proposes developing and optimizing iron-based air cathodes for enhancing oxygen reduction in MFCs. By subjecting iron phthalocyanine and carbon black pearls to controlled thermal treatments, we obtained Fe-based electrocatalysts combining high surface area (628 m² g⁻¹) and catalytic activity for O₂ reduction at near-neutral pH. The electrocatalysts were integrated on carbon cloth and carbon paper to obtain gas diffusion electrodes whose architecture was optimized to maximize MFC performance. Excellent cell performance was achieved with the carbon-paper-based cathode modified with the Fe-based electrocatalysts (maximum power density-PD_max = 1028 mWm⁻²) compared to a traditional electrode design based on carbon cloth (619 mWm⁻²), indicating the optimized cathodes as promising electrodes for energy recovery in an MFC application. Full article

Conventional electrochemical sensors use voltammetric and amperometric methods with external power supply and modulation systems, which hinder the flexibility and application of the sensors. To avoid the use of an external power system and to minimize the number of electrochemical cell components, a self-powered electrochemical sensor (SPES) for hydrogen peroxide was investigated here. Iron phthalocyanine, an enzyme mimetic material, and Ni were used as a cathode catalyst and an anode material, respectively. The properties of the iron phthalocyanine catalyst modified by graphene nanoplatelets (GNPs) were investigated. Open circuit potential tests demonstrated the feasibility of this system. The GNP-modulated interface helped to solve the problems of aggregation and poor conductivity of iron phthalocyanine and allowed for the achievement of the best analytical characteristics of the self-powered H₂O₂ sensor with a low detection limit of 0.6 µM and significantly higher sensitivity of 0.198 A/(M·cm²) due to the enhanced electrochemical properties. The SPES demonstrated the best performance at pH 3.0 compared to pH 7.4 and 12.0. The sensor characteristics under the control of external variable load resistances are discussed and the cell showed the highest power density of 65.9 μW/cm² with a 20 kOhm resistor. The practical applicability of this method was verified by the determination of H₂O₂ in blood serum. Full article

Lithium–air batteries (LABs) have a theoretically high energy density. However, LABs have some issues, such as low energy efficiency, short life cycle, and high overpotential in charge–discharge cycles. To solve these issues electrocatalytic materials were developed for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which significantly affect battery performance. In this study, we aimed to synthesize electrocatalytic N-doped carbon-based composite materials with solution plasma (SP) using Co or Ni as electrodes from organic solvents containing cup-stacked carbon nanotubes (CSCNTs), iron (II) phthalocyanine (FePc), and N-nethyl-2-pyrrolidinone (NMP). The synthesized N-doped carbon-based composite materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). TEM observation and XPS measurements revealed that the synthesized carbon materials contained elemental N, Fe, and electrode-derived Co or Ni, leading to the successful synthesis of N-doped carbon-based composite materials. The electrocatalytic activity for ORR of the synthesized carbon-based composite materials was also evaluated using electrochemical measurements. The electrochemical measurements demonstrated that the electrocatalytic performance for ORR of N-doped carbon-based composite material including Fe and Co showed superiority to that of N-doped carbon-based composite material including Fe and Ni. The difference in the electrocatalytic performance for ORR is discussed regarding the difference in the specific surface area and the presence ratio of chemical bonding species. Full article

Understanding the metabolism of pharmaceutical compounds is a fundamental prerequisite for ensuring their safety and efficacy in clinical use. However, conventional methods for monitoring drug metabolism often come with the drawbacks of being time-consuming and costly. In an ongoing quest for innovative approaches, the application of electrochemistry in metabolism studies has gained prominence as a promising approach for the synthesis and analysis of drug transformation products. In this study, we investigated the hepatic metabolism of voriconazole, an antifungal medication, by utilizing human liver microsomes (HLM) assay coupled with LC-MS. Based on the obtained results, the electrochemical parameters were optimized to simulate the biotransformation reactions. Among the various electrodes tested, the chemometric analysis revealed that the iron(II) phthalocyanine electrode was the most effective in catalyzing the formation of all hepatic voriconazole metabolites. These findings exemplify the potential of phthalocyanine electrodes as an efficient and cost-effective tool for simulating the intricate metabolic processes involved in drug biotransformation, offering new possibilities in the field of pharmaceutical research. Additionally, in silico analysis showed that two detected metabolites may exhibit significantly higher acute toxicity and mutagenic potential than the parent compound. Full article

Photocatalytic coatings are difficult to obtain on textile materials because of the sometimes contradictory properties that must be achieved. In order to obtain a high efficiency of a photocatalytic effect, the metal–oxide semiconductor must be found in the vicinity of the coating–air interface in order to come into direct contact with the contaminant species and allow light radiation access to its surface. Another necessary condition is related to the properties of the covering textile material as well as to the stability of the xerogel films to light and wet treatments. In this sense, we proposed a solution based on hybrid silica films generated by sol–gel processes, coatings that contain as a photocatalyst TiO₂ sensitized with tetracarboxylic acid of iron (III) phthalocyanine (FeTCPc). The coatings were made by the pad–dry–cure process, using in the composition a bifunctional anchoring agent (3-glycidoxipropyltrimethoxysilane, GLYMO), a crosslinking agent (sodium tetraborate, BORAX), and a catalyst (N-methylimidazole, MIM) for the polymerization of epoxy groups. The photodegradation experiments performed on methylene blue (MB), utilized as a model contaminant, using LED or xenon arc as light sources, showed that the treatment with BORAX improves the resistance of the coatings to wet treatments but worsens their photocatalytic performances. Full article