Redox Treatment of Orthorhombic Mo₂₉V₁₁O₁₁₂ and Relationships between Crystal Structure, Microporosity and Catalytic Performance for Selective Oxidation of Ethane

Abstract

Redox treatments of an orthorhombic Mo29V11O112 catalyst (MoVO) were conducted and its crystal structure, microporosity, and catalytic activity were investigated. TPR and TG revealed that MoVO evolved two kinds of lattice oxygen (α-oxygen and β-oxygen) from the structure by reduction treatment. In the early stage of reduction, α-oxygen was evolved from the structure, causing expansion of the micropore channel. With further reduction, the atoms in the pentagonal [Mo6O21]6– unit moved toward the micropore channel, resulting in a decrease in micropore size. Expansion of the micropore drastically increased catalytic activity for selective oxidation of ethane, but the activity was decreased by a reduction in the micropore channel size. Strong relationships were found between crystal structure, microporosity, and catalytic activity for selective oxidation of ethane.