KAIST · Materials Science
우철 정 교수 연구실은 고체 산화물 연료전지 및 전기화학 장치의 핵심 소재인 퍼보스카이트 산화물과 나노캐리어 촉매의 표면화학, 나노입자 형성 메커니즘, 그리고 기계적·화학적 안정성을 깊이 있게 연구하고 있습니다. 특히, ex-solution을 통한 나노캐리어의 정밀 제어와 표면 재결합 거동을 분석하여 고성능·내구성 있는 전기화학 소자를 설계하는 데 초점을 맞추고 있습니다. 또한, 고온에서의 산소 환원 반응 메커니즘과 표면 이온 이동성 간의 상관관계를 밝혀내는 기초 연구를 수행하고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
While SOFC perovskite oxide cathodes have been the subject of numerous studies, the critical factors governing their kinetic behavior have remained poorly understood. This has been due to a number of factors including the morphological complexity of the electrode and the electrode- electrolyte interface as well as the evolution of the surface chemistry with varying operating conditions. In this work, the surface chemical composition of dense thin film SrTi1−xFexO3-δelectrodes, with considerably
Abstract Identifying the important factors governing the oxygen reduction kinetics at solid oxide fuel cell cathodes is critical for enhanced performance, particularly at reduced temperatures. In this work, a model mixed conducting perovskite materials system, SrTi 1–x Fe x O 3–δ , is selected, offering the ability to systematically control both the levels of ionic and electronic conductivity as well as the energy band structure. This, in combination with considerably simplified electrode geomet
Supported metal catalysts represent one of the major milestones in heterogeneous catalysis. Such catalytic systems are feasible for use in a broad range of applications, including renewable energy devices, sensors, automotive emission control systems, and chemical reformers. The lifetimes of these catalytic platforms depend strongly on the stability of the supported nanoparticles. With this regard, nanoparticles synthesized <i>via</i> ex-solution process emphasize exceptional robustness as they
Concurrent studies of lattice strain, surface composition, and surface reactivity of a model perovskite oxide electrode provide a practical solution for effectively improving the durability of solid oxide electrochemical cell electrode.
A precise control of the size, density, and distribution of metal nanoparticles dispersed on functional oxide supports is critical for promoting catalytic activity and stability in renewable energy and catalysis devices. Here, we measure the growth kinetics of individual Co particles ex-solved on SrTi<sub>0.75</sub>Co<sub>0.25</sub>O<sub>3-δ</sub> polycrystalline thin films under a high vacuum, and at various temperatures and grain sizes using in situ transmission electron microscopy. The ex-sol
Schematics of water-mediated ex-solution and accordingly nano-engineered protonic ceramic fuel cell furnished with the water-mediated ex-solution on a cathode and H 2 ex-solution on an anode.
The key challenge that has limited the industrial utilization of nano-sized metal catalysts is their poor thermal stability and the resulting performance degradation. Here, we address this issue by designing a post-encapsulated composite structure in which individual Pt nanoparticles are surrounded by gas-permeable and catalytically active CeO2 shells. Positively charged surfactants on the nanoparticle surfaces are exploited to adsorb negatively charged Ce precursor complexes spontaneously, foll
Highly porous oxide structures are of significant importance for a wide variety of applications in fuel cells, chemical sensors, and catalysis, due to their high surface-to-volume ratio, gas permeability, and possible unique chemical or catalytic properties. Here we fabricated and characterized Sm0.2Ce0.8O1.9−δ films with highly porous and vertically oriented morphology as a high performance solid oxide fuel cell anode as well as a model system for exploring the impact of electrode architecture
An universal oxygen-electrode, compatible to both oxygen- and proton-conducting solid oxide electrochemical cells (O-SOCs and H-SOCs, respectively), as well as for electricity and hydrogen production purpose is showcased.
Abstract The electrocatalytic value of nanoparticles has attracted substantial attention in relation to energy conversion devices, including solid oxide fuel cells. Among various forms of analogs, ex‐solved metal nanoparticles originating from their parent oxides display strong particle‐substrate interactions and thus have the benefits of extended durability and of course enhanced catalytic activity. Inspired by recent advances, here, novel air‐electrode materials based on BaCoO 3–δ perovskites
(STF) model cathodes, with compositions and 0.5, prepared as dense films with a well-defined area and thickness on top of a single-crystal yttria stabilized zirconia substrate by pulsed layer deposition at were investigated by electrochemical impedance spectroscopy as a function of electrode geometry, temperature, and oxygen partial pressure. The STF cathode was observed to exhibit typical mixed ionic-electronic behavior with the electrode reaction occurring over the full electrode surface area
Schematic representation of possible oxygen electrochemical reduction pathways of self-assembled multi-phase cathodes with a synergistic ensemble effect.
