Cyclic Voltammetry Characterization of Au, Pd, and AuPd Nanoparticles Supported on Different Carbon Nanofibers

Three types of carbon nanofibers (pyrolytically stripped carbon nanofibers (PS), low-temperature heat treated carbon nanofibers (LHT), and high-temperature heat treated carbon nanofibers (HHT)) with different graphitization degrees and surface chemistry have been used as support for Au, Pd, or bimetallic AuPd alloy nanoparticles (NPs). The carbon supports have been characterized using Raman, X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). Moreover, the morphology of the metal nanoparticles was investigated using transmission electron microscopy (TEM) and CV. The different properties of the carbon-based supports (particularly the graphitization degree) yield different electrochemical behaviors, in terms of potential window widths and electrocatalytic effects. Comparing the electrochemical behavior of monometallic Au and Pd and bimetallic AuPd, it is possible to observe the interaction of the two metals when alloyed. Moreover, we demonstrate that carbon surface has a strong effect on the electrochemical stability of AuPd nanoparticles. By tuning the Au-Pd nanoparticles’ morphology and modulating the surface chemistry of the carbon support, it is possible to obtain materials characterized by novel electrochemical properties. This aspect makes them good candidates to be conveniently applied in different fields.

Download Full-text

Ruling Factors in Cinnamaldehyde Hydrogenation: Activity and Selectivity of Pt-Mo Catalysts

Nanomaterials ◽

10.3390/nano11020362 ◽

2021 ◽

Vol 11 (2) ◽

pp. 362

Author(s):

Marta Stucchi ◽

Maela Manzoli ◽

Filippo Bossola ◽

Alberto Villa ◽

Laura Prati

Keyword(s):

Photoelectron Spectroscopy ◽

Pt Nanoparticles ◽

Carbon Support ◽

Catalytic Performance ◽

Acid Sites ◽

Hydrogenation Catalysts ◽

Cinnamaldehyde Hydrogenation ◽

Transmission Electron ◽

Heat Treated ◽

Heating Treatment

To obtain selective hydrogenation catalysts with low noble metal content, two carbon-supported Mo-Pt bimetallic catalysts have been synthesized from two different molybdenum precursors, i.e., Na2MoO4 and (NH4)6Mo7O24. The results obtained by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) combined with the presence and strength of acid sites clarified the different catalytic behavior toward cinnamaldehyde hydrogenation. After impregnating the carbon support with Mo precursors, each sample was used either as is or treated at 400 °C in N2 flow, as support for Pt nanoparticles (NPs). The heating treatment before Pt deposition had a positive effect on the catalytic performance. Indeed, TEM analyses showed very homogeneously dispersed Pt NPs only when they were deposited on the heat-treated Mo/C supports, and XPS analyses revealed an increase in both the exposure and reduction of Pt, which was probably tuned by different MoO3/MoO2 ratios. Moreover, the different acid properties of the catalysts resulted in different selectivity.

Download Full-text

INVESTIGATION OF THE ELECTROCHEMICAL BEHAVIOR OF HEAT-TREATED CARBON BLACKS AND Pt/C CATALYSTS

Surface Review and Letters ◽

10.1142/s0218625x02004001 ◽

2002 ◽

Vol 09 (03n04) ◽

pp. 1443-1452 ◽

Cited By ~ 3

Author(s):

C. D. HUANG ◽

Z. T. XIONG ◽

J. Y. LIN ◽

K. L. TAN

Keyword(s):

Carbon Black ◽

Electrochemical Behavior ◽

Catalyst Support ◽

Carbon Surface ◽

Carbon Blacks ◽

Heat Treated ◽

Platinum Particles ◽

Electro Oxidation ◽

Treated Carbon ◽

Xps Study

In this paper we report the electrochemical behavior of heat-treated carbon blacks and Pt/C catalysts. Cyclic voltammetry indicates that the heat-treated carbon black as catalyst support does not improve the Pt/C catalyst's activity for methanol oxidation. An XPS study of a Pt-loaded carbon black indicates that the amounts of oxidized platinum and oxygen-functional groups on catalysts are decreased when the platinum particles are deposited on the heat-treated carbon surface. These changes in the surface and crystalline structural properties of carbon materials lead to the catalytic activity change in methanol electro-oxidation.

Download Full-text

Understanding the Dielectric Properties of Heat-Treated Carbon Nanofibers at Terahertz Frequencies: a New Perspective on the Catalytic Activity of Structured Carbonaceous Materials

The Journal of Physical Chemistry C ◽

10.1021/jp811226d ◽

2009 ◽

Vol 113 (24) ◽

pp. 10554-10559 ◽

Cited By ~ 27

Author(s):

Edward P. J. Parrott ◽

J. Axel Zeitler ◽

James McGregor ◽

Shu-Pei Oei ◽

Husnu Emrah Unalan ◽

...

Keyword(s):

Catalytic Activity ◽

Dielectric Properties ◽

Carbon Nanofibers ◽

Carbonaceous Materials ◽

Heat Treated ◽

Terahertz Frequencies ◽

New Perspective ◽

Treated Carbon

Download Full-text

Pd–Au Bimetallic Catalysts for the Hydrogenation of Muconic Acid to Bio-Adipic Acid

Catalysts ◽

10.3390/catal11111313 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1313

Author(s):

Sofia Capelli ◽

Ilaria Barlocco ◽

Federico Maria Scesa ◽

Xiaohui Huang ◽

Di Wang ◽

...

Keyword(s):

Adipic Acid ◽

Bimetallic Catalysts ◽

Batch Reactor ◽

Hydrogenation Reaction ◽

Molar Ratio ◽

Muconic Acid ◽

Bimetallic Nanoparticle ◽

Heat Treated ◽

Temperature Heat ◽

Treated Carbon

The hydrogenation reaction of muconic acid, produced from biomass using fermentative processes, to bio-adipic acid is one of the most appealing green emerging chemical process. This reaction can be promoted by catalysts based on a metal belonging to the platinum group, and the use of a second metal can preserve and increase their activity. Pd–Au bimetallic nanoparticle samples supported on high-temperature, heat-treated carbon nanofibers were prepared using the sol immobilization method, changing the Pd–Au molar ratio. These catalysts were characterized by TEM, STEM, and XPS analysis and tested in a batch reactor pressurized with hydrogen, where muconic acid dissolved in water was converted to adipic acid. The synthesized Pd–Au bimetallic catalysts showed higher activity than monometallic Au and Pd material and better stability during the recycling tests. Moreover, the selectivity toward the mono-unsaturated changed by decreasing the Pd/Au molar ratio: the higher the amount of gold, the higher the selectivity toward the intermediates.

Download Full-text

Stabilization of CF4 plasma treated carbon surface by heat treated during and after plasma treatment

Journal of Vacuum Science & Technology A Vacuum Surfaces and Films ◽

10.1116/1.580662 ◽

1997 ◽

Vol 15 (4) ◽

pp. 1937-1942 ◽

Cited By ~ 1

Author(s):

Yori Izumi ◽

Kiichiro Kamata ◽

Masaaki Katoh ◽

Takeo Ohte ◽

Akira Kojima

Keyword(s):

Plasma Treatment ◽

Carbon Surface ◽

Heat Treated ◽

Treated Carbon

Download Full-text

Hydrogen storage in heat-treated carbon nanofibers prepared by the vertical floating catalyst method

Materials Chemistry and Physics ◽

10.1016/s0254-0584(02)00233-x ◽

2003 ◽

Vol 78 (3) ◽

pp. 670-675 ◽

Cited By ~ 24

Author(s):

Hongwei Zhu ◽

Xuesong Li ◽

Lijie Ci ◽

Cailu Xu ◽

Dehai Wu ◽

...

Keyword(s):

Hydrogen Storage ◽

Carbon Nanofibers ◽

Heat Treated ◽

Treated Carbon

Download Full-text

Changes in the Surface Chemistry and Adsorptive Properties of Active Carbon Previously Oxidised and Heat-Treated at Various Temperatures. I. Physicochemical Properties of the Modified Carbon Surface

Adsorption Science & Technology ◽

10.1260/0263617011494402 ◽

2001 ◽

Vol 19 (7) ◽

pp. 565-576 ◽

Cited By ~ 13

Author(s):

H. Grajek ◽

A. Świą;tkowski ◽

Z. Witkiewicz ◽

M. Pakuła ◽

S. Biniak

Keyword(s):

Surface Chemistry ◽

Physicochemical Properties ◽

Active Carbon ◽

Carbon Surface ◽

Heat Treated ◽

Adsorptive Properties

Download Full-text

Synergy Effect of Nitrogen and Molybdenum on Activated Carbon Matrix for Selective Adsorptive Desulfurization: Insights into Surface Chemistry Modification

10.21203/rs.3.rs-322025/v1 ◽

2021 ◽

Author(s):

Musa O Azeez ◽

Abdulkadir Tanimu ◽

Khalid Alhooshani ◽

Saheed A. Ganiyu

Keyword(s):

Activated Carbon ◽

Surface Chemistry ◽

Adsorption Capacity ◽

Surface Area ◽

Photoelectron Spectroscopy ◽

Pore Volume ◽

Carbon Surface ◽

Synergy Effect ◽

Adsorptive Desulfurization ◽

X Ray

Abstract This study reports the synthesis of mesoporous metal-modified nitrogen doped activated carbon (AC-N-Mo) from date seeds by ZnCl2 activation and its applicability for selective adsorptive desulfurization of dibenzothiophene (DBT). The AC-N-Mo exhibits higher adsorption capacity for DBT at 100 mg-S/L with the maximum value of 99.7% corresponding to 19.94 mg-S/g at room temperature than the unmodified carbon with 17.96 mg-S/g despite its highest surface area and pore volume of 1027 m2g− 1 and 0.55 cm3g− 1 respectively. The adsorption capacity breakthrough follows the order AC-N-Mo > AC-Mo > AC > AC-N. AC-N-Mo also displayed excellent selectivity in the presence of aromatics (toluene, naphthalene and 1-methylisoquinoline). The enhancement in the DBT uptake capacities of AC-N-Mo is attributed to synergy effect of nitrogen heteroatom that aid well dispersion of molybdenum nanoparticles on carbon surface thereby improving its surface chemistry and promising textural characteristics. The kinetic studies showed that the DBT adsorption proceeds via pseudo-second order kinetics while the isotherm revealed that both Freundlich and Langmuir fit the data but Freundlich fit the data more accurately for the best performing adsorbent. The physico-chemical properties (surface area, pore volume, carbon content, particle size etc.) of as-prepared adsorbents namely; AC, AC-N, AC-N-Mo and AC-Mo were characterized by N2- physisorption, X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Spectroscopy/Energy Dispersive Spectroscopy (SEM/EDS), Raman Spectroscopy (RS), Fourier Transform Infrared Spectroscopy (FTIR) and Ammonia-Temperature-Programmed Desorption (NH3-TPD).

Download Full-text

Catalytic Performances of Au–Pt Nanoparticles on Phosphorous Functionalized Carbon Nanofibers towards HMF Oxidation

C – Journal of Carbon Research ◽

10.3390/c4030048 ◽

2018 ◽

Vol 4 (3) ◽

pp. 48 ◽

Cited By ~ 1

Author(s):

Sebastiano Campisi ◽

Sofia Capelli ◽

Davide Motta ◽

Felipe Trujillo ◽

Thomas Davies ◽

...

Keyword(s):

Carbon Nanofibers ◽

Photoelectron Spectroscopy ◽

Pt Nanoparticles ◽

Carbon Surface ◽

Protective Agent ◽

Transmission Electron ◽

Functionalized Materials ◽

Furandicarboxylic Acid ◽

Key Parameter ◽

Catalytic Performances

Herein, we reported the utilization of pre-formed Au–Pt nanoparticles deposited on phosphorus functionalized carbons as effective catalysts for the oxidation of 5-hydroxymethylfurfural (HMF) to furandicarboxylic acid (FDCA). Au–Pt nanoparticles have been prepared by a two-step methodology using polyvinyl alcohol (PVA) as protective agent and a combination of NaBH4 and H2 as reducing agents. Three carbon nanofibers (CNFs) with different graphitization degrees have been functionalized through treatment with an H3PO4–HNO3 mixture at 150 °C, in order to incorporate P groups on carbon surface. Surface and structural properties of the synthesized functionalized materials have been investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The structural and surface properties of carbon nanofibers determine the amount of P-functionalities, which is a key parameter affecting the catalytic performances of Au–Pt. Indeed, the highest activity and stability has been achieved for Au–Pt deposited on the sample, which showed the largest amount of P-groups on the surface.

Download Full-text