QSTEM-based HAADF-STEM image analysis of Mo/V distribution in MoVTeTaO M1 phase and their correlations with surface reactivity

• Three probability models (Model 1–3) were advanced and investigated in this study based on metal distributions determined by the QSTEM-based HAADF-STEM image analysis.
• Model 1 was based on the probability of finding 1–2 V5+ cations in the proposed S3-S4-S4-S7-S7 catalytic center.
• Models 2 and 3 were based on the total V content and probability of finding more than 2 V cations in the S2-S4-S4-S7-S7 catalytic center, respectively.
• Correlations found for Model 3 emphasized the importance of multiple VOx sites present in the S2-S4-S4-S7-S7 catalytic center for catalytic reactivity in propane ammoxidation.

Three probability models (Model 1–3) were advanced and investigated in this study based on metal distributions determined by the QSTEM-based HAADF-STEM image analysis. The correlations between the Mo/V distributions in MoVTeTaO M1 phase catalysts and their catalytic behavior in propane ammoxidation were proposed for Model 1 (based on the probability of finding 1–2 V5+ cations in the proposed S3-S4-S4-S7-S7 catalytic center), Model 2 (based on the total V content in the S2-S4-S4-S7-S7 catalytic center), and Model 3 (based on the probability of finding more than 2 V cations in the S2-S4-S4-S7-S7 catalytic center). Model 1 suggested V5+ in S3 may activate propane. Model 2 and Model 3 emphasized the importance of total V content and multiple VOx sites in the S2-S4-S4-S7-S7 catalytic center for catalytic reactivity in propane ammoxidation, respectively.

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