Saturday, 3 September 2016

Enhancement of ORR activities by Pt nanoclusters decorated on ordered mesoporous porphyrinic carbons

Enhancement of oxygen reduction reaction activities by Pt nanoclusters decorated on ordered mesoporous porphyrinic carbons

J. Mater. Chem. A, 2016,4, 5869-5876
DOI: 10.1039/C5TA09915C
Received 05 Dec 2015, Accepted 06 Mar 2016
First published online 08 Mar 2016

Sun-Mi Hwang,a  YongMan Choi,b  Min Gyu Kim,c  Young-Jun Sohn,a  Jae Yeong Cheon,d  Sang Hoon Joo,d, e  Sung-Dae Yim,a  Kurian A. Kuttiyiel,f  Kotaro Sasaki,f  Radoslav R. Adzicf  and Gu-Gon Park*a

* Corresponding authors
a Fuel Cell Laboratory, Korea Institute of Energy Research (KIER), Daejeon 305-343, South Korea
E-mail: gugon@kier.re.kr
b SABIC Technology Center, Riyadh 11551, Saudi Arabia
c Pohang Accelerator Laboratory, Pohang 790-784, Republic of Korea
d Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South Korea
e School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South Korea
f Chemistry Department, Brookhaven National Laboratory, Upton, USA

Abstract

The high cost of Pt-based membrane electrode assemblies (MEAs) is a critical hurdle for the commercialization of polymer electrolyte fuel cells (PEFCs). Recently, non-precious metal-based catalysts (NPMCs) have demonstrated much enhanced activity but their oxygen reduction reaction (ORR) activity is still inferior to that of Pt-based catalysts resulting in a much thicker electrode in the MEA. For the reduction of mass transport and ohmic overpotential we adopted a new concept of catalyst that combines an ultra-low amount of Pt nanoclusters with metal–nitrogen (M–Nx) doped ordered mesoporous porphyrinic carbon (FeCo–OMPC(L)). The 5 wt% Pt/FeCo–OMPC(L) showed a 2-fold enhancement in activities compared to a higher loading of Pt. Our experimental results supported by first-principles calculations indicate that a trace amount of Pt nanoclusters on FeCo–OMPC(L) significantly enhances the ORR activity due to their electronic effect as well as geometric effect from the reduced active sites. In terms of fuel cell commercialization, this class of catalysts is a promising candidate due to the limited use of Pt in the MEA.


Read more at: http://pubs.rsc.org/en/Content/ArticleLanding/2016/TA/C5TA09915C#!divAbstract