Efficient Catalyst Research Articles

Nanostructured Iron (III)-Copper (II) Binary Oxide as a Highly Efficient Magnetically Recoverable Nanocatalyst for Facile One-pot Synthesis of 2, 4, 5-trisubstituted Imidazole and 1, 4-dihydro Pyridine Derivatives under Solvent-free Conditions

Abstract: The Fe (III)-Cu (II) binary oxide magnetic nanocatalyst emerges as an environmentally friendly and highly efficient solid acid catalyst, demonstrating remarkable utility in the one-pot synthesis of 2, 4, 5-trisubstituted imidazole and 1,4-dihydropyridine compounds, all achieved under solvent-free conditions. A facile co-precipitation method was used to synthesize nanostructured Fe-Cu binary oxide. Notably, this Fe-Cu binary oxide magnetic nanocatalyst proves its eco-friendly credentials as an exceptionally efficient and reusable catalyst, offering ease of handling, recovery, and multiple uses with minimal reactivity loss. Furthermore, the Fe (III)-Cu (II) binary oxide magnetic nanocatalyst's magnetic separability enhances its practicality, allowing for effortless catalyst retrieval after reactions. Significantly, the structural characteristics are meticulously elucidated through advanced analytical techniques, including 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. This work presents a versatile and sustainable solution for catalysis, with wide-reaching implications for green chemistry and the development of reusable, efficient catalysts for organic synthesis. The exceptional performance and eco-friendliness of the Fe-Cu binary oxide magnetic nanocatalyst underscore its practical significance. Fe-Cu binary oxide magnetic nanocatalyst exhibits the highest catalytic activity compared to others. The employment of this catalyst consistently delivers excellent yields in the target reactions, highlighting its potential to contribute positively to sustainable chemical processes.

An Efficient Propylphosphonic Anhydride (T3P®)-Mediated MW-induced Solvent-free Rapid Synthesis of Enamino Esters and Ketones including 5, 5-Dimethyl-3-aminocyclohex-2-enones

Abstract: This work presents a clean and convenient synthesis of various β-enaminones including 5,5- dimethyl-3-aminocyclohex-2-enones, in satisfactory to excellent yields from the condensation reaction of primary amines with β -dicarbonyls by employing T3P® as a catalyst and performing the reaction under microwave irradiation and solvent-free conditions. These rapid reactions launched readily and stood a diversity of organic functional groups. A mixture of 1,3-dicarbonyl compound, primary amine and T3P® (50% in AcOEt) was irradiated for an appropriate time under microwave at 80°C. After completing the reaction (TLC) and cooling to r.t., ethyl acetate and saturated aqueous NaHCO3 solution were added. The aqueous phase was extracted ethyl acetate. The combined organic layer was washed with brine, dried over Na2SO4, and filtered, and the solvent was removed under reduced pressure to afford the product, which was recrystallized from diisopropyl ether. The presented results exhibit a better catalytic activity of T3P in the synthesis of enaminones. It could be concluded that T3P is the best catalyst as it took only a few minutes for the completion of the reaction with an excellent yield of product, which indicates T3P is more efficient, compared to other catalysts. A comparison of the efficiency of the present procedure with some heterogeneous solid catalysts was evaluated as well. Clearly, a higher yield was established in this procedure compared to other catalysts. Furthermore, the reaction of amines with dimedone was investigated as well, delivering excellent yields. The reaction catalyzed by T3P under microwave irradiation supplies a comprehensive method for the synthesis of enaminones. In this work, T3P is an effective, efficient and green catalyst, which forms the procedure economic, suitable, and safe with widespread application in the synthesis of enaminones. background: This work presents a clean and convenient synthesis of various β-enaminones incuding 5,5-dimethyl-3-aminocyclohex-2-enones in good to excellent yields from the reaction of different primary amines with 1,3-dicarbonyl compounds by employing T3P® as a catalyst and performing the reaction under microwave irradiation and solvent-free conditions. This one-pot rapid reaction proceeded readily and tolerated a variety of functional groups.

Binary nonmetal boron and phosphorus co-doping into PdRh nanosheets boosts electro‑upgrading polyethylene terephthalate

The upcycling of plastic waste through electrochemistry has garnered significant interest. In this study, we present a two-step strategy for synthesizing boron (B) and phosphorus (P) co-doped quaternary PdRhBP nanosheets (PdRhBP NSs) aimed at converting polyethylene terephthalate (PET) plastic hydrolysate (ethylene glycol) into high-value-added chemicals. The electrocatalytic performance of PdRhBP NSs for ethylene glycol (EG) oxidation surpasses that of PdRh NSs and commercial Pd black. Notably, the highest contents of glycolic acid (GA) and formate are observed at a voltage of 0.755 V. This can be attributed to the two-dimensional structural advantages of PdRhBP NSs and the synergistic effect of B and P, optimizing the electronic configuration of Pd. This study not only proposes a double-doping strategy for designing efficient electrochemical conversion catalysts but also presents a green and sustainable approach for upgrading and utilizing plastic waste.

Surface state modulation of carbon dots for efficient generation of hydrogen peroxide

Electrocatalytic dual electron oxygen reduction to hydrogen peroxide (2e ORR) is considered a special and sustainable method for on-site continuous production of hydrogen peroxide. Oxygen doped carbon based materials have demonstrated their superiority in the generation of H2O2. However, there is still a lack of direct experimental evidence to determine the true active site on complex carbon surfaces. In this work, we introduce only carboxyl functional groups on the surface of carbon dots by a mild and simple synthesis method to study the specific COOH functional groups on the generation of H2O2. The H2O2 selectivity was correlated with the contents of COOH functional groups. In alkaline environments, the citric acid modified CDs (CA-OCDs) own excellent catalytic ability for 2e ORR, showing a maximum starting potential of 0.829 V (vs. RHE) and a high selectivity of 89.7% over a wide potential range of 0.2-0.7 V (vs. RHE). In actual H2O2 production, the Faraday efficiency (FE) of CA-OCDs can be up to 97%, and the yield achieves 838 mmol gcatalyst-1 h-1. This work provides an effective and simple strategy for designing efficient carbon-based catalysts for sustainable H2O2 electrosynthesis.

Ce-doped LaMnO3-δ perovskite as an efficient ozonation catalyst for the degradation of high-concentration phenol wastewater

In this study, a series of La1−xCexMnO3-δ (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0) perovskites with different Ce doping ratios were synthesized by the citrate sol-gel method for catalytic ozonation degradation of phenol at high concentration. Among them, the La0.9Ce0.1MnO3-δ catalyst showed the best catalytic performance, increasing COD removal nearly three times compared with ozonation alone. The COD removal of the catalysts was 0.1 > 0.3 > 0 > 0.5 > 0.7 > 0.9 > 1.0, which corresponded to COD removal of 67.56%, 58.12%, 57.94%, 53.68%, 52.18%, 49.19%, and 39.24%, respectively. SEM, BET, and XRD characterized the structural performance of the catalysts. The two critical parameters of catalyst dosage and pH were also optimized. Simultaneous reproducibility experiments demonstrated the good reusability of the catalyst. In addition, the catalytic degradation mechanism was investigated by the qualitative and quantitative detection of free radicals, EPR, fluorescence detection, XPS and TPD/TPR tests, which indicated that the surface hydroxyl groups, oxygen vacancies, and Mn(Ⅲ)/Mn(Ⅳ) and Ce(Ⅲ)/Ce(Ⅳ) redox pairs on the surface of the catalysts were the potential active sites for the decomposition of ozone to ROSs. The doping of Ce can effectively increase the number of active sites and promote the electron cycling process, thus generating large amounts of •OH and O2-•, effectively mineralizing phenol.

Boosting peroxymonosulfate activation with a composite of highly dispersed FeS2 nanoparticles anchored on N-doped biochar for efficient tetracycline degradation

The rational design of inexpensive peroxymonosulfate (PMS) activators with high efficiencies is still in high demand. Herein, a composite with highly dispersed FeS2 anchored on nitrogen-doped biochar (FeS2@NBC) was prepared via a hydrothermal process and used for PMS activation to degrade the pollutant tetracycline (TC). Benefiting from in situ growth of FeS2 on the NBC surface, FeS2@NBC alleviated the side effects caused by FeS2 agglomeration, and the synergistic catalytic effect of the FeS2 nanoparticles and N-doped biochar resulted in excellent performance. The optimal FeS2@NBC/PMS system could degrade 87.6% of TC within 10min, and it exhibited adaptability to pH changes and the presence of common inorganic anions. A comprehensive study involving radical scavenging experiments, electron paramagnetic resonance (EPR) spectroscopy, electrochemical tests and XPS analyses revealed that the singlet oxygen (1O2) and hydroxyl radical (•OH) were the dominant reactive oxygen species (ROS), the sulfate radical (SO4•−) and electron transfer were involved in the TC degradation process. Moreover, three degradation pathways were indicated by LC−MS detection, and the toxicities of the degradation intermediates were predicted and evaluated. Finally, FeS2@NBC showed excellent reusability and stability after five cycles of TC degradation. This work provides a reference for designing efficient catalysts that can be combined with metal sulfides and biochar for efficient PMS activation.

Exploiting Co-C interface and graphitic carbon belts for enhanced structural stability of a porous layered Co-C catalyst for CO2 hydrogenation

Addressing the urgent need for efficient CO2 reduction, a novel Co@C catalyst was synthesized through the pyrolysis of a unique layered metal–organic framework (MOF), featuring tunable thickness, pore sizes. The CO2 hydrogenation performance demonstrates an enhancement by an optimized structure that significantly improves stability, maintaining a 25% CO2 conversion rate over an extended 80-hour period. The catalyst's composite structure exhibits a dual-confinement effect, where the Co-C interface and graphitic carbon belt stabilize Co nanoparticles, preventing sintering during reaction cycles. This study delves into the structural modifications necessary for catalytic optimization in CO2 hydrogenation, offering valuable insights for designing efficient catalysts for CO2 reduction and advancing sustainable energy solutions.

Nanoporous NiPt alloy by dealloying of amorphous NiZrPt metallic glass for alkaline hydrogen evolution reaction

The development of high-performance and low-cost alkaline hydrogen precipitation catalysts is critical for the large-scale application of hydrogen energy. In this work, the nanoporous alloy catalysts were synthesized by dealloying melt-spun NiZrPt ribbons. The optimal sample after dealloying shows excellent HER performance in alkaline medium, with a small overpotential of 15 mV to deliver 10 mA cm−2 and a low Tafel slope of 20 mV/dec. The material characterization reveals that the incorporation of Ni modulates the electronic structure of Pt. After selective dealloying of Zr and Ni, a Pt-enriched nanoporous structure was formed on the catalyst surface. Meanwhile, the remaining Ni sites acted as synergistic sites to activate the Pt sites, which allowed for better hydrogen adsorption energy and faster kinetics of the catalytic reaction. Besides, the favorable mechanical flexibility of the material makes it potential for self-supporting electrode. This work presents a way to prepare low-Pt efficient catalysts by amorphous alloy dealloying.

Nickel Foam-Loaded Zn/Co Bimetallic Phosphide as an Efficient Bifunctional Electrolytic Water Catalyst

Nickel Foam-Loaded Zn/Co Bimetallic Phosphide as an Efficient Bifunctional Electrolytic Water Catalyst

Efficient Hydrogen Production over Molybdenum Tungsten Bimetallic Oxide NF/PMonW12-n Catalyst on Nickel Foam.

Developing inexpensive, efficient, and stable catalysts is crucial for reducing the cost of electrolytic hydrogen production. Recently, polyoxometalates (POMs) have gained attention and widespread use due to their excellent electrocatalytic properties. This study designed and synthesized three composite materials, NF/PMonW12-n, by using phosphomolybdic-tungstic heteropolyacids as precursors to grow in situ on nickel foam via the hydrothermal process and subsequent calcination. Then, their catalytic performances are systematically investigated. This work demonstrates that the NF/PMonW12-n catalysts generate more low valent oxides under the synergistic effect of Mo and W, further enhancing activity for hydrogen evolution reaction (HER). Among these electrocatalysts, NF/PMo6W6 exhibits the perfect HER performance, η10 is only 74 mV. It also shows great stability during long-term electrolysis. The current study introduces a fresh approach for producing electrocatalysts that are both cost-effective and highly efficient.

Kanamycin‐Cu(II) Complex Catalyzed Ullmann Amine Synthesis at Room Temperature: A Tool for Mechanistic Insights into Methylene Blue Degradation

This study highlights the significance of Ullmann coupling reaction in modern organic synthesis and advances catalytic methodologies through the introduction of a kanamycin‐copper complex as a highly efficient catalyst for the synthesis of diverse N‐Aryl compounds. We demonstrate the catalyst's versatility through the synthesis of 20 Daryl‐amine instances, 21 Ar(het)‐N compounds, and 10 miscellaneous examples. NMR, IR, and UV spectroscopy offers insights into the catalyst's behaviour. Additionally, DFT studies support the catalyst's proficiency in generating SO4 radicals by stabilizing with aminosugars moieties. Ex‐situ NMR experiments confirm a ternary complex‐based mechanism at concentrations below 0.1μM. Furthermore, we showcase the degradation of methylene blue to its precursor amine under optimized conditions. Overall, this research underscores the potential of Ullmann condensation reactions in contemporary organic synthesis and contributes significantly to the advancement of catalytic methodologies.

Coordination-induced amidated modified polyacrylonitrile loaded ultrafine palladium nanoparticles for thermocatalytic hydrogen evolution

A promising approach for powering hydrogen fuel cells (HFCs) involves the in-situ production of hydrogen from formic acid decomposition, with Pd-based catalysts recognized as effective for formic acid dehydrogenation. However, the immobilization of ultrafine palladium nanoparticles (Pd NPs) on catalytic supports presents a challenge and necessitates further investigation into their formation mechanism. We propose a coordination-induced strategy to understand the behavior of ultrafine Pd NPs formation based on multi-functional groups. To establish the structure–activity relationship for tunable Pd microenvironment and catalytic performance, we synthesized various polyacrylonitrile (PAN) carriers through hydrolysis and amidation modification. Molecular dynamics simulations confirmed that a stronger coordination-induced microenvironment facilitates the dispersion of Pd2+, suppressing aggregation and enhancing Pd loading. Our experimental results and density functional theory (DFT) calculations demonstrated that the catalytic activity of Pd@APAN(15_1%) with ultrafine Pd NPs (1.5 nm) exhibits over 10 times higher than that of Pd@PAN NPs with the turnover of frequency climbing from 112.6 h−1 to 1309.4 h−1 at 323 K. And Pd-imine and Pd-secondary amine moieties were verified to contribute to the creation of a favorable catalysis microenvironment. This study provides new insights into the design of modified supports with various groups to load well-dispersed and ultrafine Pd for highly efficient catalysts based on a coordination-induced strategy.

Lattice Oxygen Activation through Deep Oxidation of Co4N by Jahn-Teller-active Dopants for Improved Electrocatalytic Oxygen Evolution.

Triggering the lattice oxygen oxidation mechanism is crucial for improving oxygen evolution reaction (OER) performance, because it could bypass the scaling relation limitation associated with the conventional adsorbate evolution mechanism through the directly formation of oxygen-oxygen bond. High-valence transition metal sites are favorable for activating the lattice oxygen, but the deep oxidation of pre-catalysts suffers from a high thermodynamic barrier. Here, taking advantage of the Jahn-Teller (J-T) distortion induced structural instability, we incorporate high-spin Mn3+ (t2g3eg1) dopant into Co4N. Mn dopants enable a surface structural transformation from Co4N to CoOOH, and finally to CoO2, as observed by various in-situ spectroscopic investigations. Furthermore, the reconstructed surface on Mn doped Co4N triggers the lattice oxygen activation, as evidenced experimentally by pH-dependent OER, tetramethylammonium cation adsorption and on-line electrochemical mass spectrometry measurements of 18O-labelled catalysts. In general, this work not only offers the introducing J-T effect approach to regulate the structural transition, but also provides an understanding about the influence of catalyst's electronic configuration on determining the reaction route, which may inspire the design of more efficient catalysts with activated lattice oxygen.

Hollow g-C3N4@Ag3PO4 Core-Shell Nanoreactor Loaded with Au Nanoparticles: Boosting Photothermal Catalysis in Confined Space.

Low solar energy utilization efficiency and serious charge recombination remain major challenges for photocatalytic systems. Herein, a hollow core-shell Au/g-C3N4@Ag3PO4 photothermal nanoreactor is successfully prepared by a two-step deposition method. Benefit from efficient spectral utilization and fast charge separation induced by the unique hollow core-shell heterostructure, the H2 evolution rate of Au/g-C3N4@Ag3PO4 is 16.9 times that of the pristine g-C3N4, and the degradation efficiency of tetracycline is increased by 88.1%. The enhanced catalytic performance can be attributed to the ordered charge movement on the hollow core-shell structure and a local high-temperature environment, which effectively accelerates the carrier separation and chemical reaction kinetics. This work highlights the important role of the space confinement effect in photothermal catalysis and provides a promising strategy for the development of the next generation of highly efficient photothermal catalysts.

Cobalt Phosphide-Supported Single-Atom Pt Catalysts for Efficient and Stable Hydrogen Generation from Ammonia Borane Hydrolysis.

Ammonia borane (AB) has emerged as a promising chemical hydrogen storage material. The development of efficient, stable, and cost-effective catalysts for AB hydrolysis is the key to achieving hydrogen energy economy. Here, cobalt phosphide (CoP) is used to anchor single-atom Pt species, acting as robust catalysts for hydrogen generation from AB hydrolysis. Thanks to the high Pt utilization and the synergy between CoP and Pt species, the optimized Pt/CoP-100 catalyst exhibits an unprecedented hydrogen generation rate, giving a record turnover frequency (TOF) value of 39911 and turnover number of 2926829 at room temperature. These metrics surpass those of all existing state-of-the-art supported metal catalysts by an order of magnitude. Density functional theory calculations reveal that the integration of single-atom Pt onto the CoP substrate significantly enhances adsorption and dissociation processes for both water and AB molecules, thereby facilitating hydrogen production from AB hydrolysis. Interestingly, the TOF value is further elevated to 54878 under UV-vis light irradiation, which can be attributed to the efficient separation and mobility of photogenerated carriers at the Pt-CoP interface. The findings underscore the effectiveness of CoP as a support for single-atom metals in hydrogen production, offering insights for designing high-performance catalysts for chemical hydrogen storage.

Metal Ion and Metal‐to‐Ligand Ratio Regulated Construction of Cu(II) and Co(II) Coordination Polymers as Efficient Catalysts for Ring‐Opening Polymerization of L‐Lactide

AbstractThree new coordination polymers (CPs), {[Cu(NDC)(Fbtx)(H2O)] ⋅ 1.5H2O}n (1), {[Co(NDC)(Fbtx)(H2O)2] ⋅ 0.5Fbtx}n (2), and [Co2(NDC)2(Fbtx)]n (3), were synthesized by employing acid‐base mixed ligands of rigid 1,4‐naphthalenedicarboxylic acid (H2NDC) and flexible bis(1,2,4‐triazole‐1‐ylmethyl)‐2,3,5,6‐tetrafluorobenzene (Fbtx) under both hydrothermal and microwave‐assisted reaction conditions. Single‐crystal structure analysis establishted that both compounds 1 and 2 exhibit two‐dimensional (2D) layered structures, while compound 3 features a three‐dimensional (3D) complicated framework. The geometries of metal ions vary from square pyramidal (in 1 and 3) to distorted octahedral (in 2). Topological strudy showed that compounds 1 and 2 have exposed common 4‐connected 44‐sql net, while compound 3 has made a novel 4,5‐connected net with point symbol of (43 ⋅ 62 ⋅ 7)(43 ⋅ 64 ⋅ 72 ⋅ 8). The catalytic performance of the three complexes for the solvent‐free ring‐opening polymerization of L‐lactide has been investigated. The results indicated that compound 3 with coordinatively unsaturated cobalt(II) sites showed good activity and the molecular weight of the polymer obtained was high. Moreover, the complex 3 catalyst could be recycled up to five times with the retention of both catalytic activity and crystal structure.

Photoelectrocatalytic Synthesis of Urea from Carbon Dioxide and Nitrate over a Cu2O Photocathode

Transformation of carbon dioxide and nitrate ions into urea offers an attractive route for both nitrogen fertilizer production and environmental remediation. However, achieving this transformation under mild conditions remains challenging. Herein, we report an efficient photoelectrochemical method for urea synthesis by co‐reduction of carbon dioxide and nitrate ion over a Cu2O photocathode, delivering urea formation rate of 29.71±2.20 μmol g−1 h−1 and Faradaic efficiency (FE) of 12.90±1.15 % at low external potential (−0.017 V vs. reversible hydrogen electrode). Experimental data combined with theoretical calculations suggest that the adsorbed CO* and NO2* species are the key intermediates, and associated C−N coupling is the rate‐determining step. This work demonstrates that Cu2O is an efficient catalyst to drive co‐reduction of CO2 and NO3− to urea under light irradiation with low external potential, showing great opportunity of photoelectrocatalysis as a sustainable tool for value‐added chemical synthesis.

Photoelectrocatalytic Synthesis of Urea from Carbon Dioxide and Nitrate over a Cu2O Photocathode.

Transformation of carbon dioxide and nitrate ions into urea offers an attractive route for both nitrogen fertilizer production and environmental remediation. However, achieving this transformation under mild conditions remains challenging. Herein, we report an efficient photoelectrochemical method for urea synthesis by co-reduction of carbon dioxide and nitrate ion over a Cu2O photocathode, delivering urea formation rate of 29.71±2.20 μmol g-1 h-1 and Faradaic efficiency (FE) of 12.90±1.15 % at low external potential (-0.017 V vs. reversible hydrogen electrode). Experimental data combined with theoretical calculations suggest that the adsorbed CO* and NO2* species are the key intermediates, and associated C-N coupling is the rate-determining step. This work demonstrates that Cu2O is an efficient catalyst to drive co-reduction of CO2 and NO3- to urea under light irradiation with low external potential, showing great opportunity of photoelectrocatalysis as a sustainable tool for value-added chemical synthesis.

Sub-2.5 nm monodisperse Mo2C nanoparticles on N-doped carbon: The facet engineering for boosting electrochemical hydrogen evolution

Molybdenum carbide materials have demonstrated remarkable potential in catalyzing the hydrogen evolution reaction (HER). However, further modulation of their performance through simultaneously engineering the size and surface crystal facets remains challenging. Herein, we report the successful fabrication of N-doped carbon-supported monodisperse Mo2C nanoparticles with a size of ∼2.06 nm, exhibiting co-exposed (101)/(102) facets-heterojunction, derived from annealing glycine and ammonium molybdate tetrahydrate. The optimized Mo2C/NC-Amt catalyst exhibits a low overpotentials of 128 mV to achieve the current density of 10 mA cm−2 and a small Tafel slope of 72 mV dec−1 under alkaline solution. By changing the molybdate precursor, the phase and crystal facet composition of molybdenum carbide can be effectively tuned, which provides a good platform for studying their structure-activity in HER. The theoretical calculations reveal the synergistic effect of (101)/(102) facets-heterojunction accelerates electron transfer and regulates the d band center of Mo2C, reducing the reaction barriers of intermediates in the HER process, thus significantly boosting reaction activity. This work proposes a novel insight into the rational fabrication of efficient HER catalysts through facet engineering toward heterojunction construction under the 2.5 nm region.

3D printed textured substrate with ZnIn2S4–Pt–Co thermoset coating for photocatalytic hydrogen evolution

Immobilized efficient catalysts on 3D substrate structures are practical and effective for improving photocatalytic hydrogen production, yet the deposition of photocatalysts on the 3D substrate remains the challenging. In this work, ZnIn2S4 microspheres were synthesized with Pt–Co as cocatalysts (named as ZIS-Pt-Co) and firmly loaded as the thermoset coatings onto the 3D printed textured substrate. Two morphologies of 3D printed textured substrate, upright pyramid and inverted pyramid structure, were prepared by DLP to improve the specific surface area for hydrogen evolution. Under the optimal ZIS-Pt-Co coatings mass of approximately 12.6 mg, the inverted pyramid structure was found to have a better hydrogen production yields (1555 μmol h−1 g−1). By adequately utilizing the synergistic effect of the catalysts and the 3D printed substrates for photocatalytic hydrogen production, the photocatalytic water splitting performance was improved without using sacrificial agents. Moreover, the substrates can be reused multiple times with new catalysts coating for the photocatalytic reaction. This will be beneficial for promoting the application and promotion of low-cost, large-area photocatalytic reactors.