近日，中国科学技术大学林岳团队报道了反应性金属-载体相互作用的单原子层诱导反向扩散途径。相关论文于2025年11月27日发表在《美国化学会志》上。

反应性金属-载体相互作用（RMSI）在调控负载型金属催化剂的组分、构型与电子结构方面展现出巨大潜力。

尽管现有实验与理论研究均认为RMSI通过金属原子从载体向负载纳米颗粒一步扩散实现，研究组发现Pt/TiO₂体系中存在相反的扩散路径：负载纳米颗粒中的铂原子先于载体钛元素迁移，在载体表面铺展形成单原子层铂结构。通过原位加热像差校正高角环形暗场扫描透射电镜（HAADF-STEM）观测发现，该单原子层铂可通过电子转移削弱Ti-O键，促进表面氧释放及后续钛原子向铂迁移，最终实现金属间化合物（IMC）的形成。这种以单原子层铂为中间态的机制阐明了降低载体内部金属原子扩散能垒以保障IMC有效形成的策略。所制备的Pt₃Ti金属间化合物具有d带中心下移的富电子铂活性位点，在电催化氢氧化反应中展现出卓越的抗CO毒化性能。

附：英文原文

Title: Single-Atom-Layer-Induced Reversed Diffusion Pathway of Reactive Metal–Support Interaction

Author: Xiao Han, Shuwen Niu, Geng Wu, Xiaolin Tai, Haohui Hu, Fanfei Sun, Haiwei Liang, Xun Hong, Yue Lin

Issue&Volume: November 27, 2025

Abstract: Reactive metal–support interaction (RMSI) exhibits great potential in modulating the component, configuration, and electronic structure of supported metal catalysts. While current experimental and theoretical studies both regard that RMSI occurs through one-step diffusion of metal atoms from the support toward the supported nanoparticles, our study reveals a reversed diffusion pathway during RMSI, where Pt atoms in the supported nanoparticles spread out on the support to form a single-atom-layer Pt before the incorporation of Ti elements from the support in Pt/TiO2. The single-atom-layer Pt, identified by in situ heating aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), could weaken Ti–O bonds through electron transfer, facilitate surface oxygen release and following Ti atom migration toward Pt, ultimately enabling intermetallic compound (IMC) formation. The elucidated formation mechanism with a single-atom-layer Pt offers guidance for reducing the diffusion energy barrier of metal atoms within the support to ensure the effective formation of an IMC. The resulting Pt3Ti IMC, featuring electron-rich Pt active sites with a downshifted d-band center, exhibits exceptional resistance to CO poisoning during electrocatalytic hydrogen oxidation.

DOI: 10.1021/jacs.5c12151

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.5c12151