Roles of niobium in the dehydrogenation of propane to propylene over a Pt/Nb-modified Al₂O₃ catalyst

Abstract

The application of Pt-based catalyst in propane dehydrogenation (PDH) was restricted by low propylene selectivity, metal sintering and carbon deposition. It is reported that the performance of catalyst is strongly...

Highly Efficient Oxidation of Propane at Low Temperature over a Pt-Based Catalyst by Optimization Support

“…The bands at 1469 and 1573 cm –1 belonged to the ν s (COO – ) and ν as (COO – ) modes of carboxylate species, respectively, indicating that propane could react with the active oxygen species on the Pt/Nb 2 O 5 catalyst surface . Besides, the bands at 1652, 1620, and 1448 cm –1 were attributed to the CC group, the ν as (CH 2 CH–O – ) mode of enolate species, and allyl species, respectively, clearly implying that an acrylate pathway occurred on the Pt/Nb 2 O 5 catalyst in propane oxidation. , It was reported that Pt catalysts on niobium oxide possess excellent performance in the dehydrogenation of propane, which can render the initial reaction process involving an oxidative dehydrogenation of propane into propene, rather than an overoxidation into propionate and oxidative addition into isopropoxide species. , When the feed gas was switched into a C 3 H 8 and O 2 mixture, the bands related to enolate, CC groups, and allyl species disappeared quickly. In contrast, the peaks at 1544, 1452, and 1425 cm –1 belonged to monodentate carbonate (m-CO 3 2– ), carboxylate (RCOO – ), and bicarbonate (HCO 3 – ) species, respectively (Figure S20B).…”

“…34 Besides, the bands at 1652, 1620, and 1448 cm −1 were attributed to the C�C group, the ν as (CH 2 �CH− O − ) mode of enolate species, and allyl species, respectively, clearly implying that an acrylate pathway occurred on the Pt/ Nb 2 O 5 catalyst in propane oxidation. 9,35 It was reported that Pt catalysts on niobium oxide possess excellent performance in the dehydrogenation of propane, which can render the initial reaction process involving an oxidative dehydrogenation of propane into propene, 21 rather than an overoxidation into propionate and oxidative addition into isopropoxide species. 9,11 When the feed gas was switched into a C 3 H 8 and O 2 mixture, the bands related to enolate, C�C groups, and allyl species disappeared quickly.…”

“…19,20 Similar results have been reported in which Pd on metal oxide supports (TiO 2 and Nb 2 O 5 ) with high Δ f H M-O θ was barely oxidized, resulting in stable metallic Pd particles. 20 Furthermore, Pt catalysts on niobium oxide possess superior performance in the dehydrogenation of propane, 21 which may result in different reaction routines for propane oxidation on supported Pt catalysts. 11,13 Therefore, niobium oxides are more promising for constructing metallic Pt active sites for C 3 H 8 oxidation.…”

Recent progress in catalytic dehydrogenation of propane over Pt-based catalysts

“…Alumina is the most commonly used support for PDH due to its high surface area, thermal stability and mechanical strength. 75–78 The surface area, acid–base properties, and coordination structure of Al 2 O 3 have been demonstrated to have a significant influence on the catalytic performance of Pt-based catalysts. Accordingly, adjusting the morphology and surface properties of Al 2 O 3 can have an important effect on the resulting Pt-based catalysts.…”

“…Alumina is the most commonly used support for PDH due to its high surface area, thermal stability and mechanical strength. [75][76][77][78] The surface area, acid-base properties, and coordination The interaction between Pt and the support has an important influence on the catalytic stability. It was found that unsaturated pentacoordinate Al 3+ centers present on the (100) facets of the g-Al 2 O 3 surface can anchor Pt.…”