Recently, Professor Deng Huiqiu's team from the School of Physics and Microelectronics at Hunan University, in collaboration with Professor Jeffrey Greeley and Dr. Zhenhua Zeng from Purdue University in the United States, and Professor Marc Koper's team from Leiden University in the Netherlands, has confirmed the specificity of surface stress-driven reactivity.
Published under the title "Site-specific reactivity of stepped Pt surfaces driven by stress release," this research achievement appears in the prestigious international journal Nature. The School of Physics and Microelectronics at Hunan University is the first affiliation listed, with Dr. Guangdong Liu from Hunan University and Dr. Arthur J. Shih from Leiden University as co-first authors. Professor Deng Huiqiu from Hunan University is listed as the third author, while Professor Jeffrey Greeley from Purdue University and Dr. Zhenhua Zeng are the corresponding authors.
Identifying active sites and maximizing their efficacy is at the core of catalysis research. In the prediction of catalytic activity, traditional categorization of active sites can lead to errors of several orders of magnitude, resulting in unclear configurations of active sites and severely constraining the rational design of catalytic materials.
Under the computational resources provided by the National Supercomputing Changsha Center and the Rosen Center for Advanced Computing at Purdue University, Professor Deng Huiqiu's team collaborated with the team led by Jeffrey Greeley and Zeng Zhenhua at Purdue University to conduct systematic research on the electrochemical oxygen reduction reaction (ORR) on platinum metal terrace surfaces. Using first-principles density functional theory calculations, they investigated the surface stress and strain of terrace surfaces with widths ranging from 1 to 10 nanometers, and found that step-like defects could release significant surface stress, driving atomic relaxation across non-uniform strain fields spanning several nanometers in width. The compressive strain could reach up to 5.5%, leading to different electronic structures and reactivity of platform surface atoms with the same local coordination, resulting in enhanced ORR activity specificity. For example, the ORR activity of atoms on the edges of the steps was 50 times higher than that of atoms in the middle of the terrace. This discovery explains the fundamental reason for the significant errors produced by the classical discrete active site model in predicting catalytic activity, unraveling the long-standing mystery surrounding the sensitivity of active sites and the structure of the oxygen reduction reaction.
The Relationship Between Surface Stress Release and Surface Strain in Pt(hkl) Surfaces
To validate the specificity of surface stress release in generating heterogeneous strain fields and atomic site reactivity for tuning catalytic performance, they further deposited impurity gold atoms at the step edges of platinum terraces on the surface, utilizing external stress to drive stress release and regulate catalytic performance. Professor Marc Koper's team experimentally confirmed the theoretical predictions in this work, affirming that manipulating surface stress and strain fields is an effective strategy for regulating chemically sensitive reactions on strained surfaces. This study provides a new perspective on understanding catalytic active sites and the design of heterogeneous catalysts, enabling more precise prediction and computational design of heterogeneous catalysts.
Dr. Liu Guangdong, who obtained his master's and doctoral degrees in physics from our university in 2018 and 2022 respectively, is currently continuing his postdoctoral research here under the supervision of Professor Deng Huiqiu. Professor Deng Huiqiu's research group is actively involved in computational simulations and design work in the fields of nuclear energy and new energy materials. They are responsible for several key research and development projects under national programs and have received significant funding support from the National Natural Science Foundation of China for their joint fund key projects.
