scholarly journals Recent Advances in Pt-Based Binary and Ternary Alloy Electrocatalysts for Direct Methanol Fuel Cells

2021 ◽  
Author(s):  
Dang Long Quan ◽  
Phuoc Huu Le

The direct methanol fuel cell (DMFC) is among the most promising alternative energy sources for the near future owing to its advantages of simple construction, compact design, high energy density, and relatively high energy-conversion efficiency. Typically, the electrodes in DMFC is comprised of a Pt-based catalysts supported on great potential of carbon materials such as multi-walled carbon nanotubes (MWCNTs), carbon black (CB), graphene, etc. It is desired to develop an electrode with high surface area, good electrical conductivity and suitable porosity to allow good reactant flux and high stability in the fuel cell environment. This chapter will provide recent advances in Pt-based binary and ternary electrocatalysts on carbon supports for high-performance anodes in DMFC. Through studying the effects of composition-, support-, and shape dependent electrocatalysts, further fundamental understanding and mechanism in the development of anode catalysts for DMFC will be provided in details.

2004 ◽  
Vol 3 (1) ◽  
pp. 02
Author(s):  
J. V. C. Vargas

The global economy lives a period of great apprehension regarding energy issues for the near future. The developed countries continue to have a steady growth and the emerging countries increase their rates of economic growth, which causes a continuing increase in global energy demand. In that context, RETERM calls the attention of the readers to the growing need for the search of alternative energy sources to the current oil based global economy. This effort certainly involves focus and work of the energy related scientific community, field in which Thermal Engineering is part of. There are several alternatives currently under consideration. The Department of Energy of the United States of America is currently seriously focused on research and development of alternative energy sources, mainly aiming the independence of external suppliers, such as nuclear energy and the hydrogen economy. Therefore, it is vital to any nation the allocation of financial resources to the development and technological control of new processes that lead to self-sufficiency in energy generation for internal consumption and economic growth. The fuel cell systems will be of critical importance in the possible hydrogen economy scenery for the near future, and they are at the forefront of the emerging technologies for electric power generation for stationary, mobile and portable applications. The high energy conversion efficiencies, extremely low onsite environmental pollution and noise are among their major advantages in comparison to other systems. However, there are major technological and economic hurdles to be overcome prior to their large scale practical implementation. Similarly to nuclear technology, in fuel cell technology it is observed that each research group develops its own know-how independently and with little exchange of information.In this fifth number, we continue to publish the best articles written in English language, presented at the 9th Brazilian Congress of Thermal Engineering and Sciences, ENCIT 2002, held in Caxambu, MG, from October 15th to 18th, 2002, that were selected by the Associate Technical Editors of RETERM, according to the scientific criteria of the journal. The idea is to increase the industrial and scientific impact of the research results presented in the Congress. Additional articles that have been submitted and reviewed in the regular RETERM publication process are also included in the current issue.


Author(s):  
Kimberly McGrath ◽  
Douglas Carpenter

High surface area nanometal particles of nano-cobalt (n-Co) (approx 8 nm particles), produced at QuantumSphere Inc., were blended in various ratios with Pt and Nafion® ionomer, and investigated for their electrocatalytic activity in the oxygen reduction reaction (ORR). The ORR was evaluated by voltammetry using Pt/n-Co blended catalyst on glassy carbon to determine both kinetic activity and as an indicator of direct methanol fuel cell (DMFC) cathode performance. Kinetic enhancement was observed for Pt:n-Co where n-Co is 30–50% (by weight) of the catalyst mixture, including a minimum of 10 mV improvement in the open circuit voltage (OCV). By Tafel slope measurements, it is clear that the mechanism for ORR does not change, however the reaction rate is enhanced by addition of n-Co to Pt in the catalytic ink. For ink compositions similar to those used for standard DMFC cathodes, eliminating 50% of the Pt black resulting in 50% higher energy density while reducing total catalyst cost by roughly 44%.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Guo-Qun Zhang ◽  
Bo Li ◽  
Mao-Cheng Liu ◽  
Shang-Ke Yuan ◽  
Leng-Yuan Niu

Transition metal phosphide alloys possess the metalloid characteristics and superior electrical conductivity and are a kind of high electrical conductive pseudocapacitive materials. Herein, high electrical conductive cobalt phosphide alloys are fabricated through a liquid phase process and a nanoparticles structure with high surface area is obtained. The highest specific capacitance of 286 F g−1 is reached at a current density of 0.5 A g−1. 63.4% of the specific capacitance is retained when the current density increased 16 times and 98.5% of the specific capacitance is maintained after 5000 cycles. The AC//CoP asymmetric supercapacitor also shows a high energy density (21.3 Wh kg−1) and excellent stability (97.8% of the specific capacitance is retained after 5000 cycles). The study provides a new strategy for the construction of high-performance energy storage materials by enhancing their intrinsic electrical conductivity.


2021 ◽  
Author(s):  
Nuray Kizildag

Ceramic materials are well known for their hardness, inertness, superior mechanical and thermal properties, resistance against chemical erosion and corrosion. Ceramic nanofibers were first manufactured through a combination of electrospinning with sol–gel method in 2002. The electrospun ceramic nanofibers display unprecedented properties such as high surface area, length, thermo-mechanical properties, and hierarchically porous structure which make them candidates for a wide range of applications such as tissue engineering, sensors, water remediation, energy storage, electromagnetic shielding, thermal insulation materials, etc. This chapter focuses on the most recent advances in the applications of ceramic nanofibers.


2021 ◽  
Author(s):  
Johanna Schröder ◽  
Jonathan Quinson ◽  
Jacob J. K. Kirkensgaard ◽  
Matthias Arenz

Small angle X-ray scattering (SAXS) is a powerful technique to investigate the degradation of catalyst materials. Ideally such investigations are performed <i>operando</i>, i.e., during a catalytic reaction. An example of <i>operando </i>measurements is to observe the degradation of fuel cell catalysts during an accelerated stress test (AST). Fuel cell catalysts consist of Pt or Pt alloy nanoparticles (NPs) supported on a high surface area carbon. A key challenge of operando SAXS measurements is a proper background subtraction of the carbon support to extract the information of the size distribution of the Pt NPs as a function of the AST treatment. Typically, such operando studies require the use of synchrotron facilities. The background measurement can then be performed by anomalous SAXS (aSAXS) or in a grazing incidence con-figuration. In this work we present a proof-of-concept study demonstrating the use of a laboratory X-ray diffractometer for <i>operando </i>SAXS. Data acquisition of <i>operando </i>SAXS with a laboratory X-ray diffractometer is desirable due to the general challenging and limited accessibility of synchrotron facilities. They become even more crucial under the ongoing and foreseen restrictions related to the COVID-19 pandemic. Although, it is not the aim to completely replace synchrotron-based studies, it is shown that the background subtraction can be achieved by a simple experimental consideration in the setup that can ultimately facilitate <i>operando </i>SAXS measurements at a synchrotron facility. <br>


2016 ◽  
Vol 41 (3) ◽  
pp. 1859-1870 ◽  
Author(s):  
Jing Liu ◽  
Chun-Tao Liu ◽  
Lei Zhao ◽  
Jing-Jia Zhang ◽  
Li-Mei Zhang ◽  
...  

2013 ◽  
Vol 545 ◽  
pp. 77-81
Author(s):  
Korakot Sombatmankhong ◽  
Adrian C. Fisher

One method of increasing number of reaction sites was by the introduction of a porous structure into the electrodes to provide a high surface area for catalyst deposition. This work focused on the development of a method for the fabrication of a porous polypyrrole electrode; a mixture of two monomers (i.e. pyrrole and methylene blue) was simultaneously electropolymerised and one of which was selectively removed from the composite film by solvent extraction. The porous polypyrrole had a suitably porous structure whilst maintaining excellent electrical properties. The application of this novel material to miniaturized fuel cells was shown to have improved power density of 2-fold and 3-fold higher than bulk polypyrrole and bare gold electrodes respectively.


Sign in / Sign up

Export Citation Format

Share Document