Hierarchical porous N-doped carbon supported palladium (Pd/NHPC) as a sustainable catalyst for the reduction of 4-nitrophenol with good activity and lifetime

2017 ◽  
Vol 41 (18) ◽  
pp. 10245-10250 ◽  
Author(s):  
X. X. Wu ◽  
H. Zhou
Keyword(s):  
Catalytic Activity ◽  
High Catalytic Activity ◽  
Good Activity ◽  
Hierarchical Porous ◽  
Supported Palladium

Pd/NHPC synthesized through a facile method exhibited high catalytic activity and reusability toward the reduction of 4-NP.

Facile preparation of a hierarchically porous metal–organic nanocomposite with excellent catalytic performance

RSC Advances ◽  
2016 ◽  
Vol 6 (99) ◽  
pp. 97399-97403 ◽  
Author(s):  
Rui Kuang ◽  
Luyi Zheng ◽  
Ethan Cottrill ◽  
Ning Pan ◽  
Yanhui Chi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Aging Process ◽  
Porous Metal ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Hierarchically Porous ◽  
Hierarchical Porous ◽  
Metal Organic ◽  
Facile Preparation ◽  
Excellent Catalytic Performance

A hierarchical porous MOF nanocrystal, hpCuL (L = 2,4,6-tris(3,5-dicarboxylatephenylamino)-1,3,5-triazine) was prepared via a facile gel-aging process. This nanocomposite exhibits high catalytic activity and stability for the reduction of 4-nitrophenol.

A novel magnetic palladium catalyst for the mild aerobic oxidation of 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid in water

2015 ◽  
Vol 5 (6) ◽  
pp. 3194-3202 ◽  
Author(s):  
Nan Mei ◽  
Bing Liu ◽  
Judun Zheng ◽  
Kangle Lv ◽  
Dingguo Tang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Catalytic Activity ◽  
Palladium Catalyst ◽  
Palladium Nanoparticles ◽  
Aerobic Oxidation ◽  
High Catalytic Activity ◽  
Supported Palladium ◽  
Magnetically Separable ◽  
Furandicarboxylic Acid

Magnetically separable, graphene oxide-supported palladium nanoparticles showed high catalytic activity for the aerobic oxidation of 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid.

scholarly journals Structure-Catalytic Properties Relationship in Friedel Crafts Alkylation Reaction for MCM-36-Type Zeolites Obtained by Isopropanol-Assisted Pillaring

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 299
Author(s):  
Karolina Ogorzały ◽  
Agnieszka Węgrzyn ◽  
Aleksandra Korzeniowska ◽  
Andrzej Sławek ◽  
Andrzej Kowalczyk ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Acid Sites ◽  
Alkylation Reaction ◽  
High Catalytic Activity ◽  
Large Molecules ◽  
External Acid Sites ◽  
Hierarchical Porous ◽  
Acid Centers ◽  
Ir Study

MWW type zeolites are characterized by the presence of zeolitic layers of 2.5 nm thickness, containing 10-member ring sinusoidal channels inside and supercavities with 12-member ring openings located on their surfaces. Expansion and pillaring of layered zeolites increase the access to active sites and can enable or facilitate catalytic activity towards larger reactant molecules. This goal is explored in this work reporting the pillaring of layered zeolite MCM-56 with MWW topology by tetraethylorthosilicate (TEOS) treatment with the assistance of isopropanol, aimed at obtaining hierarchical micro-mesoporous systems. MCM-56 (Si/Al = 12) was synthesized with hexamethyleneimine as a structure-directing and aniline as a structure-promoting agent. Hierarchical porous systems were obtained using two different pillaring methods: (1) with TEOS only and (2) with TEOS mixed with isopropanol. The MWW framework was preserved during swelling/pillaring in both methods. Pillared zeolites obtained via alcohol-assisted pillaring possessed unique intermediate micro-mesopores with the size of about 2 nm. IR study revealed a decrease in the concentration of accessible acid centers upon pillaring. However, the fraction of acid sites on the external surface, accessible for adsorption of large molecules, increased by up to 90%. Catalytic activity was evaluated in the Friedel-Crafts alkylation of mesitylene with benzyl alcohol. Pillaring resulted in reduction of the acid site concentrations, but the materials retained high catalytic activity. Pillaring in the presence of alcohol produced increased turnover frequency values based on the concentrations of the external acid sites.

Hierarchical porous ZIF-8 for hydrogen production via the hydrolysis of sodium borohydride

2020 ◽  
Vol 49 (14) ◽  
pp. 4416-4424 ◽  
Author(s):  
Hani Nasser Abdelhamid
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Production ◽  
Sodium Borohydride ◽  
Terephthalic Acid ◽  
High Catalytic Activity ◽  
Zeolitic Imidazolate Framework ◽  
Hierarchical Porous ◽  
Hydrolysis Of

Terephthalic acid (TPA) is used for the synthesis of hierarchical porous zeolitic imidazolate framework (HPZIF-8) which shows high catalytic activity for the hydrolysis of NaBH4 (2333 mLH2 min−1 gcat−1).

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

Ordered Intermetallic Nanoparticles with High Catalytic Activity Prepared by an Electrochemically Induced Phase Transformation

2019 ◽  
Author(s):  
Du Sun ◽  
yunfei wang ◽  
Kenneth Livi ◽  
chuhong wang ◽  
ruichun luo ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Diffusion Mechanism ◽  
Reduction Reaction ◽  
Atomic Scale ◽  
High Catalytic Activity ◽  
Ambient Conditions ◽  
Magnetic Devices ◽  
Disordered Alloys ◽  
Ordered Intermetallic ◽  
Intermetallic Nanoparticles

<div> <p>The synthesis of alloys with long range atomic scale ordering (ordered intermetallics) is an emerging field of nanochemistry. Ordered intermetallic nanoparticles are useful for a wide variety of applications such as catalysis, superconductors, and magnetic devices. However, the preparation of nanostructured ordered intermetallics is challenging in comparison to disordered alloys, hindering progress in materials development. We report a process for converting colloidally synthesized ordered intermetallic PdBi<sub>2</sub> to ordered intermetallic Pd<sub>3</sub>Bi nanoparticles under ambient conditions by an electrochemically induced phase transition. The low melting point of PdBi<sub>2</sub> corresponds to low vacancy formation energies which enables the facile removal of the Bi from the surface, while simultaneously enabling interdiffusion of the constituent atoms via a vacancy diffusion mechanism under ambient conditions. The resulting phase-converted ordered intermetallic Pd<sub>3</sub>Bi exhibits 11x and 3.5x higher mass activty and high methanol tolerance for the oxygen reduction reaction compared to Pt/C and Pd/C, respectively,which is the highest reported for a Pd-based catalyst, to the best of our knowledge. These results establish a key development in the synthesis of noble metal rich ordered intermetallic phases with high catalytic activity, and sets forth guidelines for the design of ordered intermetallic compounds under ambient conditions.</p> </div>

Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

2020 ◽  
Vol 23 ◽  
Author(s):  
Mohsen Nikoorazm ◽  
Maryam Khanmoradi ◽  
Masoumeh Sayadian
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Sol Gel ◽  
Reaction Times ◽  
Significant Loss ◽  
Spectral Studies ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Solvent Free Conditions ◽  
Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

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