Density functional theory investigation of acetylene dehydrogenation on metal exchanged ZSM-5 clusters for initial step of carbon nanotube production

• Catalytic C–H bond activation of acetylene is theoretically investigated.
• Several metal-exchanged ZSM-5 clusters are used as catalysts.
• M- and M-O-M-ZSM-5 (M = Co, Fe, Ni, and V) cluster structures are used.
• M-O-M-ZSM-5 (M = Ni, Co) clusters have lower activation barriers.

Adsorption and dehydrogenation of acetylene have been theoretically studied on [M(SiH3)4AlO4] and [(M-(μ-O)-M)Si6Al2O9H14] (where M = Co, Fe, Ni, and V) clusters representing ZSM-5 zeolite. Adsorption and dehydrogenation of acetylene were performed as an initial step of carbon nanotube synthesis by using Density Functional Theory calculations with utilization of B3LYP formalism. If activities of different clusters are compared, M-(μ-O)-M-ZSM5 clusters show better performance than the M-ZSM5 clusters for acetylene activation. Activation barriers of Ni-(μ-O)-Ni-ZSM5 and Co-(μ-O)-Co-ZSM5 clusters are lower than those of other ZSM-5 clusters. It can be therefore concluded that Ni-(μ-O)-Ni-ZSM5 and Co-(μ-O)-Co-ZSM5 catalysts can be used for H removal from acetylene as an initial step for carbon nanotube production.

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