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 Warped graphitic layers generated by oxidation of fullerene extraction residue and its oxygen reduction catalytic activity

2019 ◽  
Vol 10 ◽  
pp. 1391-1400 ◽  
Author(s):  
Machiko Takigami ◽  
Rieko Kobayashi ◽  
Takafumi Ishii ◽  
Yasuo Imashiro ◽  
Jun-ichi Ozaki
Keyword(s):  
Catalytic Activity ◽  
Oxygen Reduction ◽  
Active Sites ◽  
Reduction Reaction ◽  
Oxidation Time ◽  
Pt Catalyst ◽  
Oxidation Treatment ◽  
Orr Activity ◽  
Temperature Programmed ◽  
Carbon Catalysts

Carbon-based oxygen reduction reaction (ORR) catalysts are regarded as a promising candidate to replace the currently used Pt catalyst in polymer electrolyte fuel cells (PEFCs); however, the active sites remain under discussion. We predicted that warped graphitic layers (WGLs) are responsible for the ORR catalytic activity in some carbon catalysts (i.e., carbon alloy catalysts (CACs)). To prove our assumption, we needed to use WGLs consisting of carbon materials, but without any extrinsic catalytic elements, such as nitrogen, iron, or cobalt, which effectively enhance ORR activity. The present study employed a fullerene extraction residue as a starting material to construct WGLs. The oxidation of the material at 600 °C exposed the WGLs by removing the surrounding amorphous moieties. Transmission electron microscopy (TEM) observations revealed the formation of WGLs by oxidation treatment at 600 °C in an O2/N2 stream. Extending the oxidation time increased the purity of the WGL phase, but also simultaneously increased the concentration of oxygen-containing surface functional groups as monitored by temperature programmed desorption (TPD). The specific ORR activity increased with oxidation up to 1 h and then decreased with the intensive oxidation treatment. Correlations between the specific ORR activity and other parameters confirmed that the development of the WGL and the increase in the O/C ratio are the competing factors determining specific ORR activity. These results explain the maximum specific ORR activity after 1 h of oxidation time. WGLs were found to lower the heat of adsorption for O2 and to increase the occurrence of heterogeneous electron transfer.

Pd nanoparticles stabilized with phosphine-functionalized porous ionic polymer for efficient catalytic hydrogenation of nitroarenes in water

2020 ◽  
Vol 44 (9) ◽  
pp. 3681-3689 ◽  
Author(s):  
Yizhu Lei ◽  
Zaifei Chen ◽  
Guosong Lan ◽  
Renshu Wang ◽  
Xiao-Yu Zhou
Keyword(s):  
Catalytic Activity ◽  
Catalytic Hydrogenation ◽  
Palladium Nanoparticles ◽  
Pd Nanoparticles ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Ionic Polymer ◽  
Electron Donation ◽  
Nano Size ◽  
Excellent Catalytic Performance

Small palladium nanoparticles stabilized with phosphine-functionalized PIP displayed high catalytic activity for nitroarenes hydrogenation. Nano-size Pd particles, electron-donation effect of phosphine ligand, and surface wettability account for its excellent catalytic performance.

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 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.

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

Te-template approach to fabricating ternary TeCuPt alloy nanowires with enhanced catalytic performance towards oxygen reduction reaction and methanol oxidation reaction

2015 ◽  
Vol 3 (11) ◽  
pp. 5850-5858 ◽  
Author(s):  
Haibo Li ◽  
Cancan Ren ◽  
Shuling Xu ◽  
Lei Wang ◽  
Qiaoli Yue ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Methanol Oxidation ◽  
Geometric Structure ◽  
Oxidation Reaction ◽  
Catalytic Performance ◽  
Reduction Reaction ◽  
Methanol Oxidation Reaction ◽  
Alloy Nanowires

Alloying Pt with both Te and Cu could effectively improve ternary TeCuPt catalytic activity for electronic and geometric structure effects.

Three-steps method with self-sacrificial Co to prepare uniform 5 nm-scale Pt catalyst for the oxygen reduction reaction

2021 ◽  
Author(s):  
Donggang Li ◽  
Yanlong Gong ◽  
Gen Li ◽  
Xiao Lyu ◽  
Zhenqing Dai ◽  
...  
Keyword(s):  
Particle Size ◽  
Catalytic Activity ◽  
Fuel Cells ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reduction Reaction ◽  
Pt Catalyst

The catalytic activity of Pt-based catalysts for fuel cells is largely determined by the particle size and the dispersion of Pt. Normally, the electrodeposition of Pt can not avoid large...

scholarly journals First-Principles Study of Pt-Based Bifunctional Oxygen Evolution & Reduction Electrocatalyst: Interplay of Strain and Ligand Effects

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7814
Author(s):  
Seung-hoon Kim ◽  
Yoonmook Kang ◽  
Hyung Chul Ham
Keyword(s):  
Oxygen Evolution ◽  
Density Functional ◽  
Compressive Strain ◽  
Density Functional Theory Calculations ◽  
Catalytic Performance ◽  
Skin Layer ◽  
Reduction Reaction ◽  
Pt Catalyst ◽  
Surface Separation ◽  
Ligand Effects

We examined the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) of Pt-based Pt3M/Pt nanoalloy catalysts (where M represents a 3d transition metal) for bifunctional electrocatalysts using spin-polarized density functional theory calculations. First, the stability of the Pt3M/Pt catalyst was investigated by calculating the bulk formation energy and surface separation energy. Using the calculated adsorption energies for the OER/ORR intermediates in the modeled catalysts, we predicted the OER/ORR overpotentials and potential limiting steps for each catalyst. The origins of the enhanced catalytic reactivity in Pt3M/Pt catalysts caused by strain and ligand effects are explained separately. In addition, compared to Pt(111), the OER and ORR activities in a Pt3Ni/Ptskin catalyst with a Pt skin layer were increased by 13.7% and 18.4%, respectively, due to the strain and ligand effects. It was confirmed that compressive strain and ligand effects are key factors in improving the catalytic performance of OER/ORR bifunctional catalysts.

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