Grain Boundary-Rich Bi2WO6 Catalysts Enable Synergistic Activation of Molecular and Lattice Oxygen for Oxidative Dehydrogenation of 1-Butene

The mechanistic understanding of the simultaneous activation of molecular oxygen (O₂) and surface lattice oxygen (O^2–) at grain boundaries (GBs) remains elusive. Herein, we report that GB-rich Bi₂WO₆ catalysts, engineered via controlled GB modulation, enable the dual activation of both the O₂ and lattice oxygen species. Specifically, GBs facilitate the formation of oxygen vacancies and enhance the electron-donating ability of the Bi and W centers, thereby promoting O₂ activation. Simultaneously, GB-induced lattice strain activates surface lattice oxygen, with the density of GBs positively correlating with its reactivity. However, an excessively high GB density can adversely affect catalytic performance, underscoring the need for an optimal GB configuration. Notably, the synergistic action between peroxo-like species (O₂^2–) and surface lattice oxygen (O^2–) at the GBs enables highly efficient oxidative dehydrogenation (ODH) of 1-butene to 1,3-butadiene. Compared with the GB-deficient counterpart, the GB-rich Bi₂WO₆ catalyst exhibits markedly enhanced activity and selectivity. This work provides critical insights into GB-mediated dual oxygen activation and advances the understanding of structure–activity relationships in oxidative heterogeneous catalysis.