Enhancing activation and stability of core-shell CuZn catalyst by ZnOx oxygen vacancies for methanol steam reforming

Abstract

Oxygen vacancies have been proved to be a key to catalysts’ performance in methanol steam reforming (MSR). In this work, a series of CuZn/γ-Al2O3/Al catalysts with different ZnOx oxygen vacancy content were designed to further understand effects of oxygen vacancies on the enhancement of activation and durability. Through numerical investigation and kinetic analysis, it was found that the migration energy of ZnOx on Cu was reduced by oxygen vacancies, leading to a more uniform core-shell structure and accelerated activation. By analysing the changes in valence and particle sizes of Cu species during different stages of the reaction, it was speculated that more uniform core-shell structure and Cu+ resisted Cu agglomeration, leading to a longer lifespan. Ultimately, by analyzing reduction performance and particle evolution of Cu NPs, a ‘delayed release effect’ was discovered.