Vapor-phase self-assembly for generating thermally stable single-atom catalysts

Summary

Preparation of thermally stable metal single-atom catalysts (SACs) is a challenge in heterogeneous catalysis, especially on conventional supports that provide a weak metal-support interaction. In this work, we report that a modified support MgAl₂O₄ can stabilize Pt single atoms by a mechanism of vapor-phase self-assembly in a high-temperature treatment (800°C, air). The experimental results on the formation mechanism and the structure are validated by DFT and ab initio molecular dynamics simulations. We infer that stable triangular K₃O₃ structures help stabilize Pt single atoms at high temperatures in oxidizing conditions, exhibiting excellent reactivity for methane oxidation. The obtained Pt/K/MgAl₂O₄ SAC presents excellent stability in methane oxidation after steam treatment at elevated temperatures, whereas the Pt/MgAl₂O₄ nanocatalyst suffers from rapid deactivation due to Pt nanoparticle growth. This work paves the way for preparing thermally stable and highly active SACs using conventional high-surface-area supports, despite the weak metal-support interaction.