Ga-doped spinel-typed Co-Al catalysts for CO2-assisted ethane dehydrogenation

Abstract

A series of Ga-doped spinel-typed Co-Al catalysts were prepared via one-step evaporation-induced self-assembly (EISA) method. These catalysts present promising catalytic performance for CO₂-assisted ethane dehydrogenation, which can be ascribed to the conjunction effect of cobalt and gallium species. The incorporation of Ga into the structure of Co-Al spinel has been recognized for enhancing CO₂ conversion via reverse water-gas shift reaction, leading to a favorable equilibrium shift towards ethylene, along with an improved catalyst stability as a result of coexisting Boudouard reaction. Through X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS), NH₃ and CO₂ temperature-programmed desorption (TPD) characterizations, coordinatively unsaturated Co²⁺ and Ga³⁺ cations were identified as collaborative catalytic active sites, with gallium species taking the prominent role. These sites were closely associated with the formation of acid-base pairs on the catalyst surface, which were crucial for the adsorption and activation of the reactants.