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Tuning Adsorption and Catalytic Properties of α-Cr₂O₃ and ZnO in Propane Dehydrogenation by Creating Oxygen Vacancy and Doping Single Pt Atom: A Comparative First-Principles Study

Chang, Qing-Yu, Yin, Qiang, Ma, Fang, Zhu, Yi-An, Sui, Zhi-Jun, Zhou, Xing-Gui, Chen, De, Yuan, Wei-Kang
Industrial & engineering chemistry process design and development 2019 v.58 no.24 pp. 10199-10209
Lewis acids, Lewis bases, active sites, adsorption, catalytic activity, chromium, dehydrogenation, density functional theory, electrons, ions, oxidation, oxygen, platinum, propane, zinc oxide
Density functional theory calculations have been performed to examine the different catalytic behaviors of α-Cr₂O₃ and ZnO in propane dehydrogenation. On ZnO(101̅0), adsorption of a Lewis acid at the metal site can be strengthened with the coadsorption of a Lewis base at an adjacent oxygen site. In contrast, this Lewis acid–base interaction does not occur on Cr₂O₃(0001) because the Cr ions can exist in a lower oxidation state and thus withdraw electrons from the base, which limits the ability of the oxide to transfer electrons to the acid. Both creating oxygen vacancy and doping single Pt atom on ZnO(101̅0) may give rise to a weaker acid–base interaction and hence to a change in the active site. Microkinetic analysis indicates formation of oxygen vacancy has a positive and negative effect on the reactivity of α-Cr₂O₃ and ZnO, respectively, whereas doping a Pt single atom invariably promotes the dehydrogenation reaction.