Effect of a Ce Promoter on Nonoxidative Dehydrogenation of Propane over the Commercial Cr/Al₂O₃ Catalyst

Abstract

The Cr/Al2O3 catalyst is a typical commercial catalyst system that has been widely applied for propane dehydrogenation (PDH). Appreciable improvement in catalytic performance of this catalyst is of importance regarding its further applications, but investigations of the interaction between Ce and Cr species and the effects of Ce modification on the dispersion and distribution of the active Cr phases have seldom been concerned in the previous works. In this work, M/Al2O3 (M: Cr, Ce, and Ce–Cr) catalysts were synthesized and the Ce-modified catalyst exhibited enhanced activity. It was shown that modification of Ce on the Cr/Al2O3 catalyst decreased the amount of inactive isolated Cr­(VI) sites. Meanwhile, the increased amount of oxygen vacancy was observed over the Ce–Cr/Al2O3 catalyst, which promoted the interaction between Ce and Cr species. The above results can be confirmed by the characterization results of X-ray diffraction, UV–vis, H2-temperature-programmed reduction, X-ray photoelectron spectroscopy, and Raman spectroscopy, which provide meaningful information for improving catalytic performance of the commercial Cr/Al2O3 catalyst during PDH.

Promoting Propane Dehydrogenation with CO2 over the PtFe Bimetallic Catalyst by Eliminating the Non-selective Fe(0) Phase

“…Propylene is an important feedstock for the production of value-added chemicals such as polypropylene and propylene oxide, and its global demand is increasing with an annual growth rate of ∼5%. − Among several propylene production technologies, catalytic propane dehydrogenation (PDH) has attracted much attention due to its unique advantages of cleanness, high efficiency, and high atomic utilization. − Generally, the commercially available PDH catalysts can be divided into metal oxides, such as CrO x , − and noble metal Pt-based catalysts. − With the low toxicity and high activity, further development of new efficient Pt-based PDH catalysts is a vital direction while full of challenges.…”

One-step conversion of lignin-derived alkylphenols to light arenes by co-breaking of C–O and C–C bonds

“…8 that two kinds of lattice spacing (0.245 and 0.21 nm) were simultaneously detected on the 15% Cr 2 O 3 /Al 2 O 3 catalyst, respectively corresponding to Cr 2 O 3 and Al 2 O 3 . 35 The distribution of Cr on the surface of the Cr 2 O 3 /Al 2 O 3 was determined by scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy (STEM/EDX). The Cr mapping of 15% Cr 2 O 3 /Al 2 O 3 before the reaction confirmed a very uniform distribution of Cr on the catalyst surface (Fig.…”

Advanced design and development of catalysts in propane dehydrogenation

“…Zhang and co-workers reported a Ce-modified Cr/Al 2 O 3 catalyst with outstanding activity, which demonstrated that the enhanced stability was attributed to the decreased content of isolated inactive Cr( vi ) in the Ce-doped Cr/Al 2 O 3 catalyst. 90 They further indicated that the increased amounts of oxygen vacancy could bring about strong interactions between Ce and Cr. In the research by Han et al , the characterization and DFT calculation results revealed the unsaturated coordination of adjacent Zr sites acting as the dominant active component in Cr 20 Zr 80 /SiO 2 with low loading contents of CrZrO x constituents.…”