Sole Catalyst Research Articles

The Central Functions of Cities in Poland in Light of Administrative Reform

The aim of this article is to determine and assess the changes in the central functions of major Polish cities in the context of Poland’s 1999 administrative reform. This study covers a period of twenty-two years (1998–2019), which provides a solid perspective for evaluating the functional changes occurring within the current territorial division of the country. The conclusions indicate that the dynamics of changes in central functions in former provincial capitals differed from those in cities that retained this status. At the same time, it was found that the administrative reform sanctioned the scope and scale of earlier socio-economic dependencies in the present regional centers. The research results suggest that administrative reforms in Poland solidified existing socio-economic development paths in cities, but were not the sole catalyst for change. They point to a complex interaction of factors influencing urban evolution. By utilizing indicators that measure the centrality of cities in relation to their demographic potential, this research offers a quantitative assessment of the level of development of central functions, which is crucial for monitoring progress towards sustainable urbanization. By providing this information, this research also contributes to a broader discussion on the advancement and dynamics of sustainable urban development.

Pt/facet-Engineered Hydroxyapatite Co-Catalyst for Highly Efficient Hydrolysis of Ammonia Borane

Ammonia borane (AB, NH3BH3) is a promising candidate for a hydrogen-storage material because of its high stability as a solid state at room temperature under atmospheric pressure. This study demonstrated a novel catalyst design for highly efficient hydrolysis of AB by hybridizing Pt catalyst with hydroxyapatite (HAp, Ca10(PO4)6(OH)2) as an “active support”, possessing Lewis-acidic Ca2+ sites in the a-plane and Lewis-basic PO43- sites in the c-plane. Facet-engineered HAp particles were synthesized via the microwave-assisted hydrothermal reaction using Ca-EDTA chelates. Varying the Ca/P ratio of HAp precursor (from 1.5 to 1.8) affected the particle morphology, exposed facet ratio of {300} to {002}, and the percentage of phosphate anion species (PO43- and HPO42-). The rod-like HAp sole catalysts performed approximately 2-fold higher activity for the hydrolysis of AB, compared with spherical HAp with low crystallinity. Moreover, the Pt/rod-like HAp co-catalyst demonstrated superior catalytic performance with a turnover frequency (TOF) of 623 molH2 molPt-1 min-1 than the Pt/spherical HAp (<232 molH2 molPt-1 min-1). We proposed a possible mechanism of a synergistic effect in the significant enhancement of the hydrogen release rate from AB. Lewis basic PO43- and Lewis acidic Ca2+ sites on HAp would affect preferential adsorption of electron-deficient BH3 and electron-rich NH3 groups in AB, catalyzing cleavage of B-N bonds. Besides, PO43- sites play a critical role in anchoring Pt particles towards electron transfer from Pt to PO43-, resulting in considerable enhancement of catalytic performance in dissociative adsorption of water molecules, which is a rate-determining step in the hydrolysis.Graphical

Copper-Catalyzed [4+1+1] Annulation of Ammonium Salts and Anthranils: Synthesis of 2,3-Diaroylquinolines.

A copper(I)-catalyzed protocol is developed for the synthesis of various 2,3-diaroylquinolines starting from achiral ammonium salts and anthranils through [4+1+1] annulation. Using copper(I) chloride as the sole catalyst, this reaction is featured with easily available starting materials, broad substrate scope, good yields and simple reaction conditions.

Single-Atomic Co-N4 Sites with CrCo Nanoparticles for Metal-Air Battery-Driven Hydrogen Evolution.

Designing highly active and robust earth abundant trifunctional electrocatalysts for energy storage and conversion applications remain an enormous challenge. Herein, we report a trifunctional electrocatalyst (CrCo/CoN4@CNT-5), synthesized at low calcination temperature (550 °C), which consists of Co-N4 single atom and CrCo alloy nanoparticles and exhibits outstanding electrocatalytic performance for the hydrogen evolution reaction, oxygen evolution reaction, and oxygen reduction reaction. The catalyst is able to deliver a current density of 10 mA cm-2 in an alkaline electrolytic cell at a very low cell voltage of ∼1.60 V. When the catalyst is equipped in a liquid rechargeable Zn-air battery, it endowed a high open-circuit voltage with excellent cycling durability and outperformed the commercial Pt/C+IrO2 catalytic system. Furthermore, the Zn-air battery powered self-driven water splitting system is displayed using CrCo/CoN4@CNT-5 as sole trifunctional catalyst, delivering a high H2 evolution rate of 168 μmol h-1. Theoretical calculations reveal synergistic interaction between Co-N4 active sites and CrCo nanoparticles, favoring the Gibbs free energy for H2 evolution. The presence of Cr not only enhances the H2O adsorption and dissociation but also tunes the electronic property of CrCo nanoparticles to provide optimized hydrogen binding capacity to Co-N4 sites, thus giving rise to accelerated H2 evolution kinetics. This work highlights the importance of the presence of small quantity of Cr in enhancing the electrocatalytic activity as well as robustness of single-atom catalyst and suggests the design of the multifunctional robust electrocatalysts for long-term H2 evolution application.

Microwave-Accelerated Synthesis of Flavanones through Oxidative Cyclization of 2'-Hydroxychalcones Using Acetic Acid as a Sole Catalyst

Under microwave irradiation conditions, 2'-hydroxy chalcones 1a-c underwent AcOH-mediated cyclization in an oxa-Michael addition manner to afford flavanones 2a-c in acceptable yields (up to 82%). These reactions proceeded in a shorter reaction time (~ 30 min) through microwave activation; otherwise, the reaction would take several days and even weeks, if a conventional heating process was employed. For example, cyclization of (E)-1-(2-hydroxyphenyl)-3-phenylprop-2-en-1-one (1a) has required 4 days of stirring with AcOH (0.25 M), under conventional heating at 100 °C, to produce 2-phenylchroman-4-one (2a), in 75% yield; while under microwave conditions, the reaction has yielded 82% of compound 2a, after 30 min. Thus obtained products 2a-c were fully characterized by recording of melting point together with UV, 1H NMR, and 13C NMR spectra.

Asymmetric Synthesis of Planar Chiral Carbonitriles and Amines via Carbene-Catalyzed Kinetic Resolution.

We have developed a catalytic method using chiral N-heterocyclic carbene (NHC) as the sole organic catalyst to synthesize planar chiral carbonitriles asymmetrically, resulting in optically pure, multifunctional compounds. The method demonstrates remarkable tolerance toward diverse substituents and substitution patterns through kinetic resolution (KR) or desymmetrization processes. The resulting optically pure planar chiral products hold significant potential for applications in asymmetric synthesis and antibacterial pesticide development.

Aryl Ketone‐Catalyzed Light‐Driven Radical Oxy‐Functionalization of Non‐Acidic C(sp3)−H Bonds Enabled by Triple Role of TEMPO

AbstractA light‐driven radical oxy‐functionalization of non‐acidic aliphatic and benzylic C(sp3)−H bonds was achieved with 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) in a single‐step by employing an aryl ketone as a sole catalyst. The transformation was initiated by homolysis of a C(sp3)−H bond in the starting substance by the photo‐excited aryl ketone. The derived carbon radical was then promptly trapped by TEMPO leading to the formation of the TEMPO‐adduct. The derived TEMPO‐adduct is synthetically versatile as an alcohol equivalent since it can be readily converted to the corresponding ketone by oxidation and to the corresponding alcohol by reduction. The key to realizing the present catalytic reaction relies on the distinctive triple role of TEMPO, which acts as the precursor of the oxygen functionality, the oxidant to regenerate the aryl ketone, and the protective group for the derived TEMPO‐adduct from over‐oxidation.

Commonwealth of Independent States Transformation: Moving from Stagnation to Semi-Periphery

This study examines the post-Soviet states, emphasizing the divergent developments in the Baltic states and the Commonwealth of Independent States (CIS), with a specific focus on Uzbekistan. It highlights the central role of regional cooperation and integration as key drivers of economic growth. The success of the Baltic states is attributed to strong regional cooperation, consistent economic policies, and cultural similarities, while CIS members struggle with challenges related to political instability and security risks. The study challenges the conventional assumption that full market liberalization is the sole catalyst for economic growth and emphasizes the significance of active state involvement in promoting regional integration. The findings suggest the need for a nuanced approach to managing political instability, promoting regional cooperation, and balancing market liberalization and state control to enhance economic performance. Recent developments in Uzbekistan, including the eradication of black markets, bolstering regional connections, and attracting more foreign investment, indicate the potential for substantial economic growth.

Calcium sulfates in planetary surface environments

Calcium sulfates play a key role in both industrial processes and the global sulfur cycle. In arid to hyper-arid planetary surface environments, they can be used to assess the availability of water to the environment. Yet, the processes through which calcium sulfate minerals (i.e. gypsum, bassanite, anhydrite) and the anhydrous γ-CaSO4 form and transform remain insufficiently understood. Especially the dissolution-reprecipitation reaction from gypsum to anhydrite has to this date been achieved in the laboratory only under very specific conditions.Recent evidence suggests the importance of solution flow as opposed to batch reactions in aiding the precipitation of anhydrite at room temperature. Our own results, however, clearly show, that solution flow alone cannot be the sole catalyst. In light of the recent abundance of research towards the nucleation and crystallization of calcium sulfates, we present this review in an attempt to summarize and contextualize these new results and to identify necessary directions for further research with focus on conditions of arid and hyper-arid planetary environments.

Tandem Conversion of Fructose to Bio‐diketones Using a Multifunctional Pd‐POPs‐CF3SO3H Catalyst

AbstractTandem conversion of biomass to value‐added fine chemicals is a significant challenge. For instance, the production of fine chemicals from fructose involves conversion to 5‐hydroxymethylfurfural (5‐HMF), followed by another reaction and purification. Dual catalyst systems have been used in nearly every study on the tandem conversion of fructose to bio‐diketones. Therefore, a sole multifunctional heterogeneous catalyst was developed in this study for the tandem conversion of fructose to bio‐diketones, which has not been reported previously. Instrument corrosion and the separation or purification of 5‐HMF were avoided using the multifunctional heterogeneous catalyst, which contained integrated active sites of acid, metal, and anions. The multifunctional CF3SO3H‐functionalized porous‐organic‐polymers(POPs)‐supported Pd catalyst (Pd‐POPs‐CF3SO3H) was prepared using a series of modifications. A bio‐diketone yield of 51.0 % was achieved using Pd‐POPs‐CF3SO3H in the tandem conversion of fructose with an excellent TOF of 88.3 h−1 which is much more efficient than catalyst reported in literatures. Pd‐POPs‐CF3SO3H could be reused at least three times with stable performance. Control experiments and characterization results proved that the high specific surface area, hierarchical pore structure, abundance of CF3SO3−1 anions, and proximity of Pd moieties and acid sites (“The closer the better” principle) led to the decent performance for bio‐diketone.

Immobilization of Ag nanoparticles on NiFe2O4@TiO2@PDA: Multifunctional catalytic action toward the reduction of 4-Nitrophenol and photodegradation of methylene blue and ciprofloxacin

Freshwater, an essential commodity of life, is under threat by the presence of pernicious chemicals, such as 4-nitrophenol (4-NP), organic azo dyes, and colorless antibiotic pollutants, leading to water pollution. It is an absolute necessity to transform these pernicious chemicals into benign compounds to mitigate water pollution and safeguard life on Earth. One such effort in the current work is the development of a recyclable, multifunctional, and heterogeneous NiFe2O4@TiO2@PDA-Ag magnetic nanocatalyst for the reduction of 4-NP to 4-aminophenol (4-AP) and the photocatalytic degradation of methylene blue (MB) (an organic azo dye) and ciprofloxacin (CIP) (a colorless antibiotic pollutant) under irradiation with direct sunlight. Characterization of the developed catalyst was achieved using various spectroscopic and analytical methods (XRD, FTIR & UV–Vis spectroscopy, SEM, TEM, and XPS). The visible light active nature of the catalyst was confirmed by our UV–Vis spectroscopic data. The reduction of 4-NP to 4-AP with 97% conversion was achieved using the catalyst at room temperature in an aqueous medium in the presence of sodium borohydride (NaBH4) at a rate constant of 0.462 min−1. The photocatalytic degradation of MB and CIP was achieved using the catalyst under irradiation with direct sunlight, in which 96.5 and 68% degradation was observed with a degradation rate constant of 0.0483 and 0.0750 min−1 respectively. The presence of a magnetic NiFe2O4 core in the catalyst enables its recovery with the aid of the external magnet, its reusability was assessed and exhibited good efficacy up to five cycles. The magnetic nature of the catalyst was confirmed using vibrating sample magnetometry (VSM). The synthesis of a sole reusable magnetic catalyst suitable for the removal of three toxic pollutants under normal conditions adopting a facile methodology with excellent activity up to five cycles is rare and thus, the findings from the present work provide helpful information in wastewater treatment.

Chiral Self-Assembly Behavior of Carboxylated Cellulose Nanocrystals Isolated by Recyclable Oxalic Acid from Degreasing Cotton

Carboxylated cellulose nanocrystals (OA-CNCs) isolated by aqueous recyclable oxalic acid hydrolysis from degreasing cotton were used to observe its self-assembly behavior and chiral nematic properties. The oxalic acid here served as the sole catalyst to esterify and hydrolyze the degreasing cotton. The results indicated that the obtained OA-CNC suspensions were spontaneously phase-separated into a chiral nematic mesophase above a critical concentration, and the occurrence of chiral self-assembly is highly dependent on the aspect ratio and the surface charge of the OA-CNC suspension. Scanning electron microscopy images of the cross section of OA-CNC solid films revealed a periodic ordered multilayer structure. The residual OA was easily recovered through simple re-crystallization method after reactions with a high recovery rate of at least 90%. The recycled OA (ROA) had excellent performance in terms of ROA-CNC yield even after reusing for five cycles. Moreover, the resultant ROA-CNCs from recycled OA could also form chiral nematic ordered phases with little change in the critical concentration and pitch, suggesting excellent suitability for sustainable OA-CNC production for photonics and other specialty applications.

Revealing and Regulating the Complex Reaction Mechanism of CO2 Hydrogenation to Higher Alcohols on Multifunctional Tandem Catalysts

Revealing and regulating the intricate reaction mechanism of direct CO2 hydrogenation to higher alcohols (C2+OH), especially for the crucial C–C coupling step, is still a great challenge. Herein, the specific reaction network on Co2C and CuZnAl multifunctional tandem catalysts is elucidated by designing subtly surface adsorption–desorption reactions, in situ chemical transient kinetics, and theory calculations. The key C–C coupling step for the formation of C2+OH over the sole Co2C catalyst was the insertion of CO into R-CHx, while the reaction mechanism can be modulated to the coupling of R-CH2 and CHO with a lower energy barrier on the tandem catalyst (Co2C||CuZnAl). R-CH2 was derived from the hydrogenation dissociation of olefins and coupled with the CHO from formate hydrogenation at the Cu/ZnAl2O4 interface. Such multifunctional tandem catalysts exhibited a high space–time yield of C2+OH of 2.2 mmol g–1 h–1. This work provides an effective strategy for studying complex mechanisms, contributing to the precise design of highly efficient catalysts and the optimization of reaction pathways.

Hemp Protein Hydrolysates Modulate Inflammasome-Related Genes in Microglial Cells.

A prolonged inflammatory response can lead to the development of neurodegenerative diseases such as Alzheimer's disease. Enzymatic hydrolysis is a sustainable way to increase the value of protein sources by obtaining peptides that can exert bioactivity. Hemp (Cannabis sativa L.) protein hydrolysates have been proven to exert anti-inflammatory activity. In this study, two hemp protein hydrolysate (HPHs), obtained with Alcalase as sole catalyst, or with Alcalase followed by Flavourzyme, were evaluated as inflammatory mediators (TNFα, IL-1β, IL-6, and IL-10), microglial polarization markers (Ccr7, iNos, Arg1, and Ym1), and genes related to inflammasome activation (Nlrp3, Asc, Casp1, and Il18), employing the lipopolysaccharide (LPS)-induced neuroinflammation model in murine BV-2 microglial cells. A significant decrease of the expression of proinflammatory genes (e.g., Tnfα, Ccr7, inos, and Nlrp3, among others) and increase of the expression anti-inflammatory cytokines in microglial cells was observed after treatment with the test HPHs. This result in the cell model suggests a polarization toward an anti-inflammatory M2 phenotype. Our results show that the evaluated HPHs show potential neuroprotective activity in microglial cells via the inflammasome.

Microwave-Assisted Domino Povarov-Type [4+2] Cycloaddition: A Rapid Access to 7-Phenyl-6H-chromeno[4,3-b]quinolines

AbstractA convenient, facile, and eco-friendly approach to synthesizing 7-phenyl-6H-chromeno[4,3-b]quinolines under microwave irradiation is presented. The current strategy enabled the synthesis of chromenoquinoline frameworks at 80 °C under shorter reaction times via intermolecular Schiff base formation followed by an intramolecular inverse demand hetero-Diels–Alder [4+2]-cycloaddition reaction by using a catalytic amount of copper triflate as the sole catalyst. Consequently, one C–N and two C–C bonds are constructed in a single pot, and a wide spread of 7-phenyl-6H-chromeno[4,3-b]quinolines have been synthesized with good functional group tolerance.

Highly Selective Electrochemical Synthesis of Urea Derivatives Initiated from Oxygen Reduction in Ionic Liquids.

The development of more efficient and sustainable methods for synthesizing substituted urea compounds and directly utilizing CO2 has long been a major focus of synthetic organic chemistry as these compounds serve critical environmental and industrial roles. Herein, we report a green approach to forming the urea compounds directly from CO2 gas and primary amines, triggered by oxygen electroreduction in ionic liquids (ILs). These reactions were carried out under mild conditions, at very low potentials, and achieved high conversion rates. The fact that O2 gas was utilized as the sole catalyst in this electrochemical loop, without additional reagents, is a significant milestone for eco-friendly syntheses of C-N compounds and establishes an effective and green CO2 scavenging method.

Activation of persulfate using copper oxide nanoparticles for the degradation of Rhodamine B containing effluents: Degradation efficiency and ecotoxicological studies

The development and implementation of advanced oxidation processes (AOP) are intended to assist in the treatment of effluents produced during anthropogenic activities, reducing the release of chemicals to the environment and consequently their potential toxicity to the environment. The present work is intended to assess the chemical and ecotoxicological efficiency of an AOP that uses copper oxide nanoparticles (CuO-NP) and persulfate (PS, as an oxidation agent) for the removal of Rhodamine B (RhB) from an aqueous solution. For this, CuO-NPs were prepared and used as a sole catalyst or combined with thermal treatment to activate PS for the degradation of RhB (in distilled water, DI, and in ASTM medium). Kinetic and mechanistic studies were employed to understand the performance of the system. The lethal ecotoxicity of the untreated and treated RhB solution was characterized using rotifer species Brachionus calyciflorus. Complete removal of RhB was achieved at [RhB]0 = 50 mg/L, [PS]0 = 1 mM, CuO = 0.5 g/L under pH = 7.5 at 45 °C for DI and ASTM. Brachionus calyciflorus mortality pointed to a very high ecotoxicity of the effluent before and after the AOP treatment; the former was less toxic than the latter: LC50,24h = 44.3% and 8.24%, respectively. Mortality observed in the treated effluent was most probably due to the presence of reaction products (e.g., activated PS) rather than RhB, since CuO/PS system was able to remove >90% of RhB. The obtained results demonstrated that although the proposed method is applicable to deal with high concentrations of recalcitrant organic compounds, the treated effluents can cause high ecotoxicity when released into the environment.

FeCo nanoalloys encapsulated in N-doped carbon nanofibers as a trifunctional catalyst for rechargeable Zn-air batteries and overall water electrolysis

Developing low-cost, high-efficiency and durable trifunctional electrocatalysts for enhancing the speed of oxygen reduction, oxygen evolution and hydrogen evolution reactions (ORR, OER and HER) is critical for expanding the industrial production and the commercial application of rechargeable Zn-air batteries and water electrolysis, but it still exists as a tremendous challenge. Herein, FeCo nanoalloys embedded into N-doped carbon nanofibers was prepared as a superior trifunctional catalyst for ORR, OER and HER by a universal and facile method. Under the synergistic effect of FeCo nanoalloys and N-doped carbon nanofibers, the Fe, Co/N-C catalyst exhibits half-wave potential of 0.86 V for ORR, and overpotentials of 388 mV and 249 mV at 10 mA·cm−2 for OER and HER, respectively. What’s more, the Zn-air battery based on Fe, Co/N-C catalyst displayed a considerable open-circuit voltage of 1.5 V and a continuous cycle life span of 210 h. Moreover, this catalyst was also used as the sole catalyst in overall water splitting to show excellent performance. This work provides an effective way to design efficient and durable multifunctional electrocatalysts, which will facilitate the development of high-performance multifunctional catalysts and their application in renewable energy applications.

Mechanistic Insights into Graphene Oxide Driven Photocatalysis as Co-Catalyst and Sole Catalyst in Degradation of Organic Dye Pollutants

Photocatalysis is a promising route to utilize sunlight, which has been potentially used to solve energy as well as environmental problems with an emphasis on fundamental understanding and technological applications in society. Semiconductors are excellent photocatalysts but often show less efficient activities due to the fast recombination of photogenerated charge carriers and very slow kinetics of surface photochemical reactions. However, recent advancements show promising strategies to improve their photocatalytic activities, including surface modifications using suitable co-catalysts and the development of novel efficient photocatalysts. Graphene oxide (GO) is one of such nanomaterials which shows multifarious roles in photocatalysis with a great potential to act as an independent solar-driven sole photocatalyst. In this minireview, the photochemistry of GO has been discussed in view of its multifarious roles/mechanisms in improving the photocatalytic activity of metal oxide semiconductors, plasmonic nanomaterials, and also their nanocomposites. In addition, recent advancements and applications of such GO-based photocatalysts in photocatalytic degradation of organic dye pollutants, including engineering of GO as the sole photocatalyst, have been discussed. Furthermore, the challenges and future prospects for the development of GO-based photocatalysts are discussed.

Reclaiming the Value of Cotton Waste Textiles: A New Improved Method to Recycle Cotton Waste Textiles via Acid Hydrolysis

The fashion industry is becoming one of the largest emitters worldwide due to its high consumption of raw materials, its effluents, and the fact that every garment will eventually contribute to the vast amount of waste being incinerated or accumulating in landfills. Although fiber-to-fiber recycling processes are being developed, the mechanical properties of the textile fibers are typically degraded with each such recycle. Thus, tertiary recycling alternatives where textiles are depolymerized to convert them into valuable products are needed to provide end-of-life alternatives and to achieve circularity in the fashion industry. We have developed a method whereby cotton waste textiles are depolymerized to form a glucose solution, using sulfuric acid as the sole catalyst, with a high yield (&gt;70%). The glucose solution produced in this process has a high concentration (&gt;100 g/L), which reduces the purification cost and makes the process industrially relevant. This method can be applied regardless of the quality of the fibers and could therefore process other cellulosic fibers such as viscose. The glucose produced could subsequently be fermented into butanediol or caprolactam, precursors for the production of synthetic textile fibers, thus retaining the value of the waste textiles within the textile value chain.