Adsorption-Enhanced Bifunctional Catalysts for In Situ CO₂ Capture and Utilization in Propylene Production: A Proof-Of-Concept Study

Abstract

In this study, cooperative bifunctional materials (BFMs)�composed of combined adsorbent and catalyst materials� are synthesized and processed through additive manufacturing by 3D printing adsorbent/catalyst monoliths with a CaO adsorbent phase balanced against an M@ZSM-5 (M = In, Ce, Cr, or Mo oxide) heterogeneous catalyst phase. The adsorbent/catalyst monoliths were characterized using NH 3 -TPD, H 2 -TPR, N 2 physisorption, X-ray photoelectron spectroscopy, X-ray diffraction, pyridine-Fourier transform infrared spectroscopy, C 3 H 8 -diffuse reflectance infrared Fourier transform spectroscopy, and energydispersive spectroscopy. Their performances were evaluated for combined CO 2 capture and propane dehydrogenation at 600−700 °C. These experiments revealed that a reaction temperature of 600 °C generates the best performance for all samples due to the shift toward thermal cracking at higher temperatures. Moreover, 600 °C was usable for both CO 2 adsorption and catalysis, so the materials reported here could truly perform both adsorption and catalysis isothermally. Of the materials, CaO-Mo@ZSM-5 displayed the best performance, generating 20.4% propylene yield, 20% propane conversion, 75% CO 2 conversion, and 5.4 mmol/g CO 2 capture capacity at 600 °C. The stability of this sample was then assessed across ten adsorption/reaction cycles at T = 600 °C, where its propane conversion, CO 2 conversion, and propylene yield varied by less than 5% across the entirety of the experiment. Overall, this work accomplishes three key goals: it (i) expands the concept of BFM materials to a previously unexplored reaction for direct CO 2 capture from air (direct air capture) or flue gas, and subsequent utilization, (ii) provides a facile way of structuring BFM materials into practical contactors, and (iii) allows adsorption and catalysis to occur at the same temperature with high cyclic stability within a single bed.

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

“…The estimated BET surface area from these isotherms was 1207 m 2 /g, whereas the micro- and mesopore volumes were found to be 0.41 and 0.18 cm 3 /g, respectively. These results are in agreement with the literature data. , The XRD pattern of MOF-74 in Figure c displayed two characteristic diffraction peaks ranging from 7° to 13°, which resembled those in the simulated spectrum from the single-crystal mode. The SEM image in Figure d further confirmed the successful formation of the MOF-74 crystals with uniform polyhedral crystalline phases, which resembled those reported in the literature for this MOF.…”

Synergistic promotions between CO2 capture and in-situ conversion on Ni-CaO composite catalyst

“…Then, the synergistic promotion effects between the CO 2 capture and in situ conversion may result in both high and stable CO 2 capture capacity and conversion efficiency 9 , 10 . Currently, the reported DFMs in most iCCC processes are CaO-based composites largely due to its excellent theoretical CO 2 capacity (17.8 mmol g −1 ) at high temperatures 11 , 12 . Instead of the calcination regeneration at above 900 °C in the traditional Calcium looping (CaL) 13 , 14 , the in situ conversion of captured CO 2 may significantly lower the regeneration temperature and thus overcome the bottleneck problems of high energy penalties and CaO sintering.…”

Cold Temperature Direct Air CO2 Capture with Amine-Loaded Metal–Organic Framework Monoliths

“…The Rezaei group explored a series of ink formulations for 3D printing based on water, clay, poly (vinyl alcohol) (PVA), and porous adsorbents . This formulation has been used to fabricate monoliths of zeolites and MOFs for not only gas sorption but also heterogeneous catalysis. ,,, For example, Lawson et al used this ink system to prepare MIL-101­(Cr) monoliths and impregnate amines in these monoliths for CO 2 removal in an enclosed environment . More recently, this ink formulation was adopted to fabricate monoliths containing two types of nanoparticles: Fe 3 O 4 and Ni-MOF-74 .…”