Delivered by Ingenta to: State University of New York at Binghamton IP: 46.148.127.225 On: Thu, 01 Jun 2017 19:38:53 Copyright: American Scientific Publishers Copyright © 2017 American Scientific Publishers All rights reserved Printed in the United States of America Article Journal of Nanoscience and Nanotechnology Vol. 17, 2991–2998, 2017 www.aspbs.com/jnn Dealloyed Nanoporous Pt-Based Alloys as High Performance Anode Catalysts for Direct Alcohol Fuel Cells Koolath Ramakrishnan Deepthi 1 2 , Tsubasa Imai 3 , Ya Xu 1 , Arivuoli Dakshanamoorthy 2 , Gubbala V. Ramesh 1 * , and Hideki Abe 1 * 1 National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan 2 Crystal Growth Centre, Anna University, Chennai 600025, Tamil Nadu, India 3 Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Saitama 338-8570, Japan Pt-based nanoporous alloys of platinum aluminum (np-PtAl), platinum aluminum nickel (np-PtAlNi) and platinum aluminum cobalt (np-PtAlCo) were synthesized from the respective bulk alloys through a slow dealloying process in 1 M NaOH aqueous solution at room temperature. Powder X-ray diffraction (pXRD) indicated the incorporation of Co/Ni metals in PtAl matrices. Transmission elec- tron microscope (TEM) exposed the nanoporous nature of the synthesized nanoporous alloys and the elemental mapping by Energy Dispersion Spectroscope (EDS) exhibited the uniform distribu- tion of respective elements in the nanoporous alloys. The np-PtAlNi demonstrated much higher mass activity and durability for the electro-oxidation of methanol and ethanol than the np-PtAl, np- PtAlCo or commercial Pt nanoparticles (Pt-NPs, particle size <50 nm). Also the np-PtAlNi has better CO-poisoning tolerance than the np-PtAl, np-PtAlCo or commercial Pt NPs. The incorpora- tion of Ni/Co elements have reduced the use of precious metal Pt but improved the activity towards alcohol oxidation. The synthesized nanoporous alloys are promising candidates as anode catalysts in Direct Alcohol Fuel Cells (DAFCs). Keywords: Nanoporous, Dealloying, Electro-Oxidation, Direct Alcohol Fuel Cell. 1. INTRODUCTION Energy-harvesting from small molecules is very crucial to meet the energy and environmental challenges. Direct alcohol fuel cell (DAFC’s) is one of the most feasible technologies as they can achieve pollution-less conver- sion of chemical to electrical energy at a much higher efficiency than combustion engines. Platinum (Pt) and its alloys are the most investigated anode electro-catalyst for the DAFC’s, but current Pt-based anode electro- catalysts possess poor stability and are highly suscepti- ble to CO-poisoning. 1 The thrust to synthesize unexplored metal nanostructures for more active and poisoning- tolerant electro-catalyst still continues. Though several methods have developed to synthesize unexplored nanostructures, great efforts have been put on to develop a unified technology to control the composi- tion, structure and functionality of these nanostructures. * Authors to whom correspondence should be addressed. The novel concept of “nanoarchitectonics” proposed by Aono, 2 serves this purpose. 3 Nanoarchitectonics har- monizes the mutual interactions between the compo- nents to build up hyperfine structures. This concept has recently been implemented in many research area includ- ing batteries, 4 catalysis, 5 physicochemical fabrication, 6 and biomedical applications. 7 Catalytic nanoarchitectonics have concentrated particularly on tailoring the structure of catalysts, to maximize the energy efficiency and minimize the materials cost. Introducing porosity in the bulk crystal structure is one such method of structure tailoring. In the past two decades, researchers have an enormous interest on the nanoporous metallic structures because of the wide range of applications such as sensing, 8 fuel cells 9 and catalysis. 10 Among the several methods devel- oped for the synthesis of porous nanostructures, dealloy- ing process 11 is the most exploited method. Well-defined 3D nanoporous structures can be evolved from bulk alloys through the simple dealloying process. Liu et al. reported J. Nanosci. Nanotechnol. 2017, Vol. 17, No. 5 1533-4880/2017/17/2991/008 doi:10.1166/jnn.2017.13082 2991