A density functional theory study on how γ-Al₂O₃ - Boehmite transformation affects carbon evolution during...

Gamma-alumina (γ-Al₂O₃), one of the most common materials, is commercially used in many catalytic applications, including the active catalyst and support. However, the problem of fast deactivation makes the utilization of the γ-Al₂O₃ challenging. This work elucidates the mechanism of coke formation consisting of coke deposition and evolution on γ-Al₂O₃(110) surfaces in differential conditions, including; clean and hydroxylation γ-Al₂O₃(110) in terms of partial and fully hydroxylation of OH/γ-Al₂O₃(110) and AlOOH(010), respectively. We demonstrated that the γ-Al₂O₃(110) surface is proper for atomic coke deposition and dimerization in the initial state, where the presence of OH species promotes the coke evolution to higher coke, C_n (where n ≥ 3). Also, the higher coke formation thermodynamically preferred the cyclic form to the aliphatic one. The electron transfer from substrates to adsorbed coke illustrates the role of the electron donor of catalyst surfaces corresponding to the electron acceptor of adsorbed cokes.