Formulation and processing of dual functional Adsorbent/Catalyst structured monoliths using an additively manufactured contactor for direct Capture/Conversion of CO2 with cogeneration of ethylene

Abstract

• Formulation and processing of dual functional adsorbent/catalyst monoliths. • Implementation of DFM monoliths into direct air capture/conversion of CO 2 . • Metal screening of 3D-printed DFM monoliths in ODHE in a single bed process. • 65.2% CO 2 conversion and 98% C 2 H 4 selectivity was obtained over V 2 O 5 -CaO/ZSM-5. Utilizing CO 2 as a mild oxidant for oxidative dehydrogenation of ethane (ODHE) is an attractive way of recycling this greenhouse contaminant. Typically, CO 2 capture and conversion processes are performed in separate beds, however, combining these processes into one bed incurs advantages of lower thermal gradient and reduced energy costs. This study formulated the first generation of structured dual-functional materials (DFMs) by directly 3D printing metal-oxide-CaO/ZSM-5 inks into monolithic contactors. Specifically, we 3D-printed monoliths with V, Ga, Ni, or Ti dopants to perform metal screening and determine which metal generates the best structured DFM for combined CO 2 capture and utilization in ODHE. The samples were vigorously characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), N 2 physisorption, NH 3 -temperature programmed desorption (NH 3 -TPD), H 2 -temperature programmed reduction (H 2 -TPR), energy dispersive spectroscopy (EDS), and Pyridine Fourier Transform Infrared Spectroscopy (Py-FTIR). Their CO 2 capture/ODHE performances were assessed with CO 2 adsorption at 600 °C and ODHE of 25 mL/min 7% C 2 H 6 at 700 °C. The combined adsorption/catalysis experiments indicated that the best performance was observed in V-CaO/ZSM-5 which achieved a staggeringly high CO 2 capture (5.4 mmol/g), 65.2% CO 2 conversion, 36.5% C 2 H 6 conversion, 98% C 2 H 4 selectivity, and 35.8% C 2 H 4 yield as well as zero thermal cracking after 40 min-on-stream. This performance exceeded that of any previously reported material for combined CO 2 capture and ODHE utilization, indicating this novel printing method can generate DFMs with exceptional potential for combined CO 2 capture and utilization processes.