Hydrothermally prepared chromia-alumina (xCr/Al₂O₃) catalysts with hierarchical structure for propane dehydrogenation

Abstract

Propane dehydrogenation was investigated over a series of chromia-alumina (xCr/Al2O3) catalysts containing 2.5–10 wt% chromium (Cr), synthesizedviaa hydrothermal synthesis method.

State-of-the-art catalysts for direct dehydrogenation of propane to propylene

“…Supported CrOx are one of the most efficient catalysts for alkane dehydrogenation that have been studied for several decades [17,[28][29][30][31][32][33][34][35][36][37]. Owing to the low price and high catalytic activity, CrOx-based catalysts have been commercially utilized in Catofin craft [21,23,24].…”

“…A series of metal oxides (such as Al2O3, SiO2, and ZrO2) have been studied as supports of CrOx catalysts [18,24,[28][29][30][31][32][33][34][35][36][37][38][39]. In these CrOx-based catalysts, the supports play an important role in determining the dispersion (such as isolated Cr n+ , oligomeric Cr n+ , and crystallite CrOx species), states (such as Cr 6+ , Cr 5+ , Cr 3+ , and Cr 2+ ), structure, and electronic properties of the Cr species, thus affecting their catalytic activity, stability, and anti-coking capability in the PDH process.…”

“…Improving the porosity of CrOx-based catalysts is a good way of improving their performance in PDH. It was reported that CrOx species supported on mesoporous Al2O3 exhibited enhanced activity in the PDH process due to the presence of many mesopores and highly dispersed Cr species [29]. A series of highly ordered mesoporous Cr/Al2O3 and Cr-Zr-O catalysts with narrow pore size distributions were synthesized by nanocasting method using CMK-3 as a hard template [30,41], and the resulting ordered mesoporous CrOx/Al2O3 and Cr-Zr-O catalysts exhibited enhanced resistances to deactivation in PDH, compared to those of CrOx catalysts supported on commercial Al2O3 and bulk ZrO2.…”

Rod-shaped porous alumina-supported Cr2O3 catalyst with low acidity for propane dehydrogenation

“…Propylene is one of the most important building blocks in petrochemical industry [1,2], with a global production capacity of 127 million metric tons per year. Currently, the industrial process for propylene production is mainly based on the steam cracking and fluid catalytic cracking (FCC) of naphtha, light diesel, and other oil byproducts [2,3], which inevitably involves extensive energy consumption and significant emission of CO2 [1,4]. Compared with the thermal or catalytic cracking, direct catalytic propane dehydrogenation (PDH) to obtain propylene is a more economical and environmentally friendly route [5] and has been commercialized by UOP and ABB Lummus in the 1990s [6].…”

“…The catalyst support not only serves as a scaffold but also provides a complex microenvironment, which is a key factor in determining the catalytic function [3]. The catalyst support should be thermally stable enough to maintain the morphology of the catalyst, in addition to providing an open structure for the catalyst to allow easy access to the reactants and preventing the blockage of the pore by coke [4,11].…”