A COF template-derived mesoporous CeO2-supported Au nanoparticles catalyst for the oxidative esterification of benzaldehydes and benzyl alcohols.

The direct oxidative esterification of benzaldehydes and benzyl alcohols to high value-added aromatic esters under mild and green reaction conditions is significant in the fine chemical industry. The accurate design of catalysts with high catalytic performance is crucial for this process. Herein, 2,4,6-trimethylpyridine, benzoic anhydride, and terephthalaldehyde were used to prepare a covalent organic framework (COF) material, which was then used as a template to construct a mesoporous CeO2-supported Au nanoparticles catalyst. The obtained Au@CeO2 catalyst was thoroughly characterized, and it possessed a mesoporous structure with a high surface area. Meanwhile, the as-prepared Au@CeO2 exhibited excellent catalytic performance in the oxidative esterification of benzaldehydes and benzyl alcohols with methanol, affording the corresponding aromatic esters under mild and green reaction conditions. Furthermore, the Au@CeO2 catalyst could also be recycled. Therefore, this study provides a green and sustainable pathway for the synthesis of high-value-added esters through a direct oxidative esterification strategy.

Preparation of mesoporous chitosan iron supported nano-catalyst for the catalyzed oxidation of primary amine to imine.

Supported nano-catalysts with environmental sustainability and high catalytic performance are of great research interest for sustainable catalysis. In this article, a supported nano-catalyst, FeA-NC, with high catalytic performance was prepared by anchoring the transition metal iron onto nitrogen-doped porous carbon materials using chitosan as a raw material. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) measurement results demonstrated that the obtained catalyst has an excellent mesoporous structure, and that the element Fe is evenly distributed. The support contains abundant N atoms, which can provide sufficient anchoring points for Fe and form Fe-Nx groups with Fe, improving the catalytic activity of the catalyst. Additionally, the FeA-NC with a porous structure can also enhance the mass transfer of reactants to improve the reaction efficiency. In addition, the prepared catalyst was used to catalyze the conversion of primary amines to the corresponding imines. The results showed that the direct oxidation of primary amines to the corresponding imines can be catalyzed by using air as an oxygen source and distilled H2O as a solvent under atmospheric pressure at 90 °C. Finally, the selectivity and stability of the as-prepared catalyst were also verified.

Mesoporous α-Al2O3-supported PdCu bimetallic nanoparticle catalyst for the selective semi-hydrogenation of alkynes.

The selective hydrogenation of alkynes to alkenes is widely applied in the chemical industry; nevertheless, achieving highly selective hydrogenation with high catalytic activity is considerably challenging. Herein, ultrafine PdCu bimetallic nanoparticles encapsulated by high-surface-area mesoporous α-Al2O3 were prepared by high-temperature calcination-reduction using a porous organic framework (POF) as the template. As-obtained PdCu@α-Al2O3 exhibited a high selectivity of 95% for the semi-hydrogenation of phenylacetylene as a probe reaction under mild reaction conditions. The separation of continuous Pd atoms and modification of the Pd electronic state by Cu atoms suppressed ß-hydride formation and alkene adsorption, contributing to high selectivity for the catalytic hydrogenation of alkynes. The catalytic activity was maintained after 7 cycles due to the strong interaction between the PdCu bimetallic nanoparticles and α-Al2O3 as well as the encapsulation effect of mesoporous α-Al2O3. Thus, the current work provides a facile strategy for fabricating high-surface-area mesoporous α-Al2O3-supported catalysts for industrial catalysis applications.

Preparation of core-shell catalyst for the tandem reaction of amino compounds with aldehydes.

Heterogeneous noble metal-based catalysts with stable, precise structures and high catalytic performance are of great research interest for sustainable catalysis. In this article, we designed a novel core-shell catalyst, Pd@UiO-66-NH2@mSiO2, with Pd@UiO-66-NH2 as the core and mesoporous SiO2 (mSiO2) as the shell. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) measurement results demonstrated that the obtained catalyst has an excellent core-shell structure. It can significantly prevent the aggregation of Pd nanoparticles (NPs), as well as the leaching of Pd NPs during the reaction process, owing to the protective effect of mSiO2. During the tandem reaction of aniline and benzaldehyde to generate secondary amines, the prepared Pd@UiO-66-NH2@mSiO2 is highly efficient, due to the strong acid sites provided by UiO-66-NH2 and the hydrogenation reduction sites provided by Pd NPs. Meanwhile, the Pd@UiO-66-NH2@mSiO2 with porous structure can also enhance the mass transfer of reactants to improve the reaction efficiency. Additionally, the prepared catalyst was used to catalyze the series reaction of amino compounds and aldehydes, and the results showed that just 5 mg of the catalyst can convert more than 99% of the reactants within 60 minutes in the presence of 1 atm H2 at room temperature. Finally, the selectivity and stability of the as-prepared catalyst were also confirmed.

Acceleration of the semi-hydrogenation of alkynes over an N-doped porous carbon sphere-confined ultrafine PdCu bimetallic nanoparticle catalyst.

Selective hydrogenation of alkynes to obtain alkenes is a key reaction in petrochemical and fine chemical industries. However, the development of stable and highly selective catalysts with uniformly dispersed active sites is still immensely challenging for the semi-hydrogenation of alkynes. In this study, N-doped porous carbon nanospheres (NPCNs) were synthesized by the nanoemulsion self-assembly and subsequently carbonization method. Ultrafine PdCu bimetallic nanoparticles (NPs) were uniformly dispersed and immobilized on NPCNs. The obtained PdCu/NPCNs catalyst exhibited an open framework and abundant active sites originating from ultrafine PdCu NPs. In the semi-hydrogenation of alkynes, the PdCu/NPCNs catalyst exhibited a remarkable performance and stability, outperforming most of the classical catalysts. The excellent performance was related to the introduction of a secondary metal Cu, which can regulate the electronic state of Pd active sites to further enhance the hydrogenation activity and selectivity. Hence, the facile approach reported herein may be useful for constructing highly dispersed bimetallic NP-based catalysts for selective hydrogenation of alkynes in the petrochemical industry.

Combining surface chemical functionalization with introducing reactive oxygen species boosts ethanol electrooxidation.

The introduction of functional groups or oxygen vacancies into Pd-based electrocatalysts is a powerful strategy for enhancing the electrocatalytic performances for many electrocatalytic reactions. Herein, an amorphous ceria-modified Pd nanocomposite anchored on D-4-amino-phenylalanine (DAP)-functionalized graphene nanosheets (Pd-CeO2-x/FGS) was prepared by a facile and effective one-pot synthetic strategy and further used as an electrocatalyst for the ethanol oxidation reaction (EOR) in alkaline electrolytes. The obtained Pd-CeO2-x/FGS exhibits relatively high electrocatalytic activity, fast kinetics and excellent antipoisoning ability as well as robust durability for EOR, outperforming the comparable electrocatalysts as well as commercial Pd/C. The experimental results show that the enhanced EOR properties of Pd-CeO2-x/FGS can be attributed to the DAP-functionalization and CeO2-x-modification. Adequate functional groups (amino and carboxyl groups) and abundant oxygen vacancies were introduced in Pd-CeO2-x/FGS by DAP-functionalization and CeO2-x-modification. The functional groups facilitate the anchoring of small nanoparticles onto the substrate as well as modulate the electron density of Pd. The oxygen vacancies boost the adsorption ability of the reactive oxygen species (OHads) and accelerate the kinetics of the potential-limiting step for EOR. This study proposes a new strategy for the rational design of highly efficient catalysts for the electro-oxidation reaction.

Ultrafine PdCo bimetallic nanoclusters confined in N-doped porous carbon for the efficient semi-hydrogenation of alkynes.

Semi-hydrogenation of alkynes to prepare alkenes is an important reaction in the petrochemical and fine chemical industries. The use of conventional Pd nanoparticle-based catalysts is limited by alkyne over-hydrogenation and low Pd utilization. In this study, a nitrogen-doped mesoporous carbon material (m-NC), which was rich in defect sites after Zn volatilization, was fabricated by the carbonization of ZIF-8. Ultrafine PdCo bimetallic nanoclusters with Co atom-modified Pd active site electronic and compositional structure were highly dispersed and confined in m-NC. As-obtained Pd0.43Co1/m-NC was used for the semi-hydrogenation of alkynes and it exhibited high selectivity with high conversion under mild reaction conditions. Pd0.43Co1/m-NC also exhibited excellent stability in leaching tests and maintained its catalytic activity for at least nine reaction cycles. The highly dispersed active sites in Pd0.43Co1/m-NC served as the active sites for the catalytic semi-hydrogenation of alkynes; as a regulator, the second metal Co effectively improved selectivity, and m-NC endowed the catalyst with excellent stability. The research work presented here may provide a foundation for the design of highly active, selective, and stable Pd-based bimetallic catalysts for selective hydrogenation.

Platinum clusters anchored on sulfur-doped ordered mesoporous carbon for chemoselective hydrogenation of halogenated nitroarenes.

Chemoselective hydrogenation of unsaturated organic compounds is a significant research topic in the catalysis field. Herein, a sulfur-doped ordered mesoporous carbon (SMC) material was prepared to anchor ultrafine platinum (Pt) clusters for the chemoselective hydrogenation of halogenated nitroarenes. The confinement effect of the ordered pores and the strong metal-support interaction caused by Pt clusters and sulfur atoms, efficiently suppress the aggregation and regulate the electronic states of the ultrafine Pt clusters. Thus, the hydrogenation of parachloronitrobenzene (p-CNB) shows high selectivity catalyzed by the ultrafine Pt clusters with electron-rich states. Meanwhile, the catalytic performance of the hydrogenation reaction catalyzed by Pt/SMC is capable of being maintained after at least 5 cycles, and the catalytic universality can also be applied to different halogenated nitroarenes hydrogenation. Therefore, this study may promote the research into the construction of noble metal-based catalysts for chemoselective hydrogenation reactions in green and sustainable chemical processes.

Ru nanoparticles anchored on porous N-doped carbon nanospheres for efficient catalytic hydrogenation of Levulinic acid to γ-valerolactone under solvent-free conditions.

The catalytic transformation of the biomass platform compound levulinic acid (LA) to γ-valerolactone (GVL) is a vital reaction to produce related renewable chemicals and fuels. Developing stable catalysts with highly dispersed and accessible ultrafine metal nanoparticle (NP) active sites for the hydrogenation of LA under solvent-free conditions is still a major challenge. Herein, a versatile nano-emulsion self-assembly method was employed to fabricate N-doped carbon nanospheres with a high specific surface area and hierarchically porous structure. Ultrafine Ru NPs were successfully anchored on the hierarchal porous N-doped carbon nanospheres (HPNC) with high dispersion. The obtained Ru/HPNC catalyst exhibited excellent catalytic performance for LA hydrogenation to GVL under solvent-free conditions with outstanding reusability. In contrast, Ru NPs embedded in other supports (including activated carbon and carbon nanotubes) were observed to be less effective under the same reaction conditions. The superior catalytic performance of the Ru/HPNC catalyst is due to the hierarchically porous catalyst structure, and accessible ultrafine Ru active sites which can promote the activation of CO bonds and H2 absorption during the catalytic process. The reaction pathway of LA hydrogenation to GVL is clearly researched by theoretical calculations. Thus, the current work provides a facile strategy for the synthesis of highly dispersed ultrafine metal NP-based catalysts for an important biomass transformation.

Facile preparation of ultrafine Pd nanoparticles anchored on covalent triazine frameworks catalysts for efficient N-alkylation.

The fabrication of stable and efficient catalysts for green and economic catalytic transformation is significant. Here, highly stable covalent triazine frameworks (CTF-1) were used as the supporting material for anchoring ultrafine Pd nanoparticles (NPs) via a facile impregnation process and a one-pot calcination-reduction strategy. The widespread dispersion of ultrafine Pd NPs was a result of the abundant high nitrogen-content triazine groups of CTF-1 that endowed the catalyst Pd@CTF-1 with high catalytic activity. The catalytic performance of Pd@CTF-1 was demonstrated by the one-pot N-alkylation of benzaldehyde with aniline (or nitrobenzene) under mild reaction conditions, and Pd@CTF-1 exhibited a wide range of general applicability for N-alkylation reactions. The reaction mechanism for the N-alkylation reaction was also studied in detail. In addition, the Pd@CTF-1 catalyst exhibited high thermal and chemical stability, maintaining good catalytic efficiency after multiple reaction cycles. This study provides new insights for the fabrication of organic supporting materials with highly dispersed active catalytic sites that can lead to excellent catalytic performance for efficient, economical, and green reactions.

Construction of a sandwich-like UiO-66-NH2@Pt@mSiO2 catalyst for one-pot cascade reductive amination of nitrobenzene with benzaldehyde.

Heterogeneous noble metal-based catalysts with stable, precise structures and high catalytic performance are of great research interest for sustainable catalysis. Herein, we designed the novel sandwich-like metal-organic-framework composite nanocatalyst UiO-66-NH2@Pt@mSiO2 using UiO-66-NH2@Pt as the core, and mesoporous SiO2 as the shell. The obtained UiO-66-NH2@Pt@mSiO2 catalyst shows a well-defined structure and interface, and the protection of the mSiO2 shell can efficiently prevent Pt NPs from aggregating and leaching in the reaction process. In the one-pot cascade reaction of nitroarenes and aromatic aldehydes to secondary amines, UiO-66-NH2@Pt@mSiO2 shows excellent catalytic performance due to acid catalytic sites provided by UiO-66-NH2 and Pt hydrogenation catalytic sites. Furthermore, the porous structure of the UiO-66-NH2@Pt@mSiO2 catalyst also enhances reactant diffusion and improves the reaction efficiency. This work provides a new avenue to meticulously design well-defined nanocatalysts with superior catalytic performance and stability for challenging reactions.

A Facile and In-situ Methanol-mediated Fabrication of Low Pd Loading, High-efficiency and Size-selectivity Pd@ZIF-8 Hydrogenation Catalyst.

In-situ encapsulation of tiny and well-dispersed Pd nanoparticles (Pd NPs) in zeolitic imidazolate frameworks (ZIFs) was firstly achieved using a one-pot and facile methanol-mediated growth approach, in which methanol served as both solvent and a mild reductant. The microstructure, morphology, crystallinity, porosity as well as evolution process of the catalysts were determined by TEM, XRD, N2 adsorption and UV-vis spectra. Due to the complete encapsulation of such Pd NPs combined with ultrahigh surface area and uniform microporous structure of ZIF-8, the resulting Pd@ZIF-8-60 min nanocomposite exhibited more superior catalytic activity for olefins hydrogenation with TOF of 7436 h-1 and excellent size selectivity than previously reported catalysts. Furthermore, the catalyst displays excellent recyclability for 1-octene hydrogenation and without any loss of the Pd active species.

Atomically Dispersed Co Clusters Anchored on N-doped Carbon Nanotubes for Efficient Dehydrogenation of Alcohols and Subsequent Conversion to Carboxylic Acids.

The catalytic dehydrogenation of readily available alcohols to high value-added carbonyl compounds is a research hotspot with scientific significance. Most of the current research about this reaction is performed with noble metal-based homogeneous catalysts of high price and poor reusability. Herein, highly dispersed Co-cluster-decorated N-doped carbon nanotubes (Co/N-CNTs) were fabricated via a facile strategy and used for the dehydrogenation of alcohols with high efficiency. Various characterization techniques confirmed the presence of metallic Co clusters with almost atomic dispersion, and the N-doped carbon supports also enhanced the catalytic activity of Co clusters in the dehydrogenation reaction. Aldehydes as dehydrogenation products were further transformed in situ to carboxylic acids through a Cannizzaro-type pathway under alkaline conditions. The reaction pathway of the dehydrogenation of alcohols was clearly confirmed by theoretical calculations. This work should provide an effective and simple approach for the accurate design and synthesis of small Co-clusters catalysts for the efficient dehydrogenation-based transformation of alcohols to carboxylic acids under mild reaction conditions.

Palladium Nanoclusters Confined in MOF@COP as a Novel Nanoreactor for Catalytic Hydrogenation.

Metal-nanocluster-doped porous materials are attracting considerable research attention due to their specific catalytic performance. In this study, core-shell metal-organic frameworks@covalent organic polymer (MOF@COP) nanocomposites were formed by the covalent linking of chemically stable COP on the surface of size-selective UiO-66-NH2. Pd nanoclusters with an average diameter of ∼0.8 nm were successfully confined in UiO-66-NH2@COP, and the obtained nanoreactor, referred to as UiO-66-NH2@COP@Pd, exhibited abundant porosity, high stability, and large surface area. Notably, the UiO-66-NH2@COP@Pd nanoreactor exhibited superior catalytic activity and stability for the catalytic reduction of 4-nitrophenol and hydrogenation of other nitroarenes, demonstrating the potential of Pd-cluster-doped MOF@COP hybrid materials as candidates for efficient catalytic hydrogenation. This study may provide new avenues for the construction of MOF@COP-hybrid-material-based heterogeneous catalysts for efficient catalytic applications.

Identification of a compound heterozygote in LYST gene: a case report on Chediak-Higashi syndrome.

BACKGROUND: Chediak-Higashi Syndrome (CHS) is a rare autosomal recessive disease caused by loss of function of the lysosomal trafficking regulator protein. The causative gene LYST/CHS1 was cloned and identified in 1996, which showed significant homology to other species such as bovine and mouse. To date, 74 pathogenic or likely pathogenic mutations had been reported. CASE PRESENTATION: Here we describe a compound heterozygote in LYST gene, which was identified in a 4-year-old female patient. The patient showed skin hypopigmentation, sensitivity to light, mild splenomegaly and reduction of platelets in clinical examination. Giant intracytoplasmic inclusions were observed in the bone marrow examination, suggesting the diagnosis of CHS. Amplicon sequencing was performed to detect pathogenic mutation in LYST gene. The result was confirmed by two-generation pedigree analysis base on sanger sequencing. CONCLUSION: A compound heterozygote in LYST gene, consisting of a missense mutation c.5719A > G and an intron mutation c.4863-4G > A, was identified from the patient by using amplicon sequencing. The missense mutation is reported for the first time. Two-generation pedigree analysis showed these two mutations were inherited from the patient's parents, respectively. Our result demonstrated that amplicon sequencing has great potential for accelerating and improving the diagnosis of rare genetic diseases.

Fe-based N-doped dendritic catalysts for catalytic ammoxidation of aromatic aldehydes to aromatic nitriles.

Non-noble-metal-based catalysts for catalyzing the oxidative coupling of aldehydes and ammonia represent an efficient atom-economical synthetic route to produce nitriles. In this study, an effective Fe-modified N-doped carbon catalyst anchored on fibrous silica nanospheres (Fe-N/KCC-1-T) was successfully prepared by a facile strategy. 1,10-Phenanthroline with a strong chelating ability ensured the homogeneous, ultrafine distribution of Fe-based active sites, and the KCC-1 support material effectively enhanced the accessibility to these active sites, which corresponded to center-radial pore channels and a high surface area. As-fabricated Fe-N/KCC-1-T exhibited excellent catalytic performance for the ammoxidation of aldehydes under mild reaction conditions. A series of functionalized aldehydes were efficiently oxidized into the corresponding nitriles by using air as the green oxidant. Moreover, the catalyst was recycled for at least five runs without any clear decrease in the performance. Hence, this study is expected to provide an eco-friendly synthetic route to produce nitriles from easily available aldehydes and ammonia by using a cost-effective catalyst.

Ru nanoclusters confined in porous organic cages for catalytic hydrolysis of ammonia borane and tandem hydrogenation reaction.

The fabrication of narrow-sized metal nanoclusters for heterogeneous catalysis has attracted widespread research attention. Nevertheless, it is still a significant challenge to fabricate highly dispersed metal-nanocluster-based catalysts with high activity and stability. In this study, 1,3,5-benzenetricarboxylate and 1,2-diaminocyclohexane were used as precursors to fabricate porous organic cages (POCs), CC3-R. CC3-R exhibited a high specific surface area and a microporous-mesoporous structure. In addition, ultrafine Ru nanoclusters were successfully encapsulated in CC3-R with high dispersion via impregnation and subsequent reduction, affording Ru nanoclusters with a precisely controlled size of ∼0.65 nm. As-obtained Ru(1.45%)@CC3-R exhibited significantly enhanced catalytic activities toward the hydrolysis of ammonia borane (AB) and exhibited high conversion and selectivity for the tandem hydrogenation of nitroarenes and hydrogenation of quinoline in water under mild conditions. In addition, the Ru(1.45%)@CC3-R catalyst exhibited high stability and good recyclability. This study should provide a novel strategy for fabricating highly dispersed ultrafine nanocluster-based catalysts for various catalysis applications.

Renewable chitosan-derived cobalt@N-doped porous carbon for efficient aerobic esterification of alcohols under air.

The direct oxidation of alcohols to esters through a green and cost-effective strategy is a fascinating chemical synthesis route. In this study, an environmentally friendly N-doped porous carbon encapsulated Co-based nano-catalyst was prepared via a simple carbonization procedure, utilizing renewable chitosan, accessible dicyandiamide and low-cost Co(OAc)2 as co-precursors. The obtained Co@NC-2-T catalysts were successfully used in selective oxidation of aromatic alcohols with methanol to esters under atmospheric reaction conditions. The Co@NC-2-900 catalyst (added with 2 g dicyandiamide and pyrolyzed at 900 °C) shows optimal activity and applicability and can also be reused at least six times in the oxidative esterification of aromatic alcohols with excellent stability. The presence of superoxide anion radicals in the current catalytic system was detected by the EPR method, and a possible mechanism of alcohol oxidation to ester was proposed on this basis. Thus, this study provides a facile, eco-friendly, and highly efficient catalytic system for oxidative esterification of alcohols.

Ultrafine palladium nanoparticles confined in core-shell magnetic porous organic polymer nanospheres as highly efficient hydrogenation catalyst.

The development of porous organic polymer (POP)-based materials with controllable structures is highly desirable for catalysis, drug delivery, and chemical adsorption. In this work, we prepared unique porous magnetic core-shell POP nanospheres (Fe3O4@PDA@POP) through a facile strategy. These nanospheres contained a core of magnetic Fe3O4 nanoparticles (NPs), a hydrophilic intermediate layer of dopamine and a POP outer layer. The Fe3O4@PDA@POP showed high porosity, making it an ideal supporting material for fabricating ultrafine and highly dispersed noble-metal NPs (NMNPs). Thus, highly dispersed ultrafine Pd NPs (1.5-2.1 nm) were confined and stabilized within the pores of Fe3O4@PDA@POP via a reverse double-solvent approach (RDSA) to obtain Fe3O4@PDA@POP@Pd catalyst. The Fe3O4@PDA@POP@Pd-2.5% catalyst showed excellent catalytic performance and recyclability towards the hydrogenation of nitrobenzene, alkenes, and alkynes. Hence, this work can pave the way for the development and application of functionalized POP materials to construct efficient catalytic systems.

Ultrafine Pd nanoparticles immobilized on N-doped hollow carbon nanospheres with superior catalytic performance for the selective oxidation of 5-hydroxymethylfurfural and hydrogenation of nitroarenes.

The fabrication of ultrafine noble metal nanoparticle (NMNP)-based catalysts is significant for heterogeneous catalysis due to their excellent performance for organic transformations. In this study, N-doped micro-mesoporous hollow carbon nanospheres (HCN) with a nitrogen content of ∼3.5 wt% are easily prepared by simple carbonization. Then, ultrafine Pd NPs are immobilized on HCN, affording Pd/HCN as a dual-function catalyst which exhibits superior catalytic activity for the selective oxidation of 5-hydroxymethylfurfural (HMF) and hydrogenation of nitroarenes, under mild reaction conditions. The doping of HCN with nitrogen is beneficial for the high dispersion, anchoring, and particle size control of ultrafine Pd NPs, leading to the maximum utilization of Pd atoms and further enhancing the catalytic activity of Pd/HCN. In addition, the obtained Pd/HCN catalyst exhibits excellent reusability and stability. Hence, this study demonstrates the prospect of developing ultrafine NMNP-supported catalysts with high performance for organic transformations.