A series of binder-free mordenite (MOR) zeolites were synthesized via seed-assisted hydrothermal crystallization. To further investigate the influence of alkaline conditions on the morphology and acidity of binder-free MOR, NaOH was introduced into the liquid phase, and its amount was varied from 0.0 wt
This study reports the fabrication of a novel chiral electrode engineered for efficient asymmetric (enantioselective) electrochemical and direct cyanation of desired styrene derivatives. The mentioned electrode features copper nanoparticles (NPs) uniformly dispersed on graphene oxide functionalized with the chiral amino acid L-alanine, operating within a deep eutectic solvent (DES) system. The L-alanine modification introduces stereochemical bias, thereby improving the electrode’s enantioselectivity in electro-organic synthesis. The synergistic interaction among Cu NPs, modified GO, and DES enables efficient, selective transformation of styrenes into (R)-2-phenylpropanenitrile derivatives 4(a–j), achieving high enantioselectivity (88–97
Conventional syntheses of tocopheryl acetate rely on strong Brønsted/Lewis acids and energy-intensive conditions. Here we report a visible-light photocatalytic route using graphitic carbon nitride (g-C3N4) engineered by precursor control, P/S co-doping, metal loading (Cu, V, Zn, Ni), and nanosheet formation. Structural characterization by SEM and TEM revealed that P/S co-doping and exfoliation produced highly corrugated nanosheets with increased porosity, abundant edge sites, and reduced interlayer stacking. XRD analysis confirmed the preservation of the g-C3N4 framework with slight distortion upon doping, while HRTEM showed lattice disorder and defect formation that are beneficial for charge trapping and transfer. In ethanol/H2O2 under a 40 W lamp, P/S@g-C3N4 affords a 76.26
This work reports the preparation of magnetic biochar (biochar-Fe) derived from abundantly available sugar palm waste (Arenga pinnata) which is commonly cultivated and utilised in South-East Asia, especially in Indonesia. To generate surface acidity, biochar-Fe was functionalised with tungstophosphoric acid (TPA). Magnetic property of the prepared biochar is confirmed by the visual inspection and corroborated by the vibrating sample magnetometer (VSM) measurement demonstrating a narrow hysteresis, a typical soft ferromagnetic material. X-ray diffraction (XRD) in combination with X-ray photoelectron spectroscopy (XPS) verifies the peaks representing Fe2O3 and Keggin’s structure of tungstophosphoric acid (TPA). The existence of TPA is also affirmed by its characteristic bands in the IR spectroscopy. Meanwhile, the deconvoluted XPS spectra suggests the presence of W6+ and Fe3+. NH3-TPD and acid–base titration emphasise a large increase of surface acidity following the TPA impregnation onto biochar-Fe. Catalytic activity of TPA/biochar-Fe is assessed in the synthesis of butyl levulinate (BL) via esterification of levulinic acid (LA). Comparable BL yield around 10–14
Nitrous oxide (N2O) is a strong greenhouse gas and an important ozone-depleting species. Direct catalytic decomposition is an attractive removal route because it does not require an external reductant and ideally produces only N2 and O2. In real exhaust streams, however, N2O is often accompanied by NO, which can strongly lower catalytic activity by competing for active sites, forming NOx-derived surface species, hindering oxygen migration, and slowing active-site regeneration. This review summarizes recent progress in direct N2O decomposition under NO-containing conditions, with emphasis on inhibition mechanisms, catalyst evaluation, and catalyst design for improved NO resistance. The discussion is organized by catalyst function rather than by material type, including suppression of stable NOx adsorption, promotion of oxygen migration and site recovery, control of local active-site structure, and multifunctional systems that provide mechanistic insights into NO transformation during NO-tolerant N2O decomposition. The review also discusses current challenges in mechanistic studies under working conditions, testing under realistic gas feeds, long-term stability, regeneration, and practical implementation. It aims to provide a clearer basis for designing catalysts with better NO tolerance.
Proton exchange membrane fuel cells (PEMFCs), as an efficient and clean energy conversion technology, face one of the core challenges to their commercial application: the sluggish kinetics of the cathodic oxygen reduction reaction (ORR), along with the high cost and limited stability of platinum (Pt)-based catalysts. Density functional theory (DFT) calculations serve as a bridge linking microscopic atomic structure to macroscopic catalytic performance, offering a powerful theoretical tool to deeply understand the ORR mechanism, uncover the origin of catalytic activity, and guide the rational design of high-performance Pt-based alloy catalysts.Based on a review of relevant domestic and international literature, this paper systematically summarizes the application and recent research progress of DFT calculations in the study of the oxygen reduction reaction on platinum-based alloys. It begins by elucidating key physicochemical descriptors derived from DFT calculations, including the adsorption energies of oxygen atoms and related intermediates (O*, OH*, OOH*), the d-band center theory as a core descriptor of electronic structure, surface vacancy formation energy, and the critical role of lattice strain effects in modulating catalytic activity. By synthesizing the current state of research, it also outlines design principles for optimizing catalyst electronic and geometric structures through strategies such as strain engineering. Furthermore, this review discusses the microscopic ORR mechanisms (e.g., dissociative and associative mechanisms) and analyzes the synergistic validation relationship between theoretical predictions and experimental synthesis and performance characterization. Finally, this review summarizes current challenges in the field, including the simplification of computational models and the need to account for solvation effects and dynamic behavior. Future research directions are also outlined, including the integration of high-throughput computing with machine learning, multiscale simulations, and the theoretical interpretation of advanced in-situ characterization techniques, aiming to provide theoretical guidance for designing novel, efficient, stable, and low-cost ORR electrocatalysts.
Tungsten oxide-based superacid catalysts (WO3, SO42⁻/WO3, GO/WO3, and GO/SO42⁻/WO3) were synthesized via a green, sustainable route using sugarcane bagasse-derived graphene oxide and ammonium persulfate as an eco-friendly sulfate precursor, and applied to the catalytic conversion of isopropanol as a diagnostic probe reaction for surface acid–base characterization. Structural and textural properties were thoroughly investigated by XRD, FE-SEM, FTIR, BET surface analysis, TGA, and non-aqueous potentiometric titration. XRD confirmed the monoclinic WO₃ phase across all samples, while potentiometric titration revealed a dramatic enhancement in surface acid strength upon sulfation, with the initial electrode potential rising from + 18 mV for bare WO₃ to + 530 mV for SO₄2⁻/WO3 and + 257 mV for the ternary GO/SO42⁻/WO3 composite (GSW), both qualifying as superacid materials. Catalytic performance at 100 °C demonstrated that GSW achieves the highest IPA conversion (97.8
The current review presents a survey on the recent developments in the field of magnetic nanocatalysts for efficient and green synthesis of the chromene-3-carbonitrile derivatives by multicomponent reactions. Different types of magnetic nanoparticles, such as Fe3O4-based cores which can be functionalized with silica, Schiff base complexes, metal dopants (Cu, Co, Mo, Pd), and bio-based supports (mica, agar, kaoline), have been designed to catalyze Knoevenagel condensation, then Michael addition and cyclization under mild, solvent-free or environmentally benign conditions. It is worth noting that the dendrimeric oxo-vanadium phthalocyanine, copper ferrite, molybdenum Schiff base complexes, and hybrid ZnS/CuFe2O4/agar systems are among the catalysts that are highly active, selective, and reusable, with the yields of most programs reaching over 90
Copper oxide (CuO) thin films were successfully prepared by electrodeposition and hydrothermal techniques to explore their structural, morphological, and electrochemical properties for catalytic use. The electrodeposited films showed dense and homogeneous morphologies with high substrate adhesion, whereas the hydrothermal process yielded hierarchical nanostructures with increased surface area. X-ray diffraction analysis confirmed the purity of the CuO phase, and UV-Vis diffuse reflectance spectroscopy showed a reduced band gap of 1.214 eV for hydrothermally synthesized CuO, which is beneficial for efficient charge carrier transport. Scanning electron microscopy analysis revealed that hydrothermally synthesized CuO had a very porous structure, which is conducive to high electrocatalytic activity. Electrochemical analysis showed that hydrothermally synthesized CuO had the lowest overpotential of 540 mV (vs. RHE) at 10 mA/cm2 and a lower Tafel slope of 65.2 mV/dec, along with improved durability of up to 11 h. The enhanced oxygen evolution reaction (OER) performance is ascribed to the high crystallinity, increased active surface area, and improved charge transfer rate of hydrothermally synthesized CuO. These results clearly demonstrate the effectiveness of the hydrothermal process for preparing CuO-based catalysts for OER and renewable energy conversion.
Constructing hierarchical structure in conventional zeolites is a promising means to overcome intrinsic shortcomings of this type of microporous material. In this research, a novel synthesis strategy for hierarchical zeolite was presented. By utilizing hexagonal mesoporous silica (HMS) as silica source, MFI aluminosilicate with mesoporosity was successfully prepared through sustainable process without conventional organic template or large amounts of solvent. The obtained products were characterized by a series of techniques, including X-ray diffraction, transmission electronic microscopy, N2 physical adsorption, X-ray fluorescence and NH3 temperature programmed desorption. It has been shown that as-synthesized and calcined HMS had generated MFI zeolite with different mesoporosity, based on which the different synthesis mechanisms for hierarchical products were proposed. The alkylamine dose not impede the sustainable synthesis of MFI zeolite, which endow the availability of HMS for green synthesis of hierarchical zeolite. After loaded with platinum, the obtained hierarchical bifunctional catalysts show higher activity but lower isomers selectivity in hydroisomerization of n-heptane compared to mono-microporous counterpart. In addition, the mesoporosity of the catalysts had led to the higher multi-branched isomers productivity.
Precise control over the acidic properties and pore architecture of zeolites is essential for the rational design of high-performance catalysts. Here, we demonstrate that simple post-synthetic treatment with ethanol solution can effectively reduce both strong and weak acid sites in silicoaluminophosphate (SAPO) zeolites. The hydroxyl groups in ethanol interact with terminal hydroxyls associated with Si islands and with bridging hydroxyls in Si–OH–Al species, leading to the elimination of these acid sites. Compared with the parent sample (S-P), the ethanol-treated sample (S-E3) retains only 34.4
The continuous wastewater pollution due to organic dyes needs to be urgently addressed via an effective and environmentally friendly approach. The present research explores the synthesis of copper sulfide (CuS) and iron sulfide (FeS) chalcogenides via green synthesis (using onion extract) and chemical method for wastewater treatment. The green-synthesized CuS and FeS showed greater photocatalytic activity due to the small size of CuS-G and FeS-G chalcogenides around 5.27 and 6.67 nm, and a small band gap of about 2.63 and 2.87 eV, respectively. The synthesized CuS-C and CuS-G chalcogenides showed 89.13 and 89.07
Nowadays, modern nanotechnology has emerged as an important tool in advanced photocatalysis research, providing innovative protocols for wastewater treatment. In this study, zinc cobaltite nanoparticles (ZnCo2O4 NPs) were prepared via an eco-friendly, straightforward approach using cow urine (CU), a natural bio-reductant and bio-stabilizer. The topological, optical, and structural features of the as-produced ZnCo2O4 NPs were properly characterized using XRD, Raman spectroscopy, HRTEM, UV-DRS, XPS, FTIR, and EDX. The XRD investigation revealed that ZnCo2O4 NPs with an average crystallite size of 28.27 nm were produced in the face-centered cubic spinel phase. TEM revealed the irregular polyhedral shape of ZnCo2O4 NPs. The UV-DRS technique indicates that the electronic band gap of ZnCo2O4 NPs is 2.38 eV. To assess the photocatalytic performance of ZnCo2O4 NPs, Rhodamine B (RhB) was chosen as a representative contaminant. The ZnCo2O4 NPs revealed excellent photocatalytic efficacy toward the decomposition of RhB dye beneath solar light irradiation. A maximum decomposition performance of 93.66
Polymetallic Mo–Ni, Mo–Co, and Mo–Ni–Co catalysts were prepared by gravity-assisted SHS metallurgy followed by alkali leaching of aluminum from intermetallic precursors. The catalysts were characterized by XRD, SEM/EDS, H2-TPR, FTIR, and nitrogen sorption method and tested in CO2 hydrogenation under normal and enhanced pressure. Conversion of CO2 to CO, CH4 and higher hydrocarbons is ruled by catalyst nature, temperature, pressure, and H2 to CO2 molar ratio in feed gas. Ni-containing catalysts convert CO2 to CH4 selectively at 200–350 °C under atmospheric pressure. Mo–Co and Mo–Ni–Co catalysts provide high selectivity to liquid hydrocarbons (yield up to 27
The aggregation of TiO2 precursors affects the structural evolution and catalytic performance of sulfated titania, highlighting a relationship between microscale and macroscale reactivity. In the present work, the sulfated titania (TiO2/SO42-) solid acid catalysts were synthesized through the impregnation approach using two different precursors, pre-aggregated TiO2 (microscale) and molecular-scale Ti(OH)4. The catalysts were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, and ammonia temperature-programmed desorption (NH3-TPD). Their catalytic activity was tested in the transesterification reaction of ethyl acetate with n-butanol. The TiO2/SO42- derived from Ti(OH)4 precursor exhibited a single-phase anatase structure with (92%) higher specific surface area (63.85 m2g- 1 vs. 33.38 m2g- 1), smaller crystallite size (8.05 nm), and higher catalytic conversion (70%) as compared to the catalyst prepared from pre-aggregated TiO2. These differences are attributed to variations in precursor aggregation, which influence crystallite growth, sulfate dispersion, and surface area acidity, thereby enhancing catalytic performance during transesterification. The present work establishes a link between TiO2 precursor aggregation and the catalytic activity of TiO2/SO42-. The results demonstrate that the aggregation state of the TiO2 precursor inherently governs the physicochemical characteristics and catalytic behavior of sulfated titania, providing a rational basis for tailoring solid acid catalysts for esterification and transesterification reactions.
Antibiotic poisoning of water has arisen as a significant environmental issue that researchers have paid particular attention to in recent years. This study focuses on the development of a magnetite/cellulose nanocomposite derived from date palm fiber for the efficient removal of ciprofloxacin (CIP) from wastewater using both adsorption and Photo-Fenton processes. The developed nanomagnetite/biopolymer-based composite is thought to be able to effectively remove antibiotics from aqueous solutions by combining adsorption and photodegradation because of its large surface area, functional groups, and catalytic activity. The structural and surface properties of these materials were characterized by using various physicochemical techniques. The magnetic/cellulose nanocomposite exhibited good thermal stability, diverse surface functional groups, a point of zero charge (pHPZC) of 6.5, a relatively high specific surface area (103.4 m2g−1), mesoporous structure with an average pore radius of 2.17 nm, a low energy band gap of 2.4 eV, and an average particle size of approximately 10 nm as observed by TEM. The results show that NgC exhibited the highest adsorption capacity (Xm = 146.68 mg g−1) at 22 °C, pH 8, with a dosage of 2 g L−1 and an equilibrium time of 2 h. The adsorption of CIP onto all solid adsorbents followed the pseudo-second-order, Langmuir, and Temkin nonlinear models, indicating an endothermic and spontaneous process. CIP degradation using NgC via the Photo-Fenton process achieved 100
The catalytic performance of Cu-Fe-LDH (LDH: layered double hydroxide) was tested for the degradation of the veterinary antibiotic, oxytetracycline hydrochloride (OTC-HCl), in catalytic wet air oxidation (CWAO) process. Box–Behnken design and the response surface methodology were used to study the effects of catalyst dosage, pH, and reaction temperature on OTC-HCl removal efficiency. The optimal CWAO conditions were determined by maximizing the degradation efficiency of OTC-HCl. Under the optimum reaction conditions (0.5 g/L Cu-Fe-LDH catalyst loading, pH 7, atmospheric pressure, and 70 °C reaction temperature) 91.75
Heck coupling reaction is widely employed in organic synthesis for the preparation of natural products, agrochemicals, and pharmaceutical and biologically active compounds. Heck coupling assists the reaction between aryl halides and alkene in the presence of palladium catalyst and phosphine ligands. The high cost of palladium makes it necessary to recycle the palladium catalyst. In the quest for developing an eco-friendly synthetic approach, a biopolymer and phytochemical-supported palladium heterogeneous catalyst has been explored due to its non-toxicity, abundance, and cost-effectiveness. Biopolymer decorated nanocatalysts play a significant role in the Heck coupling reactions by improving stability, recyclability, product yield, and selectivity. This review highlights recent progress in animal and plant-derived polysaccharides and phytochemical-decorated Pd nanocomposites for Heck coupling, focusing on substrate scope, catalytic performance, and recyclability. Besides, this article provides key insight for advancing sustainable organic transformations towards the development of therapeutic agents using green nanocatalysts.
Vanadium-catalyzed alkene epoxidation has emerged as a versatile and robust approach for the synthesis of epoxides, which are indispensable intermediates in organic synthesis, pharmaceutical development, and natural product chemistry. This review article surveys key advances in epoxidation methodologies employing vanadium-based catalysts, with particular emphasis on widely used systems such as vanadyl acetylacetonate and vanadium oxytriisopropoxide. Attention is given to the use of environmentally benign oxidants, notably hydrogen peroxide and tert-butyl hydroperoxide, as well as to alternative reaction media including ionic liquids and supercritical carbon dioxide. Mechanistic features governing reactivity, selectivity, and asymmetric induction are discussed alongside recent developments in ligand design and catalyst robustness. Collectively, these studies highlight the synthetic utility of vanadium catalysis while underscoring ongoing efforts to enhance selectivity, broaden substrate scope, and improve sustainability.
The delafossite CuCrO2 exhibits a piezo-photo-electrocatalytic activity for the oxidation of Methyl Green (MG), under sunlight. It was synthesized by sol–gel route with an increased surface/volume ratio; the porosity is shown by the SEM analysis, the particles consist of a combination of spherical and dendritic grains, with an average size ranging from 0.2 to 1.5 μm. The direct transition (1.93 eV) is attributed to Cr3+: t2g – eg transition of CrO6 octahedra layers parallel to the (a, b) plane, giving CuCrO2 an anisotropic structure with reversible oxygen intercalation/desintercalation. The Intensity-Potential J(E) profile in Na2SO4 (3.5 g L-1) shows a small hysteresis loop, indicating good electrochemical stability with a high oxygen over-potential and the capacitance plot suggests p-type conduction and the acceptor states (Cu2+) originate from oxygen insertion into the layered lattice. The free potential is more cathodic than the flat band potential (Efb) of – 0.045 V, leading to spontaneous photocatalysis. The conduction band (– 1.75 V) reduce O2 to O2•- radical and as application 66
