Letter pubs.acs.org/NanoLett
Promotion of Oxygen Reduction by Exsolved Silver Nanoparticles on a Perovskite Scaffold for Low-Temperature Solid Oxide Fuel Cells Yinlong Zhu,† Wei Zhou,*,† Ran Ran,† Yubo Chen,† Zongping Shao,‡,§ and Meilin Liu*,∥ †
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry & Chemical Engineering, Nanjing Tech University, No. 5 Xin Mofan Road, Nanjing 210009, P. R. China ‡ State Key Laboratory of Materials-Oriented Chemical Engineering, College of Energy, Nanjing Tech University, No. 5 Xin Mofan Road, Nanjing 210009, P. R. China § Department of Chemical Engineering, Curtin University, Perth, Western Australia 6845, Australia ∥ Center for Innovative Fuel Cell and Battery Technologies, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245, United States S Supporting Information *
ABSTRACT: Solid oxide fuel cells (SOFCs) have potential to be the cleanest and most efficient electrochemical energy conversion devices with excellent fuel flexibility. To make SOFC systems more durable and economically competitive, however, the operation temperature must be significantly reduced, which depends sensitively on the development of highly active electrocatalysts for oxygen reduction reaction (ORR) at low temperatures. Here we report a novel silver nanoparticle-decorated perovskite oxide, prepared via a facile exsolution process from a Sr0.95Ag0.05Nb0.1Co0.9O3‑δ (SANC) perovskite precursor, as a highly active and robust ORR electrocatalyst for low-temperature SOFCs. The exsolved Sr0.95Ag0.05Nb0.1Co0.9O3‑δ (denoted as e-SANC) electrode is very active for ORR, achieving a very low area specific resistance (∼0.214 Ω cm2 at 500 °C). An anode-supported cell with the new heterostructured cathode demonstrates very high peak power density (1116 mW cm−2 at 500 °C) and stable operation for 140 h at a current density of 625 mA cm−2. The superior ORR activity and stability are attributed to the fast oxygen surface exchange kinetics and the firm adhesion of the Ag nanoparticles to the Sr0.95Nb0.1Co0.9O3−δ (SNC0.95) support. Moreover, the e-SANC cathode displays improved tolerance to CO2. These unique features make the new heterostructured material a highly promising cathode for low-temperature SOFCs. KEYWORDS: Cathode material, oxygen reduction reaction, perovskite, silver nanoparticle, solid oxide fuel cell
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catalyst for oxygen reduction reaction (ORR) with sufficiently high activity and operating stability. Although considerable efforts have been devoted to the development of alternative cathode materials for ORR at reduced temperatures, finding a high-performance ORR electrocatalyst for low-temperature SOFCs (LT-SOFCs) to be operated at
