Synthesis of a Crystalline Orthorhombic Mo–V–Cu Oxide for Selective Oxidation of Acrolein

A crystalline orthorhombic Mo–V–Cu oxide (MoVCuO) was successfully obtained by hydrothermal synthesis using a methylammonium cation as a structure-directing agent, and catalytic role of Cu for selective oxidation of acrolein to acrylic acid (AA) was evaluated using crystalline Mo3VOx (MoVO) as a comparison. Cu was located at the corner of a heptagonal channel micropore in the MoVO structure with a square planar configuration. The introduction of Cu substantially improved AA selectivity up to 98% from 93% obtained over the MoVO catalyst. The introduction of Cu would moderate the activation of molecular oxygen at the heptagonal channel site and prevent side reactions such as oxidative C–C scission to form COx and acetic acid, resulting in the enhancement of AA selectivity.