정우철 교수

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

Catalytic supremacy of Pt-single atoms achieved by CeO_x–TiO₂interfaces.

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

Abstract Electrochemical water splitting represents a promising technology for green hydrogen production. To design advanced electrocatalysts, it is crucial to identify their active sites and interpret the relationship between their structures and performance. Materials extensively studied as electrocatalysts include noble‐metal‐based (e.g., Ru, Ir, and Pt) and non‐noble‐metal‐based (e.g., 3d transition metals) compounds. Recently, advancements in characterization techniques and theoretical calc

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.

Abstract Tuning material properties by modulation of the arrangement of atoms is a fundamental and effective strategy in materials science. Structurally long‐range ordered materials are increasingly finding utility for electrocatalytic applications. Such ordered structures can achieve unique functions that increase the electrocatalytic activity compared to corresponding electrocatalysts with a disordered structure. Effective strategies for designing high‐performance electrocatalysts based on str

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.

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_0.75Co_0.25O_3-δ polycrystalline thin films under a high vacuum, and at various temperatures and grain sizes using in situ transmission electron microscopy. The ex-sol

Supported metal nanoparticles hold great promise for many fields, including catalysis and renewable energy. Here we report a novel methodology for the in situ growth of architecturally tailored, regenerative metal nanocatalysts that is applicable to a wide range of materials. The main idea underlying this strategy is to selectively diffuse catalytically active metals along the grain boundaries of host oxides and then to reduce the diffused metallic species to form nanoclusters. As a case study,

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.

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