Promoting effects of CO2 on dehydrogenation of propane over a SiO2-supported Cr2O3 catalyst

Enhancing catalytic activity of Cr2O3 in CO2-assisted propane dehydrogenation with effective dopant engineering: a DFT-based microkinetic simulation

Using CO2 as a mild oxidizing agent in propane dehydrogenation (PDH) presents an attractive pathway for the generation of propene while maintaining high selectivity. Cr2O3 is one of the most important catalysts used for the CO2-assisted PDH process. In this study, the doping of Cr2O3 with single atoms such as Ge, Ir, Ni, Sn, Zn, and Zr was used for the PDH process. The introduction of dopants significantly modifies the electronic structure of pristine Cr2O3, leading to substantial alterations in its catalytic capabilities. The dehydrogenation reactions were explored both in the absence and presence of CO2. The addition of CO2 introduces two distinct pathways for PDH. On physisorbed CO2 surfaces, Ge and Ni-Cr2O3 enhance dehydrogenation. On the dissociated surface, the CO* and O* species actively participate in the reaction. All doped surfaces exhibit low energy barriers for dehydrogenation, except undoped Cr2O3 on dissociated CO2 surfaces. The Ni-Cr2O3 surface emerges as the most active surface for dehydrogenation of propane in all scenarios. Additionally, the catalytic surface is re-oxidized through H2 release, and doped surfaces facilitate coke removal via the reverse Boudouard reaction more efficiently than undoped Cr2O3. Microkinetics simulations identify the removal of the first H-atom as the rate-determining step. CO2 reduces the apparent activation energy, directly impacting C3H8 conversion and C3H6 formation. This study offers a decisive description of Cr2O3 modification for the CO2-assisted PDH process.

Metallic Catalysts for Oxidative Dehydrogenation of Propane Using CO2

The oxidative dehydrogenation of propane using CO₂ (CO₂ -ODP) is a promising technique for realizing high-yield propylene production and CO₂ usage. Developing a highly efficient catalyst for CO₂ -ODP is essential and beneficial to the chemical industry and for realizing net-zero emissions. Many studies have investigated metal oxide-based catalysts, revealing that rapid deactivation and low selectivity remain limiting factors for their industrial applications. In recent years, metallic nanoparticle catalysts have become increasingly attractive due to their unique properties. Therefore, we summarize the performance of metal-based catalysts in CO₂ -ODP reactions by considering catalyst design concepts, different mechanisms in the reaction process, and the role of CO₂ .

A critical evaluation of the catalytic role of CO2 in propane dehydrogenation catalyzed by chromium oxide from a DFT-based microkinetic simulation

Propane dehydrogenation under CO₂ is an important catalytic route to obtain propene with a good balance between selectivity and stability. However, a precise description of the catalytic role of CO₂ in propane dehydrogenation is still absent. In this work, we focus on the elucidation of the role of CO₂ by using DFT-based microkinetic simulation. The influence of CO₂ is categorized as direct and indirect effects. It was found that the chemisorbed CO₂ can directly abstract hydrogen from propane and propyl with a comparable barrier to the counterpart at the surface oxygen site. On the other hand, the dissociation of CO₂ yields active surface species of CO* and O* which are actively involved in the removal of surface hydroxyls. It is found that the TOFs of both propane conversion and propene formation are significantly increased with the presence of CO₂, which is explained by the reduced apparent activation energy. The primary hydrogen abstraction is identified to be the most influential step from the DRC analysis. The main effects of CO₂ are concluded to be removing hydrogen and restoring oxygen vacancies from reaction pathway analysis.

Recent Advances in the Applications of Mesoporous Silica in Heterogenous Catalysis

Mesoporous silica is a class of silica material with a large specific surface area, high specific pore volume and meso-sized pores. These properties make mesoporous silica a good choice of...

Ru-Promoted CO2 activation for oxidative dehydrogenation of propane over chromium oxide catalyst

A volcano-shape propylene production rate trend as Ru loading on CrO_x catalysts increases for CO₂-assisted C₃H₈ dehydrogenation reaction.

Combining CO2 reduction with propane oxidative dehydrogenation over bimetallic catalysts

The inherent variability and insufficiencies in the co-production of propylene from steam crackers has raised concerns regarding the global propylene production gap and has directed industry to develop more on-purpose propylene technologies. The oxidative dehydrogenation of propane by CO₂ (CO₂-ODHP) can potentially fill this gap while consuming a greenhouse gas. Non-precious FeNi and precious NiPt catalysts supported on CeO₂ have been identified as promising catalysts for CO₂-ODHP and dry reforming, respectively, in flow reactor studies conducted at 823 K. In-situ X-ray absorption spectroscopy measurements revealed the oxidation states of metals under reaction conditions and density functional theory calculations were utilized to identify the most favorable reaction pathways over the two types of catalysts.

The oxidative dehydrogenation of propane by CO₂ (CO₂-ODHP) can potentially fill the gap of propylene production while consuming a greenhouse gas. Here, the authors identify non-precious FeNi and precious NiPt catalysts supported on CeO₂ as promising catalysts for CO₂-ODHP and dry reforming, respectively, in flow reactor studies.

Impregnation vs. coprecipitation dispersion of Cr over TiO2 and ZrO2 used as active and stable nanocatalysts in oxidative dehydrogenation of ethane to ethylene by carbon dioxide

The catalytic performance of Cr/ZrO₂ and Cr/TiO₂ nanocatalysts, prepared by coprecipitation and impregnation methods, was examined in oxidative dehydrogenation of ethane to ethylene using CO₂ as an oxidant.

Partial oxidation of propane with CO2 on Ru doped catalysts

The catalytic activity and stability of Ru doped CeO₂ and Ru doped ZrO₂ are investigated and compared for the partial oxidation of propane using carbon dioxide as an oxidant.

Preparation, Characterization, and Oxidative Dehydrogenation of C3H8 with CO2 of V-Cr/SBA-15/Al2O3/FeCrAl Metal Monolithic Catalysts

A series of V-Cr/SBA-15/Al2O3/FeCrAlmetal monolithic catalystswithV content of 10wt% and Cr contents from 0 to 12.5wt% were prepared. The structure of the catalysts was characterized using XRD, XPS and TPR techniques. The catalytic activity for oxidative dehydrogenation (ODH) of propane with CO2was evaluated. The results indicate that the mesoporous structure of SBA-15 was retained after vanadium and chromium incorporation and the vanadium species were well dispersed. The V-Cr/SBA-15/Al2O3/FeCrAl catalyst with 10wt%V and 10 wt% Cr exhibited the best activity with a propane conversion of 49.9% and a propylene selectivity of 86.5% at 650 °C.