Direct Synthesis of Ethylene and Hydrogen from CO₂ and Ethane over a Bifunctional Structured CaO/Cr₂O₃-V₂O₅/ZSM-5 Adsorbent/Catalyst Monolith

Abstract

In this study, we synthesized bifunctional adsorbent/catalyst materials (BFMs) consisting of a CaO adsorbent admixed with Cr2O3-V2O5/ZSM-5 catalysts. The obtained BFMs were further formulated, processed, and shaped through additive manufacturing (3D printing) method. The physical and chemical properties of structured CaO/Cr2O3-V2O5/ZSM-5 adsorbent/catalyst monoliths were thoroughly characterized and evaluated. The effects of operating conditions including reaction temperature, ethane composition, and space velocity on single-bed CO2 capture and selective formation of ethylene and hydrogen were systematically investigated. The adsorption–reaction experiments revealed that Cr-based BFMs, in particular, CaO/Cr4/ZSM-5 monoliths undergo the oxidative dehydrogenation pathway with high C2H4 selectivity, whereas increasing the content of V leads to enhanced catalytic activity for the reforming pathway to produce hydrogen. The best adsorption/catalyst BFM performance was observed for CaO/Cr1-V3/ZSM-5, which was balanced between the two reaction pathways and resulted in 1.72 mmol/g CO2 capture capacity, 63.95% CO2 conversion, 22.4% C2H6 conversion, 42% C2H4 selectivity, and 45% syngas (31% hydrogen) selectivity. Furthermore, the cyclic test results revealed excellent catalytic stability across the initial two cycles over CaO/Cr1-V3/ZSM-5 monolith, highlighting the synergetic effect of bimetallic catalyst constituents on maintaining high catalytic durability. This novel formulation and processing method can pave the way toward formulation of various structured BFM monoliths with cooperative CO2 adsorptive removal and catalytic performance for one-pot CO2 capture–utilization and simultaneous production of light olefins and hydrogen.

Influence of Interfering Ions and Adsorption Temperature on Radioactive Iodine Removal Efficiency and Stability of Ni-MOF-74 and Zr-UiO-66

“…The IPD model fitting was performed by maximizing the R value for each curve, which were in the range of 0.88–0.99%. As evident, for both MOF-74 and UiO-66 samples, the adsorption data were fitted poorly to the single straight line, implying that the intraparticle diffusion was not the rate-limiting step, rather, the intraparticle diffusion model fitting was found to be mostly multilinear, indicating that adsorption kinetics was controlled by multiple processes including (i) external surface adsorption, (ii) intraparticle diffusion, and (iii) final equilibrium steps. The k id estimated from this nonlinear analysis was found to be in the ranges of 0.66–1.90 and 0.34–1.04 mg/g·min 1/2 for MOF-74 and UiO-66, respectively (see Table ).…”

Recent progress in the development of catalysts for propane dehydrogenation in the presence of CO2

“…Given that the dehydrogenation activity of VO x -based catalysts was found to be intimately related to the reducibility of surface VO x , which increases with a decrease in the VO xsupport interactions, the effects of the support matrix on the molecular structure of VO x have been investigated. 85,[127][128][129][130][131] In the study by Shan, et al, 123 they found that VO x supported on ZrO x possessed the highest CO 2 -OPDH activity and was the easiest to be reduced compared to VO x supported on Al 2 O 3 , MgO and SiO 2 . Similarly, Nakagawa et al 120 loaded 5% V on different supports and performed CO 2 -OPDH at 550 °C, and found that the activity of the catalysts followed the order of VO x supported on diamond oxide > Al 2 O 3 > activated carbon > SiO 2 , which is consistent with their reducibility orders.…”

Magnetic-Induced Swing Adsorption over Iron Oxide/13X: Effects of Particle Size and Oxide Phase on Sorbent Regeneration in Ethylene/Ethane Separation

“…The global chemical industry produces over 170 million tons of ethylene (C 2 H 4 ) each year, typically by thermal decomposition or steam reforming of ethane (C 2 H 6 ). − To purify the produced C 2 H 4 , downstream cryogenic distillation is required to remove small amounts of co-existing C 2 H 6 . − Considering how energy-intensive this separation process is, significant efforts have been made to replace it with non-thermal methods, such as membrane separation or adsorption. − In particular, C 2 H 4 /C 2 H 6 separation via adsorption over nanoporous materials has been touted as a promising technology to improve energy efficiency of this process. , However, adsorptive separation of light olefins/paraffins still remains in its infancy despite significant advances that have been made in sorbents design and discovery over the past few decades.…”