Platinum nanoparticles with superacid-doped polyvinylpyrrolidone coated carbon nanotubes: electrocatalyst for oxygen reduction reaction in high-temperature proton exchange membrane fuel cell

RSC Advances ◽  
2016 ◽  
Vol 6 (48) ◽  
pp. 41937-41946 ◽  
Author(s):  
S. Pourjafari Amyab ◽  
E. Saievar-Iranizad ◽  
A. Bayat

In order to improve the catalytic activity and durability of proton-exchange-membrane-fuel-cells (PEMFCs), Nafion-free Pt-based catalyst using the superacid-doped polymer coated multiwall carbon nanotubes (MWCNTs) was investigated.

2019 ◽  
Vol 12 (1) ◽  
pp. 37
Author(s):  
Sudirman Sudirman ◽  
Wisnu Ari Adi ◽  
Emil Budianto ◽  
Deni Shidqi K. ◽  
Rike Yudianti

Synthesis of mono-dispersed Pt/MWCNTs has been performed. Platinum nanoparticles (Pt NPs) were grown directly on multiwall carbon nanotubes (MWCNTs) through sol-gel method using NaBH4 as reducing agent.       120 mg of activated MWCNT were weighed and then incorporated into the mixture (1) and sonicated for 2 hours to form the mixture (2). H2PtCl6 was weighed as much as 90 mg and dissolved into 45 mL of ethylene glycol until formed mixture (3). Solution (3) was dropwise every 3 seconds into the mixture (2). After that the mixture was distilled for 12 hours at a rate of 450 rpm. Subsequently the mixture was sonicated for 3 hours, then checked its pH, adjusting the desired pH to 4, 7, or 13 using the mixture 2M NaOH-ethylene glycol. The tests include SEM, EDS, XRD, and TEM for the morphologies and microstructures of the mono-dispersed Pt/MWCNT. The result of SEM observation and the analysis of the element using EDS found that the composite sample looked homogenous and contained element of C (MWCNT) and Pt (platinum). From the XRD shows that the composite Pt/MWCNT of the product synthesized without the reducing agent consists of three phases, namely C (MWCNTs), Pt (platinum), and H2PtH4, while the product synthesized using NaBH4 reducing agent consist of two phases, namely C (MWCNTs) and Pt (platinum ). The TEM image shows that the Pt NPs are spherical in size ~ 5 nm. Pt NPs appear to be attached on MWCNTs, either agglomerated or dispersed on the surface of MWCNTs. This paper will be compared between Pt/MWCNTs synthesis results with and without using NaBH4 reducing agent, as well as dispersed Pt NPs on MWCNTs.


2016 ◽  
Vol 707 ◽  
pp. 23-27
Author(s):  
Pattarakamon Chaiwan ◽  
Thapanee Sarakonsri ◽  
Jantrawan Pumchusak

This research aims to study the effect of the functionalization of the multiwall carbon nanotubes (MWCNTs) on the mechanical property improvement of phenolic composites for bipolar plate applications in proton exchange membrane fuel cells (PEMFC). The MWCNTs were oxidized by strong acid and silanized by silane coupling agent in order to enhance the interfacial adhesion between the MWCNTs and matrix and were used as reinforcement in the phenolic composites. The silanized MWCNTs was found to improve the mechanical properties of the composites; however, they caused the decrease of electrical conductivity due to the wrapping of the MWCNTs with non-conductive silane molecules. Nevertheless, the conductivity of more than 100 S/cm is maintained to meet the DOE requirement of materials for use as bipolar plates.


2018 ◽  
Vol 778 ◽  
pp. 275-282
Author(s):  
Noaman Khan ◽  
Saim Saher ◽  
Xuan Shi ◽  
Muhammad Noman ◽  
Mujahid Wasim Durani ◽  
...  

Highly porous ZIF-67 (Zeolitic imidazole framework) has a conductive crystalline metal organic framework (MOF) structure which was served as a precursor and template for the preparation of nitrogen-doped carbon nanotubes (NCNTs) electrocatalysts. As a first step, the chloroplatinic acid, a platinum (Pt) precursor was infiltrated in ZIF-67 with a precise amount to obtain 0.12 mg.cm-2 Pt loading. Later, the infiltrated structure was calcined at 700°C in Ar:H2 (90:10 vol%) gas mixture. Multi-walled nitrogen-doped carbon nanotubes were grown on the surface of ZIF-67 crystals following thermal activation at 700°C. The resulting PtCo-NCNTs electrocatalysts were deposited on Nafion-212 solid electrolyte membrane by spray technique to study the oxygen reduction reaction (ORR) in the presence of H2/O2 gases in a temperature range of 50-70°C. The present study elucidates the performance of nitrogen-doped carbon nanotubes ORR electrocatalysts derived from ZIF-67 and the effects of membrane electrode assembly (MEA) steaming on the performance of proton exchange membrane fuel cell (PEMFC) employing PtCo-NCNTs as ORR electrocatalysts. We observed that the peak power density at 70°C was 450 mW/cm2 for steamed membrane electrode assembly (MEA) compared to 392 mW/cm2 for an identical MEA without steaming.


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