Laboratory for Materials and Structures, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, 2268503, Japan.
Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1 Kouto, Sayo-gun, Hyogo, 6795198, Japan.
Adv Sci (Weinh). 2023 Jul;10(19):e2301876. doi: 10.1002/advs.202301876. Epub 2023 Apr 25.
Determination of a reaction pathway is an important issue for the optimization of reactions. However, reactions in solid-state compounds have remained poorly understood because of their complexity and technical limitations. Here, using state-of-the-art high-speed time-resolved synchrotron X-ray techniques, the topochemical solid-gas reduction mechanisms in layered perovskite Sr Fe O (from δ ∼ 0.4 to δ = 1.0), which is promising for an environmental catalyst material is revealed. Pristine Sr Fe O shows a gradual single-phase structural evolution during reduction, indicating that the reaction continuously proceeds through thermodynamically stable phases. In contrast, a nonequilibrium dynamically-disordered phase emerges a few seconds before a first-order transition during the reduction of a Pd-loaded sample. This drastic change in the reaction pathway can be explained by a change in the rate-determining step. The synchrotron X-ray technique can be applied to various solid-gas reactions and provides an opportunity for gaining a better understanding and optimizing reactions in solid-state compounds.
确定反应途径对于优化反应是一个重要的问题。然而，由于固态化合物的复杂性和技术限制，其反应仍然知之甚少。在这里，我们使用最先进的高速时间分辨同步加速器 X 射线技术，揭示了层状钙钛矿 SrFeO（从 δ∼0.4 到 δ=1.0）中拓扑化学反应的固-气还原机制，这是一种有前景的环境催化剂材料。原始 SrFeO 在还原过程中表现出逐渐的单相结构演化，表明反应通过热力学稳定相连续进行。相比之下，在负载 Pd 的样品还原过程中，在一级相变之前几秒钟会出现非平衡动态无序相。这种反应途径的剧烈变化可以通过速率决定步骤的变化来解释。同步加速器 X 射线技术可应用于各种固-气反应，为更好地理解和优化固态化合物中的反应提供了机会。
