Catalyst For Synthesis Research Articles

Scalable synthesis of Robust, high-loading nitrogen-infused intermetallic FePt@Pt (core@shell) catalyst for proton exchange membrane fuel cells

In this study, we propose PtFeIMN@Pt/C, featuring a Pt shell on a nitrogen-infused PtFe intermetallic core structure, and attempt large-scale synthesis of catalysts with high metal content (>50 wt%). Using the ultrasound-assisted polyol synthesis method, we synthesize core@shell structured PtFe@Pt/C catalysts with approximately 60 wt% metal content at a 10 g scale in a single step. Post-treatments, including annealing, acid treatment, and nitriding in high-pressure NH3 gas, follow to synthesize the target catalysts. Optimizing the annealing temperature reveals a trade-off relationship affecting catalyst activity and durability. The PtFeIMN@Pt/C_600 °C, synthesized under optimized conditions, exhibits superior electrochemical performance and durability compared to commercial Pt/C catalysts. The accelerated stability test (AST) further shows significantly enhanced durability when nitrogen is included in the core. In the single cell tests, PtFeIMN@Pt/C_600 °C demonstrates approximately four times higher mass activity than commercial Pt/C catalysts and a 29.9 mV voltage drop at 0.8 A cm−2 after AST, meeting the U.S. Department of Energy's targets.

Revolutionizing acridine synthesis: novel core-shell magnetic nanoparticles and Co-Zn zeolitic imidazolate framework with 1-aza-18-crown-6-ether-Ni catalysts

Nanoparticles have emerged as a critical catalyst substrate due to their exceptional features, such as catalytic efficiency, high stability, and easy recovery. In our research, we have developed an innovative and environmentally friendly magnetic mesoporous nanocatalyst. Using the co-precipitation method, we produced magnetic nanoparticles (Fe3O4) and coated them with Zeolitic imidazolate frameworks (ZIFs) to enhance their surface area and chemical stability. The resulting substrate was functionalized with 1-aza-18-crown-6-ether and nickel metal. Our prepared catalyst has been rigorously evaluated using advanced techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmet-Teller (BET), vibrating sample magnetometry (VSM), scanning electron microscopy and energy dispersive X-ray (SEM-EDS), inductively coupled plasma (ICP), elemental mapping analysis (EMA), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). By synthesizing acridine derivatives, we have demonstrated the exceptional efficiency of our catalyst in organic compound synthesis. Through optimization, we have established the ideal parameters for catalytic processes, including catalyst amount, temperature, time, and ultrasonic use. Our catalyst has been proven to exhibit remarkable physical and chemical properties, such as porosity, temperature resistance, and recyclability. Notably, our heterogeneous nanocatalyst has shown outstanding performance and can be recycled six times without any loss in efficiency, affirming its potential in acridine.

MgCo2O4@g‐C3N4 Composite Induced Peroxymonosulfate Activation for Effective Degradation of Tetracycline Under Visible Light

AbstractThe composite Fenton catalyst was prepared by attaching MgCo2O4 to the surface of g‐C3N4 using a one‐pot method after preparing MgCo2O4 through co‐precipitation. The microstructure of the composites was analyzed using X‐ray diffraction (XRD) and other characterization methods. The catalytic activity of the composites towards tetracycline (TC) was studied, and a possible catalytic mechanism was proposed. The experimental results indicate that the degradation of TC by MgCo2O4@g‐C3N4 reached almost 99.0 % within 30 min in the presence of PMS and visible light. The combination of MgCo2O4 and g‐C3N4 improved the absorption of visible light, and the energy level‐matched heterojunction facilitated the separation of photogenerated electrons and holes, accelerating the redox cycle of ≡Co3+/≡Co2+. The free radical quenching experiment confirmed that the main active substances were free radical ⋅O2− and 1O2. The one‐step synthesis of composite catalysts exhibits high catalytic performance and good stability, offering a potential solution for the efficient treatment of tetracycline wastewater.

Synthesis of Novel Pseudo-Enantiomeric Phase-Transfer Catalysts from Cinchona Alkaloids and Application to the Hydrolytic Dynamic Kinetic Resolution of Racemic 3-Phenyl-2-oxetanone.

Naturally occurring Cinchona alkaloids such as quinidine (QD)/cinchonine (CN) and their diastereomers, quinine (QN)/cinchonidine (CD), have been recognized as pseudo-enantiomeric pairs. Utilizing these pseudo-enantiomeric alkaloids as chiral resources provides complementary enantioselectivity in many asymmetric reactions. During the screening of Cinchona alkaloid phase-transfer catalysts (PTCs) in the hydrolytic dynamic kinetic resolution of racemic 3-phenyl-2-oxetanone (1) to tropic acid (2), we found that the introduction of a 4-trifluoromethylphenyl group at the vinyl terminus of BnQN significantly reduced the enantioselectivity to 41% enantiomeric excess (ee). The optimized structure of tetrahedral intermediates (TI, PTC + 1 + OH-) of hydrolysis obtained by density functional theory (DFT) calculations shows that the orientation of the quinoline and benzene rings of QD class PTC are nearly parallel to each other and to construct a greatly extended π-electron cloud surface, allowing good π-π interaction with the benzene ring of 1.

In-situ biosynthesis of metallic nanoparticles using Allium sativum and Chondrilla juncea extract: characterization and application in dye decolorization

The synthesis of catalysts has gained specific concern due to their versatile applications in particular azo dye decolorization. In the current work, metallic nanoparticles (copper and silver) were In-situ biosynthesised using Allium sativum and Chondrilla juncea extract. The obtained Allium-copper oxide and Allium-silver oxide materials were analyzed using SEM, TEM, FT-IR, TGA-DTG, SEM, TEM, and XRD techniques. Allium peels had a rough surface, with nanoparticles equally distributed over it. The crystal structure of Allium peels was altered after the addition of CuO and AgO nanoparticles. The highest residual mass values in the prepared materials indicated that the metallic nanoparticles were, in situ, formed. The prepared materials had worse thermal stability than Allium peel powders. The azo dyes, Calmagite and Naphthol Blue Black B were tested in the catalytic power of the resulting materials. The decolorization process was affected by the dye structure, amount of H2O2, dye concentration, time of reaction, and temperature of the bath. The activation energy values for Allium-CuO were 18.44 kJ mol−1 for calmagite, and 23.28 kJ mol−1 for naphthol blue black, respectively. Nevertheless, the energy values for Allium-AgO were 50.01 kJ mol−1 for calmagite and 12.44 kJ mol−1 for Naphthol blue black. The calculated low energy values for the prepared materials suggested the high efficiency of the use of these catalysts in azo dye decolorization under the change of some main experimental conditions.

Theoretical Catalyst Screening of Multielement Alloy Catalysts for Ammonia Synthesis Using Machine Learning Potential and Generative Artificial Intelligence

Theoretical Catalyst Screening of Multielement Alloy Catalysts for Ammonia Synthesis Using Machine Learning Potential and Generative Artificial Intelligence

In situ decorated pd NPs on Triazin-encapsulated Fe3O4/SiO2-NH2 as magnetic catalyst for the synthesis of diaryl ethers and oxidation of sulfides

This article is devoted to the synthesis of a new magnetic palladium catalyst that has been immobilized on A-TT-Pd coated-magnetic Fe3O4 nanoparticles. Such surface functionalization of magnetic particles is a promising method to bridge the gap between heterogeneous and homogeneous catalysis approaches. The structure, morphology, and physicochemical properties of the particles were characterized through different analytical techniques, including TEM, FT-IR, XRD, SEM, EDS, TGA-DTG, ICP, and VSM techniques. The obtained Fe3O4@SiO2@A-TT-Pd performance can show excellent catalytic activity for the synthesis of diaryl ethers and oxidation of sulfides, and the corresponding products were obtained with high yields. The advantages of this catalyst include a simple test method, green reaction conditions, no use of dangerous solvents, short reaction time, low catalyst loading, and reusability. Also, the nanocatalyst was easily separated from the reaction mixture with the help of a bar magnet and recovered and reused several times without loss of stability and activity.

Dynamic Reconstruction of Cu Catalyst under Electrochemical NO Reduction to NH3.

The electrochemical reduction of nitric oxide (NO) to ammonia (NH3) offers a sustainable way of simultaneously treating the air pollutant and producing a useful chemical. Among catalyst candidates, Cu emerges as a stand-out choice for its superb NH3 selectivity and production rate. However, a comprehensive study concerning its catalytic behaviorin the NO reduction environment is lacking. Here, we unravel the dynamic rearrangement of Cu catalysts during NO reduction: the emergence of a bundled nanowire structure dependent on the applied potential. This unique structure is closely linked to an enhancement in double-layer capacitance, leading to a progressive increase in current density from 236 mA cm-2 by 20% over 1 h, while maintaining a Faradaic efficiency of 95% for NH3. Characterizations of Cu oxidation states suggest that the nanostructure results from the dissolution-redeposition of Cu in the aqueous electrolyte, influenced by the interaction with NO or other reactive intermediates. This understanding contributes to the broader exploration of Cu-based catalysts for sustainable and efficient NH3 synthesis from NO.

Immobilization of carbon composite materials on structured frameworks for application in continuous catalytic experiments: Application in NO3- conversion

Bimetallic catalysts applied for water treatment are highly susceptible to deactivation/poisoning mainly when immobilized in macroscopic structures. Metal support interaction characteristic of metal oxides/composite supports emerges as an important strategy for controlling this phenomenon.This work explores a novel washcoating methodology to synthesize macrostructured composite catalysts for selective nitrate reduction. This approach allowed to effectively integrate powder composite materials into macroscopic frameworks, allowing to take advantage of modifications performed in the powder materials, often associated with increased catalytic activity/selectivity.Pd-Cu composite materials (metal oxides with carbon nanotubes) were prepared/tested for nitrate conversion. Titanium dioxide composites achieved the best performance (54 % nitrate conversion and 61 % N2 selectivity), outperforming the results obtained with more conventional synthesis methodologies. The catalysts proved to be highly active and resistant over several hours of reaction. This is a pioneering work focused on the synthesis and application of macrostructured composite catalysts in G-L-S (gas-liquid-solid) treatment systems.

Synthesis and Electrochemical Characterization of Ru-Modified Iridium Oxide Catalysts for PEM Electrolysis

Synthesis and Electrochemical Characterization of Ru-Modified Iridium Oxide Catalysts for PEM Electrolysis

Nanoflower-like NiCoFe layered hydroxide by in-situ electrochemical corrosion as highly efficient electrocatalyst for water oxidation

Layered double hydroxides have been widely applied for oxygen evolution reaction (OER) in the alkaline water electrolysis. However, the issues of poor connection between the catalyst and nickel foam and the specific mechanisms for active sites has not been fully documented. In this study, the in-situ nickel foam etching in a mixed solution of ferric chloride and cobalt nitrate at low temperatures was adopted for NiCoFe layered ternary hydroxides (NiCoFe LTHs) synthesis with a better tight integration. Physicochemical characterization indicated that the NiCoFe LTHs could grow directly through corroding nickel foam with a nano-flower-like morphology and structures. That is favorable for electron transfer from the catalytic layer to the conductive substrate. With the transition metal ions interaction and the tight integration construction, NiCo1Fe4-LTH-T60/NF presented an enhanced electrolysis performance with the overpotential of 234 mV (1.464 V vs. RHE) at current density of 100 mA cm−2 in 1 M KOH electrolyte. The Tafel slope for NiCo1Fe4-LTH-T60/NF electrode was 36.19 mV dec−1 for an enhanced OER kinetics. Besides, it demonstrated faster interfacial charge transfer process, better intrinsic electrochemical activity and stability in large current stability testing. It was revealed that the synergistic effect of the transition metal ions interaction enhancement and the mechanism of oxygen evolution elementary reaction for NiCo1Fe4-LTH-T60/NF during the water electrolysis by the electrochemical and theoretical calculation. This work provides theoretical basis and experimental support for the design and synthesis of future OER catalyst and substrate, which is significant for hydrogen and oxygen generation from water electrolysis.

Facile and Environmentally Friendly Synthesis of Ga2O3/MFI Catalysts for Propane Dehydrogenation.

A GaOx-based catalyst is recognized as a promising catalyst for dehydrogenation of light alkanes. Conventionally, impregnation and calcination are necessary processes for the loading of GaOx. However, the incomplete impregnation of gallium salt solution would generate wastewater, and the calcination for the dissociation of gallium salt would release harmful gases, such as SOx, NOx, and HCl. Meanwhile, the high temperature results in an excessive energy cost and undesired GaOx particle aggregation. Here, we report a facile and environmentally friendly method for the synthesis of GaOx-based catalysts. The gallium salt solution was replaced directly with liquid gallium (LG). Through a simple physical mixing method at room temperature, uniform GaOx nanoparticles with diameters of around 3.5 nm were loaded onto the surface of silicalite-1 (S-1). With the optimal GaOx/MFI catalyst, the propane conversion and propylene selectivity reached 22.9 and 90.1%, respectively, in the propane dehydrogenation reaction. The work offers a clean and economical strategy utilizing liquid metal (LM) as an impregnation solution for the preparation of GaOx-based catalysts.

Designing plausible catalysts for synthesis of zingerone from vanillin and acetone via aldol condensation reaction on O-terminated M3C2-MXenes

Herein, high-performance O-terminated M3C2 MXene catalysts were screened for the synthesis of zingerone using vanillin and acetone. The electrochemical and electronic properties of O-terminated ordered MXenes in the form of M3C2O2(H) [M = Ti, V, and Cr (3d); Zr, Nb, and Mo (4d); and Hf, Ta, and W (5d)] were investigated using first principle density functional theory (DFT) calculations. These calculations revealed 37 stable candidates based on their negative binding energy values of ΔG*H and three O-terminated M3C2 MXene candidates with superior zingerone synthesis activity than pure precious metal (platinum), a UL > −0.4 V can guarantee high activity and low energy consumption during zingerone synthesis. Ti3C2O (FCC)), Hf3C2O2 (HCPFCC), and Nb3C2O2 (HCPHCP) exhibited higher catalytic activity than other candidates, and their performances were competitive for zingerone synthesis, with low limiting potentials of −0.37, −0.27, and −0.35 V, respectively. Zingerone synthesis via the protolysis reaction between vanillin and acetone includes two paths, i.e., induced protolysis and direct protolysis via the aldol condensation reaction. Multiple descriptors were used to evaluate and screen promising candidates for the synthesis of zingerone. For example, ΔG(*vanillin*acetone), and Bader charge, and d-band center analyses revealed the origin of zingerone synthesis activity based on binding energy and electronic structure. Importantly, binding energy and electronic structure have a strong intrinsic linear scaling relationship that can be used to screen for the optimal catalyst by controlling the scaling relationship between the intermediate binding energy and electronic properties. Indicating a scaling relationship and volcano plot were established based on ΔG(*vanillin+*acetone) and ΔG[*zingiberone] depending on Limiting potential (UL). Finally, we proposed a method for directly inducing protolysis during the aldol condensation reaction, which may be widely applicable to different biomass-derived carbonyl compounds, yielding chemicals and medicinal compounds through biomass valorization.

Efficient electrocatalytic urea synthesis from CO2 and nitrate over the scale-up produced FeNi alloy-decorated nanoporous carbon

Electrocatalytic urea synthesis provides a favorable strategy for conventional energy-consuming urea synthesis, but achieving large-scale catalyst synthesis with high catalytic efficiency remains challenging. Herein, we developed a simple method for the preparation of a series of FeNi-alloy-based catalysts, named FeNi@nC-T (n represents the content of nanoporous carbon as 1, 3, 5, 7 or 9 g and T = 900, 950, 1000 or 1100 °C), for highly performed urea synthesis via NO3− and CO2 co-reduction. The FeNi@7C-1000 achieved a high urea yield of 1041.33 mmol h−1 gFeNi−1 with a Faradaic efficiency of 15.56% at –1.2 V vs. RHE. Moreover, the scale-up synthesized FeNi@7C-950-S (over 140 g per batch) was achieved with its high catalytic performance and high stability maintained. Mechanism investigation illuminated that the Ni and Fe sites catalyze and stabilize the key *CO and *N intermediates and minimize the C–N coupling reaction barriers for highly efficient urea synthesis.

Regulation of Surface Oxygen Vacancies on Ce-Based Catalysts for Dimethyl Carbonate Direct Synthesis from CO2 and CH3OH

Regulation of Surface Oxygen Vacancies on Ce-Based Catalysts for Dimethyl Carbonate Direct Synthesis from CO₂ and CH₃OH

Unveiling the Synthesis of a Zirconium-Substituted Copper Bismuth Oxide Catalyst for Visible Light-Responsive Photocatalytic Degradation of Persistent Organic Dye

Unveiling the Synthesis of a Zirconium-Substituted Copper Bismuth Oxide Catalyst for Visible Light-Responsive Photocatalytic Degradation of Persistent Organic Dye

CO2-assisted Controllable Synthesis of PdNi Nanoalloys for Highly Selective Hydrogenation of Biomass-derived 5-Hydroxymethylfurfural.

The selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-bishydroxymethyltetrahydrofuran (BHMTHF), a vital fuel precursor and solvent, is crucial for biomass refining. Herein, we report highly selective and stable PdNi nanoalloy catalysts for this deep hydrogenation process. A CO2-assisted green method was developed for the controllable synthesis of various bimetallic and monometallic catalysts. The PdNi/SBA-15 catalysts with various Pd/Ni ratios exhibited a volcano-like trend between BHMTHF yield and Pd/Ni ratio. Among all catalysts tested, Pd2Ni1/SBA-15 achieved the best performance, converting 99.0% of HMF to BHMTHF with 96.0% selectivity, surpassing previously reported catalysts. Additionally, the Pd2Ni1/SBA-15 catalyst maintained excellent stability even after five recycling runs. Catalyst characterizations (e.g., HAADF-STEM) and DFT calculations confirmed the successful formation of the alloy structure with electron transfer between Ni and Pd, which accounts for the remarkable performance and stability of the catalyst. This work paves the way for developing highly selective and stable alloy catalysts for biomass valorization.

Molybdenum Disulfide-Based Catalysts in Organic Synthesis: State of the Art, Open Issues, and Future Perspectives.

In the field of heterogeneous organic catalysis, molybdenum disulfide (MoS2) is gaining increasing attention as a catalytically active material due to its low toxicity, earth abundance, and affordability. Interestingly, the catalytic properties of this metal-based material can be improved by several strategies. In this Perspective, through the analysis of some explicative examples, the main approaches used to prepare highly efficient MoS2-based catalysts in relevant organic reactions are summarized and critically discussed, namely: i) increment of the specific surface area, ii) generation of the metallic 1T phase, iii) introduction of vacancies, iv) preparation of nanostructured hybrids/composites, v) doping with transition metal ions, and vi) partial oxidation of MoS2. Finally, emerging trends in MoS2-based materials catalysis leading to a richer organic synthesis are presented.

Ni‐MOF‐74 Derived Carbon‐Based Ni Catalysts for Efficient Catalytic Ammonia Synthesis via Pulsed DBD Plasma

ABSTRACTDesigning efficient noble metal‐free catalysts for plasma‐catalytic ammonia synthesis is significant and challenging. Carbon‐based metal catalysts were prepared at different pyrolysis temperatures using the Ni‐MOF‐74 precursor. The effects of Ni‐MOF‐74 and its derived carbon‐based metal catalysts on pulsed dielectric barrier discharge (DBD) plasma ammonia synthesis were investigated. The results showed that Ni‐MOF‐74‐300 with both the MOF structure and nickel metal particles exhibited the best catalytic performance for ammonia synthesis. The ammonia synthesis rate reached 41.38 mmol g−1 h−1, whereas the nitrogen conversion rate was as high as 1.54% with an energy yield of 3.04 g kWh−1. Compared to the situation of plasma only, the ammonia synthesis rate, nitrogen conversion rate, and energy yield were increased by 28.46 times, 5.7 times, and 5.5 times, respectively.

Spatially Immobilized PtPdFeCoNi as an Excellent Bifunctional Oxygen Electrocatalyst for Zinc–Air Battery

AbstractDeveloping efficient oxygen electrocatalysts with low cost, high catalytic activity, and robust stability remains a formidable challenge for rechargeable zinc–air batteries (ZABs). Herein, highly dispersed ultrasmall PtPdFeCoNi high‐entropy alloy nanoparticles with a size of ≈ 2 nm and randomly distributed multimetallic single atoms spatially immobilized on the 3D hierarchically ordered porous nitrogen‐doped carbon skeleton (denoted as PtPdFeCoNi/HOPNC) are successfully synthesized via ultra‐rapid Joule heating process. The spatial immobilization on 3D HOPNC skeleton is the key to the high dispersion of multi‐active sites of oxygen electrocatalysts, and the formed hierarchical pore structure is conducive to the successful construction of the rapid mass transfer channel. As a result, the as‐prepared PtPdFeCoNi/HOPNC exhibits a positive half‐wave potential of 0.866 V versus RHE for oxygen reduction reaction (ORR), a low overpotential of 310 mV at 10 mA cm−2 for oxygen evolution reaction (OER), and low Tafel slopes for both ORR and OER. Furthermore, ZAB using PtPdFeCoNi/HOPNC as bifunctional oxygen catalysts exhibits excellent rate performances and superior cycling stability, surpassing that of a commercial Pt/C‐RuO2 mixture. The spatial immobilization strategy of HOPNC provides a new idea for the design and synthesis of efficient catalysts for various applications.