scholarly journals Modulating Catalytic Activity and Durability of PtFe Alloy Catalysts for Oxygen Reduction Reaction Through Controlled Carbon Shell Formation

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1491 ◽  
Author(s):  
Youngjin Kim ◽  
A. Anto Jeffery ◽  
Jiho Min ◽  
Namgee Jung

Demand on synthetic approaches to high performance electrocatalyst with enhanced durability is increasing for fuel cell applications. In this work, we present a facile synthesis of carbon shell-coated PtFe nanoparticles by using acetylacetonates in metal precursors as carbon sources without an additional polymer coating process for the carbon shell formation. The carbon shell structure is systematically controlled by changing the annealing conditions such as the temperature and gas atmosphere. PtFe catalysts annealed at 700 °C under H2-mixed N2 gas show much higher oxygen reduction reaction (ORR) activity and superior durability compared to a Pt catalyst due to the ultrathin and porous carbon shells. In addition, when increasing the annealing temperature, the carbon shells encapsulating the PtFe nanoparticles improves the durability of the catalysts due to the enhanced crystallinity of the carbon shells. Therefore, it is demonstrated that the developed hybrid catalyst structure with the carbon shells not only allows the access of reactant molecules to the active sites for oxygen reduction reaction but also prevents the agglomeration of metal nanoparticles on carbon supports, even under harsh operating conditions. The proposed synthetic approach and catalyst structure are expected to provide more insights into the development of highly active and durable catalysts for practical fuel cell applications.

2019 ◽  
Vol 1155 ◽  
pp. 55-69
Author(s):  
Nabila A. Karim ◽  
Nor Shahirah Shamsul ◽  
Siti Kartom Kamarudin

The platinum (Pt) degradation, poisoning and carbon corrosion in acidic fuel cell has led to explore the research in alkaline fuel cell. However, the high cost of Pt has brought a lot of studies to find replacement for Pt catalyst. Due to that, silver metal is selected as non-Pt catalyst and supported by the nitrogen and phosphorus-doped on graphene for oxygen reduction reaction in alkaline medium. The adsorption energy and mechanism of the oxygen reduction reaction is studied by using density functional theory (DFT) calculation. The support catalyst of graphene is doped with three atom nitrogen and phosphorus namely as N3 and P3, respectively. The Ag supported on N3 and P3 are tested on O2, OOH, O and OH species. There are two types adsorption of O2 on N3 and P3 which is side and end-on adsorption configuration. The N3-Ag has similar adsorption energy for both configurations, but P3-Ag has low adsorption energy by end-on adsorption configuration. The effect of doped atoms on graphene also have been tested on O2, OOH, O and OH species. The result shows that increasing nitrogen doping atom has decreased the adsorption energy of O2 and vice versa on phosphorus atoms. A single phosphorus doping atom on graphene has shown the lowest adsorption energy, but the end-on configuration of P3-Ag has shown most stable adsorption. The schematic free energy profile shows that both N3-Ag and P3-Ag have high possibilities to be followed in oxygen reduction reaction mechanism but P3-Ag has advantage due to stable adsorption as non-Pt catalyst. The Ag metal supported on nitrogen and phosphorus-doped graphene show promising result to be a catalyst in alkaline fuel cell.


2010 ◽  
Vol 55 (8) ◽  
pp. 2622-2628 ◽  
Author(s):  
Hui Li ◽  
Ken Tsay ◽  
Haijiang Wang ◽  
Shaohong Wu ◽  
Jiujun Zhang ◽  
...  

2018 ◽  
Vol 115 ◽  
pp. 226-237 ◽  
Author(s):  
Luigi Osmieri ◽  
Ricardo Escudero-Cid ◽  
Alessandro H.A. Monteverde Videla ◽  
Pilar Ocón ◽  
Stefania Specchia

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