Performance of Non-stoichiometric Perovskite Catalyst (A_xCrO_3−δ, A: La, Pr, Nd) for Dehydrogenation of Propane Under Steam Condition

Abstract: The aim of this study was to clarify the effect of the non-stoichiometry in the A_xCrO_3−δ (A: La, Pr, Nd, 0.90 ≤ x ≤ 1.05) perovskite-type oxide on the dehydrogenation performance of propane using steam (DHP-S). The slight change in the molar ratio of the A-site (=La, Pr, Nd) to the B-site cation (=Cr) from the stoichiometric composition (A/B = 1) significantly affected the dehydrogenation performance. For the La-based catalyst, the La_xCrO_3−δ catalyst with 0.90 ≤ x ≤ 0.97 displayed a relatively high activity, while the catalyst with 0.97 < x ≤ 1.05 did not show any activity for the DHP-S. The perovskite catalyst having the A-site defect presented a high performance for the DHP-S regardless of the types of A-site cation. The Nd_0.95CrO_3−δ catalyst displayed the highest performance among the A-site defective perovskite catalysts. The Nd_0.95CrO_3−δ catalyst also showed a superior stability compared to the CrO_x/γ-Al₂O₃ catalyst. Based on an XPS measurement, the reduction–oxidation (redox) property was improved by changing the Nd/Cr molar ratio from the stoichiometric composition (Nd/Cr = 1) to a non-stoichiometric composition. Such a good redox property would produce a high performance for the DHP-S. Graphical Abstract: [Figure not available: see fulltext.]