scholarly journals Enhanced Methanol Oxidation Activity of PtRu/C100−xMWCNTsx (x = 0–100 wt.%) by Controlling the Composition of C-MWCNTs Support

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 571
Author(s):  
Dang Long Quan ◽  
Phuoc Huu Le

PtRu nanoparticles decorated on carbon-based supports are of great interest for direct methanol fuel cells (DMFCs). In this study, PtRu alloy nanoparticles decorated on carbon Vulcan XC-72 (C), multi-walled carbon nanotubes (MWCNTs), and C-MWCNTs composite supports were synthesized by co-reduction method. As a result, PtRu nanoparticles obtained a small mean size (dmean = 1.8–3.8 nm) with a size distribution of 1–7 nm. We found that PtRu/C60MWCNTs40 possesses not only high methanol oxidation activity, but also excellent carbonaceous species tolerance ability, suggesting that C-MWCNTs composite support is better than either C or MWCNTs support. Furthermore, detailed investigation on PtRu/C100−xMWCNTsx (x = 10–50 wt.%) shows that the current density (Jf), catalyst tolerance ratio (Jf/Jr), and electron transfer resistance (Ret) are strongly affected by C-MWCNTs composition. The highest Jf is obtained for PtRu/C70MWCNTs30, which is considered as an optimal electrocatalyst. Meanwhile, both PtRu/C70MWCNTs30 and PtRu/C60MWCNTs40 exhibit a low Ret of 5.31–6.37 Ω·cm2. It is found that C-MWCNTs composite support is better than either C or MWCNTs support in terms of simultaneously achieving the enhanced methanol oxidation activity and good carbonaceous species tolerance.

2000 ◽  
Vol 6 (S2) ◽  
pp. 24-25
Author(s):  
R.M. Stroud ◽  
J.W. Long ◽  
K.E. Swider ◽  
D.R. Rolison

Direct methanol fuel cells (DMFCs) offer a simpler, safer technology for point-of-use power sources compared to other hydrogen fuel cells, by avoiding the need to store hydrogen fuel or to carry out the reformation of hydrocarbons. The direct methanol oxidation electrocatalyst of choice is a nanoscale black consisting of a 50:50 atom % mixture of Pt and Ru. It has recently become known that these presumed bimetallic alloys in fact contain an array of metal, oxide and hydrous phases, which are easily misidentified in routine x-ray diffraction measurements due to particle size-broadening and poor crystallinity. By combining transmission electron microscopy, electrochemistry and thermogravimetric studies, we demonstrate here that the route to improved catalytic activity is not by phase purification of the bimetallic alloys, but instead phase engineering of hydrous ruthenium oxide and Pt mixtures.


2021 ◽  
Vol 11 (1) ◽  
pp. 94-98
Author(s):  
Quan Dang Long ◽  
An Nguyen Minh ◽  
Vinh Thach Phuc ◽  
Ngan Nguyen Thi Thanh ◽  
Lil Owin Khưu ◽  
...  

In this work, carbon Vulcan XC-72 (C) and carbon nanotubes (CNTs) supported ternary platinum-ruthenium-iron (PtRuFe) and platinum-ruthenium-nickel (PtRuNi) alloy nanoparticles have been synthesized by a co-reduction method. The catalyst samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and cyclic voltammetry (CV). The results show that ternary alloy catalysts are always better than binary alloy catalysts. In particular, PtRuNi is the best catalyst for methanol oxidation reaction. 


NANO ◽  
2016 ◽  
Vol 11 (02) ◽  
pp. 1650022 ◽  
Author(s):  
Chunhui Tan ◽  
Juhui Sa ◽  
Feipeng Cai ◽  
Bo Jiang ◽  
Gai Yang ◽  
...  

PtRu nanoparticles (NPs) supported on acid treated multiwall carbon nanotubes (Pt1Ru1/MWCNTs) were prepared by a modified polyol method without adding any other surfactant or protective agent. The structural and compositional properties of the as-obtained samples were characterized by transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and X-ray photoelectron (XPS) spectroscopy. The electrocatalytic performance of the catalyst was evaluated by cyclic voltammetry (CV), CO stripping voltammetry and chronoamperometry, indicating a high catalytic activity, excellent CO tolerance and stability for methanol oxidation. Interestingly, a series of accurate controllable experiments have been designed to explore the enhancement mechanism of Pt1Ru1/MWCNTs for methanol oxidation reaction. Most importantly, Pt1Ru1/MWCNTs composites were used as an anode catalyst in the direct methanol fuel cells (DMFCs) exhibiting outstanding power density (126.1 mW/cm[Formula: see text] 1.7 times higher than that of the commercial catalyst of Pt1Ru1/C (74.1 mW/cm[Formula: see text] (E-TEK).


2019 ◽  
Vol 9 (15) ◽  
pp. 4118-4124 ◽  
Author(s):  
Reza Alipour Moghadam Esfahani ◽  
Reza B. Moghaddam ◽  
E. Bradley Easton

The strong metal–support interaction in Pt/Ti3O5Mo0.2Si0.4 enhances the methanol oxidation activity by decreasing the charge transfer resistance and activation energy.


2001 ◽  
Vol 7 (S2) ◽  
pp. 1112-1113
Author(s):  
Rhonda M. Stroud ◽  
Jeffrey W. Long ◽  
Karen E. Swider-Lyons ◽  
Debra R. Rolison

To address how the chemical and structural heterogeneity of Pt50Ru50 nanoparticles affects methanol oxidation activity, we have employed an arsenal of transmission electron microscopy techniques (conventional bright field-imaging, selected area diffraction, atomic-resolution lattice imaging, electron-energy loss spectroscopy, and energy-dispersive x-ray spectroscopy) to characterize 2.5-nm particles in differing oxidation and hydration states. Our studies demonstrate that electrocatalysts containing a high fraction of Ru-rich hydrous oxide, as apposed to the anhydrous PtRu bimetallic alloy, have as much as 250x higher methanol oxidation activityThe nominally 2.5-nm Pt50Ru50 particles were studied in as-received, reduced and reoxidized forms. The reducing treatment consisted of 2 h at 100 °C in flowing 10% PL/argon mixture. For re-oxidation, the reduced particles were heated for 20 h at 100 °C in an H2O-saturated oxygen atmosphere. The particles were suspended in methanol, and pipetted onto holey-carboncoated Cu grids for TEM studies.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
S. S. Mahapatra ◽  
S. Shekhar ◽  
B. K. Thakur ◽  
H. Priyadarshi

Electropolymerization of aniline at the graphite electrodes was achieved by potentiodynamic method. Electrodeposition of Pd (C-PANI-Pd) and Ni (C-PANI-Ni) and codeposition of Pd-Ni (C-PANI-Pd-Ni) microparticles into the polyaniline (PANI) film coated graphite (C-PANI) were carried out under galvanostatic control. The morphology and composition of the composite electrodes were obtained using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) techniques. The electrochemical behavior and electrocatalytic activity of the electrode were characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometric (CA) methods in acidic medium. The C-PANI-Pd-Ni electrode showed an improved catalytic performance towards methanol oxidation in terms of lower onset potential, higher anodic oxidation current, greater stability, lower activation energy, and lower charge transfer resistance. The enhanced electrocatalytic activity might be due to the greater permeability of C-PANI films for methanol molecules, better dispersion of Pd-Ni microparticles into the polymer matrixes, and the synergistic effects between the dispersed metal particles and their matrixes.


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