Heterogeneous Nanoparticle Catalysts Research Articles

High-Performance MoP-Mo2C/C Heterogeneous Nanoparticle Catalysts for Alkaline Hydrogen Evolution and Oxidation Reactions

High-Performance MoP-Mo₂C/C Heterogeneous Nanoparticle Catalysts for Alkaline Hydrogen Evolution and Oxidation Reactions

Nanoparticles for the synthesis of bio‐based chemical 5‐Hydroxymethyl furfural from agricultural waste and biomass‐derived carbohydrates‐A review

AbstractThe need for 5‐Hydroxymethylfurfural (HMF) has garnered significant attention owing to its versatile applications in the chemical industry as a precursor for biofuels, pharmaceuticals and fine chemicals. This abstract summarizes a complete review on the synthesis of HMF using heterogeneous catalyst from agriculture waste and various biomass‐derived carbohydrates, focusing on their efficiency, selectivity and industrial feasibility. This review systematically outlines the diverse classes of heterogeneous catalyst employed in HMF production, including titanium dioxide (TiO2), zirconium dioxide (ZrO2), silicon dioxide (SiO2) and aluminium oxide (Al2O3), where the discussion highlights their catalytic mechanisms and intrinsic properties that influence HMF yield, selectivity, stability and reusability. In addition, the impact of reaction parameters such as temperature, pressure, solvent, feedstock composition and catalyst morphology on HMF synthesis has been assessed. This review consolidates the current state‐of‐the‐art methodologies in the synthesis of HMF using various heterogeneous nanoparticle catalysts. © 2024 Society of Chemical Industry (SCI).

BaO as a heterogeneous nanoparticle catalyst in oil transesterification for the production of FAME fuel

Metal oxide-based catalysts play an important role in the transesterification reaction of vegetable oils for fatty acid methyl ester (FAME) production. Additionally, nanocatalysts demonstrate high efficiency due to their increased surface area, higher catalytic activity, and easy operational procedures. Thus, the main objective of this work is to investigate FAME production from sunflower oil using barium oxide (BaO) nanoparticles. BaO was synthesized through one-pot sol–gel reactions and was analysed by several techniques, such as X-ray diffraction (XRD), transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence(EDXRF), N2 adsorption–desorption of liquid nitrogen at 77 K [Brunner–Emmett–Teller (BET)] for surface area measurement and UV–Vis spectroscopy. BaO behaved as an efficient catalyst in the transesterification of oils into FAMEs. Furthermore, the impacts of a variety of reaction parameters on the biofuel yield were explored. The catalyst with 4.7 wt% has the maximum yield of 78.38 % achieved under the optimized reaction conditions (70 °C, 1:20 M ratio of oil:methanol). The characteristics of the resulting methyl ester partially agreed with international FAME standards, making it suitable for use as a blend with petroleum diesel in proportions defined by volume according to the specifications of the American Society for Testing and Materials(ASTM). The catalyst was also evaluated for reusability tests, and the reusability through the reaction showed less than a 7 % conversion drop after 3 runs and 14.6 % after 5 runs.

Aptamer-Modified Homogeneous Catalysts, Heterogenous Nanoparticle Catalysts, and Photocatalysts: Functional "Nucleoapzymes", "Aptananozymes", and "Photoaptazymes".

Conjugation of aptamers to homogeneous catalysts ("nucleoapzymes"), heterogeneous nanoparticle catalysts ("aptananozymes"), and photocatalysts ("photoaptazymes") yields superior catalytic/photocatalytic hybrid nanostructures emulating functions of native enzymes and photosystems. The concentration of the substrate in proximity to the catalytic sites ("molarity effect") or spatial concentration of electron-acceptor units in spatial proximity to the photosensitizers, by aptamer-ligand complexes, leads to enhanced catalytic/photocatalytic efficacies of the hybrid nanostructures. This is exemplified by sets of "nucleoapzymes" composed of aptamers conjugated to the hemin/G-quadruplex DNAzymes or metal-ligand complexes as catalysts, catalyzing the oxidation of dopamine to aminochrome, oxygen-insertion into the Ar─H moiety of tyrosinamide and the subsequent oxidation of the catechol product into aminochrome, or the hydrolysis of esters or ATP. Also, aptananozymes consisting of aptamers conjugated to Cu2+ - or Ce4+ -ion-modified C-dots or polyadenine-stabilized Au nanoparticles acting as catalysts oxidizingdopamine or operating bioreactor biocatalytic cascades, are demonstrated. In addition, aptamers conjugated to the Ru(II)-tris-bipyridine photosensitizer or the Zn(II) protoporphyrin IX photosensitizer provide supramolecular photoaptazyme assemblies emulating native photosynthetic reaction centers. Effective photoinduced electron transfer followed by the catalyzed synthesis of NADPH or the evolution of H2 is demonstrated by the photosystems. Structure-function relationships dictate the catalytic and photocatalytic efficacies of the systems.

Recent Development of Single-Atom Catalysis for the Functionalization of Alkenes

The functionalization of alkenes is one of the most important conversions in synthetic chemistry to prepare numerous fine chemicals. Typical procedures, such as hydrosilylation and hydroformylation, are traditionally catalyzed using homogeneous noble metal complexes, while the highly reactive and stable heterogeneous single-atom catalysts (SACs) now provide alternative approaches to fulfill these conversions by combining the advantages of both homogeneous catalysts and heterogeneous nanoparticle catalysts. In this review, the recent achievement in single-atom catalyzed hydrosilylation and hydroformylation reactions are introduced, and we highlight the latest applications of SACs for additive reactions, constructing new C-Y (Y = B, P, S, N) bonds on the terminal carbon atoms of alkenes, and then mention the applications in single-metal-atom catalyzed hydrogenation and epoxidation reactions. We also note that some tandem reactions are conveniently realized in one pot by the concisely fabricated SACs, facilitating the preparation of some pharmaceutical compounds. Lastly, the challenges facing single-atom catalysis for alkene conversions are briefly mentioned.

Selective mono-N-methylation of amines using methanol as a methylating reagent over heterogeneous Ni catalysts

Mixed oxide (ZnAlOx) supported heterogeneous Ni nanoparticle catalysts (Ni/ZnAlOx-600) for the direct synthesis of mono-N-methylamines from amines and methanol.

Soluble porous organic cages as homogenizers and electron-acceptors for homogenization of heterogeneous alloy nanoparticle catalysts with enhanced catalytic activity

The creation of ultrafine alloy nanoparticles (<5 nm) that can maintain surface activity and avoid aggregation for heterogeneous catalysis has received much attention and is extremely challenging. Here, ultrafine PtRh alloy nanoparticles imprisoned by the cavities of reduced chiral covalent imine cage (PtRh@RCC3) are prepared successfully by an organic molecular cage (OMC) confinement strategy, while the soluble RCC3 can act as a homogenizer to homogenize the heterogeneous PtRh alloy in solution. Moreover, the X-ray absorption near-edge structure (XANES) results show that the RCC3 can act as an electron-acceptor to withdraw electrons from Pt, leading to the formation of higher valence Pt atoms, which is beneficial to improving the catalytic activity for the reduction of 4-nitrophenol. Attributed to the synergistic effect of Pt/Rh atoms and the unique function of the RCC3, the reaction rate constants of Pt1Rh16@RCC3 are 49.6, 8.2, and 5.5 times than those of the Pt1Rh16 bulk, Pt@RCC3 and Rh@RCC3, respectively. This work provides a feasible strategy to homogenize heterogeneous alloy nanoparticle catalysts in solution, showing huge potential for advanced catalytic application.

Surface Valence State Effect of MoO2+x on Electrochemical Nitrogen Reduction.

The valance of Mo is critical for FeMo cofactor in ambient ammonia synthesis. However, the valence effect of Mo has not been well studied in heterogeneous nanoparticle catalysts for electrochemical nitrogen reduction reaction (NRR) due to the dissolution of Mo as MoO4 2− in alkaline electrolytes. Here, a MoO2+ x catalyst enriched with surface Mo6+ is reported. The Mo6+ is stabilized by a native oxide layer to prevent corrosion and its speciation is identified as (MoO3) n clusters. This native layer with Mo6+ suppresses the hydrogen evolution significantly and promotes the activation of nitrogen as supported by both experimental characterization and theoretical calculation. The as‐prepared MoO2+ x catalyst shows a high ammonia yield of 3.95 µg mgcat −1h−1 with a high Faradaic efficiency of 22.1% at −0.2 V versus reversible hydrogen electrode, which is much better than the MoO2 catalyst with Mo6+ etched away. The accuracy of experimental results for NRR is confirmed by various control experiments and quantitative isotope labeling.

Fe3O4@SiO2-Propyl Covalent Dapsone-Copper Complex: Synthesis, Characterization and Application for the Synthesis of New Derivatives of Azo-Linked Thiazolidinones and their Solvatochromism Evaluation

Background: Thiazolidinone-4-ones belong to an important heterocyclic compounds because of their broad spectrum of biological activities. Several methods for the synthesis of 4-thiazolidinones were reported in the literature. The main synthetic routes to synthesize 1,3-thiazolidin-4-ones is the three component reaction between amine, a carbonyl compound and a mercapto-acid. Objective: Dapsone-Cu supported on silica coated Fe3O4 (Fe3O4@SiO2-pr@dapsone-Cu) as a new heterogeneous nanoparticle catalyst was synthesized and the structure and morphology of this catalyst were characterized by Fourier transform infrared spectroscopy (FT-IR), Xray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), zeta potential, vibrating sample magnetometry (VSM) and thermal gravimetric analysis (TGA). The new synthesized catalyst was applied as an effective nanocatalyst for the synthesis of new derivatives of azo-linked thiazolidinones through one-pot multi-component reaction of various aromatic aldehydes, thioglycolic acid and 4-aminoazobenzene under solvent-free condition. Methods: A mixture of aldehyde, thioglycolic acid, 4-aminoazobenzene (1 mmol) and 0.05 g Fe3O4@SiO2@dapsone-Cu MNPs were stirred at room temperature under solvent-free condition. Results: We report a facile, green, new and efficient method for the synthesis of thiazolidine-4-ones through three component reaction of various aldehydes, thioglycolic acid and 4-aminoazobenzene in the presence of Fe3O4@SiO2-propyl@dapsone-Cu complex under solvent-free reaction. Conclusion: This new procedure has the notable advantages such as excellent yields, short reaction time, operational simplicity, easy work-up, eco-friendly and using a non-toxic catalyst. Also, the catalyst is easily recoverable in the presence of an enourmous magnet and reused for six consecutive reaction cycles without significant loss of activity.

Aerobic oxidation of alcohols enabled by nitrogen-doped copper nanoparticle catalysts

Heterogeneous nitrogen-doped carbon-incarcerated copper nanoparticle catalysts have been developed.

Porous organic polymer immobilized copper nanoparticles as heterogeneous catalyst for efficient benzylic C–H bond oxidation

A facile and practical heterogeneous copper nanoparticles catalyst (Cu@AEPOP) was prepared by the incorporation of Cu(OAc)2 to amide and ether functionalized porous organic polymers (AEPOP) that were efficiently prepared by condensation of 4,4′-diaminodiphenyl ether with 1,3,5-benzenetricarbonyl chloride. The prepared AEPOP and Cu@AEPOP were characterized by SEM, BET, TEM, ICP, FT-IR and XRD. With TBHP (70 wt% in water) as oxidant and solvent, Cu@AEPOP showed excellent catalytic activity for the selective oxidation of benzylic C–H bonds. Among the oxidation of alkyl benzenes to ketones, secondary alcohols to ketones, and primary alcohols to acids, the copper catalyst exhibited remarkable selectivity and reactivity for a broad range of substrates in excellent yields. Furthermore, the experimental operation was very facile and the heterogeneous catalyst could be easily recovered by filtration separation.

Development of Trifluoromethanesulfonic Acid-Immobilized Nitrogen-Doped Carbon-Incarcerated Niobia Nanoparticle Catalysts for Friedel-Crafts Acylation.

Heterogeneous trifluoromethanesulfonic acid-immobilized nitrogen-doped carbon-incarcerated niobia nanoparticle catalysts (NCI-Nb-TfOH) that show excellent catalytic performance with low niobium loading (1 mol %) in Friedel-Crafts acylation have been developed. These catalysts exhibit higher activity and higher tolerance to catalytic poisons compared with the previously reported TfOH-treated NCI-Ti catalysts, leading to a broader substrate scope. The catalysts were characterized via spectroscopic and microscopic studies.

Enantioselective Addition of Dialkylzinc to Aldehydes on a Heterogeneous Magnetic Nanoparticle Catalyst

Enantioselective Addition of Dialkylzinc to Aldehydes on a Heterogeneous Magnetic Nanoparticle Catalyst

Transesterification Reaction from Rice Bran Oil to Biodiesel over Heterogeneous Base Calcium Oxide Nanoparticles Catalyst

This research focused on the use of heterogeneous base catalyst, calcium oxide (CaO), an alkaline earth metal oxide to produce biodiesel. The aim of this research is to investigate the potential of commercial calcium carbonate, CM-CaCO3 to be transformed to nanostructured CaO and further used as a heterogeneous base catalyst for single step transesterification of rice bran oil to biodiesel. The CaO samples were calcined at temperatures of 100°C to 700°C under vacuum at 10-3 mbar. TGA-DTA result displayed that the calcination temperature for CM-CaCO3 to form CaO must be higher than 600°C. This was supported by FTIR results which indicated the complete formation of CaO at 700°C. XRD showed the rhombohedral CaCO3 and hexagonal Ca(OH)2 were totally disappeared, leaving only crystalline cubic CaO at 700oC. Interestingly, CaO obtained at 700°C (CaO-700) showed the larger BET surface area and highest basicity with 11.5 m2g-1 and 1.959 mmol/g, respectively. The prepared nanostructured CaO-700 was selected and applied for single step transesterification reaction of rice bran oil to produce biodiesel. NMR and GC-FID results further confirmed that biodiesel was successfully formed using CaO-700 as catalyst.

Towards high-performance heterogeneous palladium nanoparticle catalysts for sustainable liquid-phase reactions

A walk-through of nanoparticle–reactant/product, nanoparticle–support and support–reactant/product interaction effects on the catalytic performance of heterogeneous palladium catalysts in liquid-phase reactions.

Water Oxidation Catalysts for Artificial Photosynthesis

Water oxidation is the primary reaction of both natural and artificial photosynthesis. Developing active and robust water oxidation catalysts (WOCs) is the key to constructing efficient artificial photosynthesis systems, but it is still facing enormous challenges in both fundamental and applied aspects. Here, the recent developments in molecular catalysts and heterogeneous nanoparticle catalysts are reviewed with special emphasis on biomimetic catalysts and the integration of WOCs into artificial photosystems. The highly efficient artificial photosynthesis depends largely on active WOCs integrated into light harvesting materials via rational interface engineering based on in-depth understanding of charge dynamics and the reaction mechanism.

Hydrogen storage in formic acid as a renewable energy source using heterogeneous catalysis

One of the most vital chemicals, which is not only found naturally but can also be synthesized in the laboratory, is formic acid (FA). FA is a key byproduct of several second-generation biorefinery processes as well, and it is used in several pharmaceutical and industrial applications. Recently, another significant use of FA that is taking the lead is as a form of fuel. This could either involve reformation, as a possible form of chemical hydrogen storage, or be done without reformation in the form of FA fuel cells, in particular because FA fuel cells are much more effective than other proton-exchange membrane fuel cells. Therefore, FA is a highly useful fuel for applications such as vehicles and portable devices. This review is based on recent developments and processes, showing that FA should become a prominent reversible source for hydrogen storage. Recent developments should permit a cheap and extremely effective source of rechargeable hydrogen fuel cells in the future. This will be possible through the usage of appropriate heterogeneous metal nanoparticle catalysts under ideal reaction conditions. The most significant aspect will be the usage of atmospheric CO$_{2}$, which is a greenhouse gas, to develop FA, as that would help to reduce the quantity of CO$_{2}$ in the atmosphere and diminish global warming.

Continuous Production of Hydrogen from Formic Acid Decomposition Over Heterogeneous Nanoparticle Catalysts: From Batch to Continuous Flow

We investigate the continuous generation of hy-drogen via the low temperature (< 110 °C), additive-free dehydrogenation of formic acid over heterogeneous Pd/C. Through a combination of kinetic (batch and continuous), spectroscopic and mechanistic studies, we develop structure-activity-lifetime relationships for this process, and in doing so reveal that a combination of pore fouling and poisoning by formate ions result in deactivation of the catalyst during continuous operation. Although these factors result in extensive deactivation in Plug Flow mode, promising results can be obtained by minimizing the steady state concentration of formic acid by operating in a Continuous Stirred Tank reactor. In doing so, continuous operation of the system without loss of activity for over 2500 turnovers is achieved, at mild conditions and in the absence of stoichiometric additives.

Sensing and photocatalytic properties of nanosized Cu(I)CN organotin supramolecular coordination polymer based on pyrazine

Orange prismatic crystals of the supramolecular coordination polymer (SCP) ∞3[Cu(CN)2(Me3Sn)(Pyz)], SCP1, were synthesized using a self‐assembly method under ambient conditions. Nanosized 1 was obtained using the same molar ratio in water by ultrasonic irradiation. SCP1 was characterized using single‐crystal X‐ray diffraction, elemental analysis, thermal analysis and Fourier transform infrared spectroscopy. SCP1 and its nanosized 1 particles were also examined using powder X‐ay diffraction and scanning electron microscopy. The luminescence emission of SCP1 was studied as well as its use as a sensor for the detection of common organic solvents and metal ions. Also, the catalytic activities of nanosized 1 towards various organic dyes were investigated under ambient conditions, UV irradiation and ultrasonic irradiation. Nanosized 1 as a heterogeneous nanoparticle catalyst exhibits high catalytic activity for the degradation of eosin‐Y and acid blue dyes. The mechanism of degradation investigated using various scavenger techniques is proposed and discussed. The catalytic oxidation process is mainly caused by •OH radicals.

Synergistic catalysis of Cu+/Cu0 for efficient and selective N-methylation of nitroarenes with para-formaldehyde

In this paper, an inexpensive heterogeneous copper nanoparticles catalyst derived from CuAl-layered double hydroxide via an in situ topotactic transformation process was developed. Cu nanoparticles with uniform size were homogeneously dispersed on amorphous Al2O3 with strong metal-support interaction. Characterization results reveals that the Cu0 and Cu+ were simultaneously formed with Cu+ species as the dominant sites on the surface during the reduction process. The resultant catalyst Cu/Al2O3 demonstrates high catalytic activity, selectivity and durability for the reductive N-methylation of easily available nitroarenes in a cost-efficient, environmentally friendly and cascade manner. A broad spectrum of nitroarenes could be efficiently N-methylated to their corresponding N,N-dimethyl amines with good compatibility of various functional groups. The protocol is also applicable for the late-stage functionalization of biologically and pharmaceutically active nitro molecules. A structure-function relationship discloses that Cu0 and Cu+ sites on the surface pronouncedly boosts the reaction efficiency in a synergistic manner, in which Cu0 could facilitate H2 production and N-methylation of anilines, while Cu+ is considerably more active and participates in the overall process of the selective N-methylation of nitroarenes. Moreover, the catalyst also showed a strong stability and could be easily separated for successive reuses without an appreciable loss in activity and selectivity.