Engineering Specific Mo–O Bond Stretching to Activate Lattice Oxygen in V-Doped Bi2MoO6 for Enhanced Oxidative Dehydrogenation of 1-Butene

Structural distortion has been demonstrated to regulate lattice oxygen activity, but its precise regulation has always been a thorny problem, especially for the oxidative dehydrogenation of hydrocarbons. Herein, by synthesizing a series of V-doped Bi 2 MoO 6 catalysts, mechanistic insight into the effect of structural distortion on the catalytic activity of oxidative dehydrogenation of 1-butene was provided. Comprehensive characterizations and kinetics tests revealed that the V-doped Bi 2 MoO 6 -induced active lattice oxygen initiates 1-butene activation by abstracting the C–H bond, which is a rate-determining step. Combined with density functional theory results, an overwhelming effect of the bond length between Mo and apical oxygen atom in the MoO 6 octahedron on lattice oxygen activation and butadiene formation pathway was proposed. The stretching Mo–O apical bond elicited by V doping enhances the abstraction of hydrogen and accelerates the redox cycle. The sample with a 5% V content possesses the maximum Mo–O apical bond length, enabling superior catalytic performance at an 87.6% 1,3-butadiene yield.