Wu Zhi-Peng, Shan Shiyao, Zang Shuang-Quan, Zhong Chuan-Jian
Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States.
Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou 450001, P. R. China.
Acc Chem Res. 2020 Dec 15;53(12):2913-2924. doi: 10.1021/acs.accounts.0c00564. Epub 2020 Nov 10.
ConspectusMultimetallic nanomaterials containing noble metals (NM) and non-noble 3d-transition metals (3d-TMs) exhibit unique catalytic properties as a result of the synergistic combination of NMs and 3d-TMs in the nanostructure. The exploration of such a synergy depends heavily on the understanding of the atomic-scale structural details of NMs and 3d-TMs in the nanomaterials. This has attracted a great deal of recent interest in the field of catalysis science, especially concerning the core-shell and alloy nanostructures. A rarely asked question of fundamental significance is how the core-shell and alloy structural arrangements of atoms in the multimetallic nanomaterials dynamically change under reaction conditions, including reaction temperature, surface adsorbate, chemical environment, applied electrochemical potential, etc. The dynamic evolution of the core-shell/alloy structures under the reaction conditions plays a crucial role in the catalytic performance of the multimetallic nanocatalysts.This Account focuses on the dynamic structure characteristics for several different types of composition-tunable alloy and core-shell nanomaterials, including phase-segregated, elemental-enriched, dynamically evolved, and structurally different core-shell structures. In addition to outlining core-shell/alloy structure formation via processes such as seed-mediated growth, thermochemical calcination, adsorbate-induced evolution, chemical dealloying, underpotential deposition/galvanic displacement, etc., this Account will highlight the progress in understanding the dynamic core-shell/alloy structures under chemical or catalytic reaction conditions, which has become an important focal point of the research fronts in catalysis and electrocatalysis. The employment of advanced techniques, especially / synchrotron high-energy X-ray diffraction and pair distribution function analyses, has provided significant insights into the dynamic evolution processes of NM/3d-TM nanocatalysts under electrocatalytic or fuel cell operating conditions. Examples will highlight Pt- or Pd-based nanoparticles and nanowires alloyed with various 3d-TMs with a focus on their structural evolution under reaction conditions. While the dynamic process is complex, the ability to gain an insight into the evolution of core-shell and alloy structures under the catalytic reaction condition is essential for advancing the design of multimetallic nanocatalysts. This Account serves as a springboard from fundamental understanding of the core-shell and alloy structural dynamics to the various applications of nanostructured catalysts/electrocatalysts, especially in the fronts of energy and environmental sustainability.
综述
含有贵金属（NM）和非贵金属3d过渡金属（3d-TM）的多金属纳米材料由于纳米结构中NM和3d-TM的协同组合而表现出独特的催化性能。这种协同作用的探索在很大程度上依赖于对纳米材料中NM和3d-TM原子尺度结构细节的理解。这在催化科学领域引起了近期的广泛关注，特别是关于核壳和合金纳米结构。一个具有根本重要性但很少被问到的问题是，多金属纳米材料中原子的核壳和合金结构排列在反应条件下，包括反应温度、表面吸附物、化学环境、外加电化学势等，是如何动态变化的。反应条件下核壳/合金结构的动态演变在多金属纳米催化剂的催化性能中起着关键作用。
本综述聚焦于几种不同类型的成分可调合金和核壳纳米材料的动态结构特征，包括相分离、元素富集、动态演变以及结构不同的核壳结构。除了概述通过种子介导生长、热化学煅烧、吸附物诱导演变、化学脱合金、欠电位沉积/电偶置换等过程形成核壳/合金结构外，本综述还将突出在化学或催化反应条件下对动态核壳/合金结构理解方面的进展，这已成为催化和电催化研究前沿的一个重要焦点。先进技术的应用，特别是同步加速器高能X射线衍射和对分布函数分析，为理解NM/3d-TM纳米催化剂在电催化或燃料电池运行条件下的动态演变过程提供了重要见解。实例将突出与各种3d-TM合金化的基于Pt或Pd的纳米颗粒和纳米线，重点关注它们在反应条件下的结构演变。虽然动态过程很复杂，但深入了解催化反应条件下核壳和合金结构的演变对于推进多金属纳米催化剂的设计至关重要。本综述作为一个跳板，从对核壳和合金结构动力学的基本理解到纳米结构催化剂/电催化剂的各种应用，特别是在能源和环境可持续性前沿。
