Enriching Unsaturated Coordination for High-Performance Chromium Oxide Catalysts

Abstract

Chromium oxide catalysts are a type of industrial catalyst that is commonly utilized in heterogeneous catalytic processes. Their outstanding catalytic activity is accomplished through the efficient interception of unsaturated coordination and favored surface aggregation. However, the increase of surficial unsaturated coordination and its structural characterization continues to challenge the limitations of chemical synthesis and atomic decoding of nanocatalysts. In this study, a thermal shock method was employed to intercept a significant number of unsaturated coordination and high-valence chromium species in CrO_x-based nanocatalysts. The transformation of nearest-neighbor symmetry from octahedral to tetrahedral was discovered to be centered on the surface of the nanoparticle through the atomic recognition of chromium species using the pair distribution function (PDF) and reverse Monte Carlo (RMC). The catalytic efficacy of symbolic catalytic reactions, such as the dehydrogenation of propane, toluene oxidation, and benzyl alcohol oxidation, is enhanced by the precise synthesis of the surficial active sites. Our results demonstrate a convenient chemical synthesis method that preserves the metastable structure of oxide catalysts under thermal shock. The atomic structural understanding also offers an intuitional experimental model for the study of reaction mechanisms.