scholarly journals Ruthenium Supported on Ionically Cross-linked Chitosan-Carrageenan Hybrid MnFe2O4 Catalysts for 4-Nitrophenol Reduction

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 254 ◽  
Author(s):  
Kin Hong Liew ◽  
Tian Khoon Lee ◽  
Mohd Ambar Yarmo ◽  
Kee Shyuan Loh ◽  
Andreia F. Peixoto ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Electrostatic Interactions ◽  
Catalytic Performance ◽  
Reduction Reaction ◽  
Ru Nanoparticles ◽  
Nitrophenol Reduction ◽  
Active Metal ◽  
Wide Range ◽  
Mnfe2o4 Nanoparticles ◽  
Superparamagnetic Properties

Herein, we report a facile procedure to synthesize the hybrid magnetic catalyst (Ru@CS-CR@Mn) using ruthenium (Ru) supported on ionically cross-linked chitosan-carrageenan (CS-CR) and manganese ferrite (MnFe2O4) nanoparticles with excellent catalytic activity. The ionic gelation of CS-CR is acting as a protecting layer to promote the encapsulation of MnFe2O4 and Ru nanoparticles by electrostatic interactions. The presence of an active metal and a CS-CR layer on the as-prepared Ru@CS-CR@Mn catalyst was well determined by a series of physicochemical analyses. Subsequently, the catalytic performances of the Ru@CS-CR@Mn catalysts were further examined in the 4-nitrophenol (4-NP) reduction reaction in the presence of sodium borohydride (reducing agent) at ambient temperature. The Ru@CS-CR@Mn catalyst performed excellent catalytic activity in the 4-NP reduction, with a turnover frequency (TOF) values of 925 h−1 and rate constant (k) of 0.078 s−1. It is worth to mentioning that the Ru@CS-CR@Mn catalyst can be recycled and reused up to at least ten consecutive cycles in the 4-NP reduction with consistency in catalytic performance. The Ru@CS-CR@Mn catalyst is particularly attractive as a catalyst due to its superior catalytic activity and superparamagnetic properties for easy separation. We foresee this catalyst having high potential to be extended in a wide range of chemistry applications.

A facile Pt catalyst regeneration process significantly improves the catalytic activity of Pt–organic composites for the O2 reduction reaction

2015 ◽  
Vol 51 (60) ◽  
pp. 12052-12055 ◽  
Author(s):  
Jing-Fang Huang ◽  
Wen-Yu Chen
Keyword(s):  
Catalytic Activity ◽  
Size Effect ◽  
Catalytic Performance ◽  
Reduction Reaction ◽  
Pt Catalyst ◽  
O2 Reduction ◽  
Organic Composites ◽  
Acidic Conditions ◽  
Nano Size ◽  
Complexation Ability

Combination of the “nano-size” effect and Cl− complexation ability causes massive electrodissolution of Pt under acidic conditions to promote the regeneration of Pt–organic composites and to significantly improve the catalytic performance of the O2 reduction reaction.

scholarly journals A non-structural pure enzyme protein forms a LCST type of stimuli-responsive and reversible hydrogel with novel structure and catalytic activity

2021 ◽  
Author(s):  
J. Nie ◽  
X. Zhang ◽  
Y. Liu ◽  
M.A. Schroer ◽  
W. Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Electrostatic Interactions ◽  
Molecular Engineering ◽  
Solution Temperature ◽  
Stimuli Responsive ◽  
Electron Microscopic ◽  
Saxs Data ◽  
Wide Range ◽  
Protein Hydrogels ◽  
Terminal Domains

AbstractHydrogels have a wide range of applications such as in biomedicine, cosmetics and soft electronics. Compared to polymer hydrogels based on covalent bonding, protein hydrogels offer distinct advantages owing to their biocompatibility and better access to molecular engineering. However, pure and natural protein hydrogels have been seldom reported except for structural proteins like collagen and silk fibrin. Here, we report the unusual ability and mechanism of a unique natural enzyme, lipoate-protein ligase A (LplA) of E. coli to self-assemble into a stimuli-responsive and reversible hydrogel of the low critical solution temperature (LCST) type. This is the first globular and catalytic protein found to form a hydrogel in response to temperature, pH and the presence of ions. Protein structure based analysis reveals the key residues responsible for the gel formation and mutational studies confirms the essential roles of hydrogen bonding between the C-terminal domains and electrostatic interactions in the N-terminal domains. Characterization of phase transitions of wild type LplA and its mutants using small angle X-ray scattering (SAXS) yields details of the gelation process from initial dimer formation over a pre-gel-state to full network development. Further electron microscopic analyses and modeling of SAXS data suggest an unusual interlinked ladder-like structure of the macroscopic crosslinking network with dimers as ladder steps. The unique features of this first reported protein hydrogel may open up hitherto inaccessible applications, especially those taking advantage of the inherent catalytic activity of LplA.

Facet-dependent Catalysis of CuNi Nanocatalysts toward 4–Nitrophenol Reduction Reaction

MRS Advances ◽  
2020 ◽  
Vol 5 (27-28) ◽  
pp. 1491-1496
Author(s):  
Can Li ◽  
Yiliang Luan ◽  
Bo Zhao ◽  
Amar Kumbhar ◽  
Xiaobo Chen ◽  
...  
Keyword(s):  
Sodium Borohydride ◽  
Catalytic Performance ◽  
Reduction Reaction ◽  
High Rate ◽  
Colloidal Synthesis ◽  
Pseudo First Order Reaction ◽  
Nitrophenol Reduction ◽  
Crystallographic Facets ◽  
Capping Ligands ◽  
Synthesis Approach

ABSTRACTWe report a facile method to fabricate CuNi nano-octahedra and nanocubes using a colloidal synthesis approach. The CuNi nanocrystals terminated with exclusive crystallographic facets were controlled and achieved by a group of synergetic capping ligands in a hot solution system. Specifically, the growth of {111}-bounded CuNi nano-octahedra is derived by a thermodynamic control, whereas the generation of {100}-terminated CuNi nanocubes is steered by a kinetic capping of chloride. Using a reduction of 4-nitrophenol with sodium borohydride as a model reaction, CuNi nano-octahedra and nanocubes demonstrated a strong facet-dependence due to their different surface energies although both exhibited remarkable catalytic activity with the high rate constant over mass (k/m). A kinetic study indicated that this is a pseudo first-order reaction with an excess of sodium borohydride. CuNi nanocubes as the catalysts showed better catalytic performance (k/m = 385 s-1•g-1) than the CuNi nano-octahedra (k/m = 120 s-1•g-1), indicating that 4-nitrophenol and hydrogen were adsorbed on the {100} facets with their molecules parallel to the surface much easier than those on {111} facets.

Enhanced Catalytic Activity of Magnetic Bimetallic Ag–Au Nanoparticles Mediated by Surface Plasmon Resonance

2021 ◽  
Vol 21 (5) ◽  
pp. 3107-3114
Author(s):  
Zhuo-Rui Li ◽  
Geng Zhu ◽  
Guo-Zhi Han
Keyword(s):  
Catalytic Activity ◽  
Surface Plasmon Resonance ◽  
Metal Nanoparticles ◽  
Noble Metal ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Au Nanoparticles ◽  
Catalytic Performance ◽  
Reduction Reaction ◽  
Noble Metal Nanoparticles

We firstly discover the enhanced catalytic activity of magnetic noble metal nanoparticles mediated by surface plasmon resonance. Under light irradiation with certain wavelength, the catalytic performance of magnetic noble metal nanoparticles shows changes with different degrees and directions that are associated with the surface plasmon resonance (SPR) of the noble metal. Moreover, the coupling of silver and gold allows the catalytic performance of magnetic bimetallic Ag–Au nanoparticles to show more positive response to surface plasmon resonance. The magnetic bimetallic Ag–Au nanoparticles show excellent catalytic performance toward the reduction reaction of aromatic nitro group, and corresponding rate constant of the catalytic reduction reaction increases about three times with light irradiation.

scholarly journals Size controlled green synthesis of gold nanoparticles using Coffea arabica seed extract and their catalytic performance in 4-nitrophenol reduction

RSC Advances ◽  
2018 ◽  
Vol 8 (44) ◽  
pp. 24819-24826 ◽  
Author(s):  
N. K. R. Bogireddy ◽  
U. Pal ◽  
L. Martinez Gomez ◽  
V. Agarwal
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Green Synthesis ◽  
Coffea Arabica ◽  
Room Temperature ◽  
Catalytic Performance ◽  
Seed Extract ◽  
Size Dependent ◽  
Nitrophenol Reduction ◽  
Size Controlled

Size dependent catalytic activity of AuNPs synthesized at room temperature from Coffea arabica seed extract.

scholarly journals Ni–Cu High-Loaded Sol–Gel Catalysts for Dehydrogenation of Liquid Organic Hydrides: Insights into Structural Features and Relationship with Catalytic Activity

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2017
Author(s):  
Yuliya Gulyaeva ◽  
Maria Alekseeva (Bykova) ◽  
Olga Bulavchenko ◽  
Anna Kremneva ◽  
Andrey Saraev ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Sol Gel ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Structural Features ◽  
Atomic Ratio ◽  
Fixed Bed Reactor ◽  
High Catalytic Activity ◽  
Wide Range ◽  
Structure Reactivity Relationship

The heightened interest in liquid organic hydrogen carriers encourages the development of catalysts suitable for multicycle use. To ensure high catalytic activity and selectivity, the structure–reactivity relationship must be extensively investigated. In this study, high-loaded Ni–Cu catalysts were considered for the dehydrogenation of methylcyclohexane. The highest conversion of 85% and toluene selectivity of 70% were achieved at 325 °C in a fixed-bed reactor using a catalyst with a Cu/Ni atomic ratio of 0.23. To shed light on the relationship between the structural features and catalytic performance, the catalysts were thoroughly studied using a wide range of advanced physicochemical tools. The activity and selectivity of the proposed catalysts are related to the uniformity of Cu distribution and its interaction with Ni via the formation of metallic solid solutions. The method of introduction of copper in the catalyst plays a crucial role in the effectiveness of the interaction between the two metals.

scholarly journals Influence of nickel doping on MnO2 nanoflowers as electrocatalyst for oxygen reduction reaction

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Ababay Ketema Worku ◽  
Delele Worku Ayele ◽  
Nigus Gabbiye Habtu
Keyword(s):  
Cyclic Voltammetry ◽  
Catalytic Activity ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Large Scale ◽  
Catalytic Performance ◽  
Reduction Reaction ◽  
Nickel Concentration ◽  
List Type ◽  
Nickel Doping

Abstract Doping is promising strategy for the alteration of nanomaterials to enhance their optical, electrical, and catalytic activities. The development of electrocatalysts for oxygen reduction reactions (ORR) with excellent activity, low cost and durability is essential for the large-scale utilization of energy storage devices such as batteries. In this study, MnO2 and Ni-doped MnO2 nanowires were prepared through a simple co-perception technique. The influence of nickel concentration on electrochemical performance was studied using linear sweep voltammetry and cyclic voltammetry. The morphological, thermal, structural, and optical properties  of MnO2 and Ni-doped MnO2 nanowires were examined by SEM, ICP-OES, FT-IR, XRD, UV–Vis, BET and TGA/DTA. Morphological analyses showed that pure MnO2 and Ni-doped MnO2 had flower-like and nanowire structures, respectively. The XRD study confirmed the phase transformation from ε to α and β phases of MnO2 due to the dopant. It was also noted from the XRD studies that the crystallite sizes of pure MnO2 and Ni-doped MnO2 were in the range of 2.25–6.6 nm. The band gaps of MnO2 and 0.125 M Ni-doped MnO2 nanoparticles were estimated to be 2.78 and 1.74 eV, correspondingly, which can be seen from UV–Vis. FTIR spectroscopy was used to determine the presence of functional groups and M–O bonds (M = Mn, Ni). The TGA/TDA examination showed that Ni-doping in MnO2 led to an improvement in its thermal properties. The cyclic voltammetry  results exhibited that Ni-doped MnO2 nanowires have remarkable catalytic performance for ORR in 0.1 M KOH alkaline conditions. This work contributes to the facile preparation of highly active and durable catalysts with improved catalytic performance mainly due to the predominance of nickel. Article Highlights MnO2 and Ni-doped MnO2 nanowires were synthesized via a facile co-perception approach. Nickel doping in MnO2 induces the formation of wire-like nanostructures. Nickel doping enhances the electrochemical activity and thermal stability of MnO2 nanoflowers. The addition of nickel into MnO2 promoted the catalytic activity for oxygen reduction reaction. A higher catalytic activity was achieved in 0.125 M Ni-MnO2 nanowires. Graphic abstract

Magnetic N-doped Co–carbon composites derived from metal organic frameworks as highly efficient catalysts for p-nitrophenol reduction reaction

2018 ◽  
Vol 47 (10) ◽  
pp. 3321-3328 ◽  
Author(s):  
Haoyang Zhao ◽  
Lang Zhao
Keyword(s):  
Catalytic Activity ◽  
Reaction Kinetics ◽  
Conversion Efficiency ◽  
Metal Organic Frameworks ◽  
Carbon Matrix ◽  
Reduction Reaction ◽  
Carbon Composites ◽  
Nitrophenol Reduction ◽  
Metal Organic ◽  
One Step

Magnetic nitrogenous cobalt–carbon composites were synthesized via one-step calcination of N-ZIF-67 as a strategy to introduce metal and N atoms into a conductive carbon matrix, and were applied as catalysts in the reduction of 4-NP by NaBH4. N-Co@C-800-3 exhibited much better catalytic activity, in terms of both conversion efficiency and reaction kinetics, compared to the others.

Uniform Ni/SiO2@Au magnetic hollow microspheres: rational design and excellent catalytic performance in 4-nitrophenol reduction

Nanoscale ◽  
2014 ◽  
Vol 6 (12) ◽  
pp. 7025-7032 ◽  
Author(s):  
Shenghuan Zhang ◽  
Shili Gai ◽  
Fei He ◽  
Yunlu Dai ◽  
Peng Gao ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Catalytic Activity ◽  
Rational Design ◽  
Au Nanoparticles ◽  
Catalytic Performance ◽  
Hollow Microspheres ◽  
Nitrophenol Reduction ◽  
Excellent Catalytic Performance

Uniform Ni/SiO2 magnetic hollow microspheres were prepared by an in situ thermal decomposition and reduction route. Tiny Au nanoparticles (5 nm) were linked to Ni/SiO2 microspheres. The as-prepared Ni/SiO2@Au catalysts exhibited excellent catalytic activity for 4-nitrophenol reduction.

Engineering CuOx–ZrO2–CeO2 nanocatalysts with abundant surface Cu species and oxygen vacancies toward high catalytic performance in CO oxidation and 4-nitrophenol reduction

CrystEngComm ◽  
2020 ◽  
Vol 22 (23) ◽  
pp. 4005-4013 ◽  
Author(s):  
Baolin Liu ◽  
Yizhao Li ◽  
Shaojun Qing ◽  
Kun Wang ◽  
Jing Xie ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxygen Vacancies ◽  
Catalytic Performance ◽  
Solvent Free ◽  
Metal Species ◽  
Synthetic Strategy ◽  
Nitrophenol Reduction ◽  
Active Metal ◽  
Excellent Catalytic Performance

CuOx–ZrO2–CeO2 nanocrystalline catalysts were designed and synthesized by a solvent-free synthetic strategy, and exhibited excellent catalytic performance owing to the increased oxygen vacancies and better dispersed active metal species.

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