이중층 페로브스카이트에서 금속 나노입자 용리현상을 통한 고체산화물 연료전지용 연료극 개발

Abstract

Solid oxide fuel cells (SOFCs) have attracted attention as a promising electrochemical energy conversion device due to their excellent energy conversion efficiency, low environmental pollution, and high fuel flexibility. Generally, Ni-based composite anode has been widely used as the SOFC anode material because Ni has high catalytic activity and electrical conductivity in H2 fuel. However, the Ni-based anode materials suffer from several drawbacks in hydrocarbon fuels, such as low tolerance to redox cycling, sulfur poisoning, and carbon coking. In this regard, extensive efforts have been devoted to develop Ni-free ceramic materials and surface modification technologies. Among the surface modification methods, an exsolution has been received attention because of its special properties. The catalytically active transition metals are incorporated on the B-site of perovskite oxide (ABO3) during synthesis in air, and then the metals are exsolved from the perovskite oxide in reducing atmosphere. The exsolution evenly makes electro-catalytic nanoparticles on the electrode surface, which can suppress carbon coking and increase redox stability. Here, we selected PrBaMn2O5+ (PBMO) as the parent layered perovskite oxide, and doped its B-site with various transition metals. The exsolution of the transition metals is confirmed by density functional theory (DFT) calculations and a transmission electron microscopy (TEM) analysis.