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In this work, the principles of environmentally friendly and efficient resource utilization have been implemented to move towards achieving carbon neutrality. Accordingly, the confined-space molecular-sieve properties of ZSM-5 zeolite were applied in cooperation with an external magnetic field with the aim to improve the catalytic LPG conversion and the selectivity of BTX (benzene, toluene, and xylenes) over Fe-Ga/ZSM-5 zeolites (0.5 wt.% Ga and 0.1 wt.% Fe). Effect of ZSM-5 particle sizes (0.6 μm, 1.1 μm, and 22.1 μm) on BTX yields and toluene to monoaromatic hydrocarbons were examined under magnetic field at a flux intensity of 28.7 mT in North-to-South direction and compared to those without magnetic field. The highest LPG conversion over Fe-Ga/ZSM-5 catalyst was found at the ZSM-5 particle size of 1.1 µm under external magnetic field, which is 1.2 times greater than that without magnetic field. The BTX yield was also increased by factors of 1.5 compared to those without magnetic field. The outstanding performance can be attributed to the synergistic effects between the external magnetic field and limited mass transfer within the confined-space zeolite. This combination facilitates and enhances the mass transfer ability and reaction performance of the reactant molecules. Consequently, this synergistic effect can lead to the development of green and sustainable innovations for chemical and separation processes in the future. [ABSTRACT FROM AUTHOR]

In this research, an external magnetic field has been employed to a catalytic packed bed reactor in order to improve the performance of copper and iron supported MCM-41 catalysts in carbon dioxide utilization through hydrogenation reaction. The result showed that magnetic field significantly improved carbon dioxide conversion at all reaction temperatures. The highest carbon dioxide conversion was obtained over 10(Cu)-10(Fe)/MCM-41 catalyst with magnetic flux density of −27.7 mT in north-to-south (N–S) direction which was 1.8 times higher than that of without magnetic field. In addition, the methanol space time yield was 1.5 times higher than that of without magnetic field and therefore, the lowest apparent activation energy (34.5 kJ/mol) was achieved. As a result, this integrated magnetic field-packed bed reactor could significantly reduce the operating temperature by 32.9 °C, 33.8 °C, and 57.7 °C over 10(Cu)/MCM-41, 10(Fe)/MCM-41, and 10(Fe)-10(Cu)/MCM-41 catalysts, respectively compared to those without magnetic field at the reaction temperature of 260 °C. With 10(Fe)-10(Cu)/MCM-41 catalyst, magnetic field could save electric energy costs of 2074–48,373 $/year with payback periods of 4.7–0.2 year at reaction temperatures of 180–260 °C, respectively based on CO 2 conversion of 100 kg/h. This outstanding performance could be attributed to the fact that magnetic field facilitated carbon dioxide adsorption on the magnetized catalyst surfaces. This led to the advantages of a heterogeneously catalyzed reaction including the enhancement of carbon dioxide utilization and methanol formation, the decrease of operating temperature, and the simultaneous decrease of carbon dioxide emission by means of energy-efficient process modification. [ABSTRACT FROM AUTHOR]

[Display omitted] • Magnetic field was first applied to catalytic reactor connected to in-situ TRXAS. • CO 2 conversion over xFe-yCu/MCM-41 was examined using Quadrupole Mass Spectroscopy. • Fe and Cu phase changes during reduction—reaction are observed by XANE technique. • Magnetic field plays key roles in stabilizing active FeO and Fe 3 O 4 during reaction. • Computational Chemistry implied selectivity to RWGS reaction under magnetic field. In this work, a systematic investigation of external magnetic field affecting metal phase transformation of Fe-Cu/MCM-41 catalysts both during activation and reaction, and their performances by means of CO 2 conversion and C 2 + C 3 hydrocarbons selectivity were for the first time examined in-situ using time-resolved X-ray absorption spectroscopy (TRXAS) and an online quadrupole mass spectrometer. The in-situ XANES result confirmed that FeO and Fe 3 O 4 are major active forms of the catalyst. With magnetic flux intensities of 28.91–58.59 mT, iron oxide phases, specifically Fe 3 O 4 and FeO, within the catalysts were stabilized and maintained. The CO 2 conversion was increased for 1.03 – 1.09 times, while the concentrations of C 2 + C 3 hydrocarbons were considerably improved by 24.03 – 35.37 times compared to those without magnetic field. The reaction steps of CO 2 hydrogenation were theoretically confirmed on the isolated catalysts using M06-L with the 6-31G(d,p) + LANL2DZ mixed basis set based on the results from LCF analysis. Fe 4 , Fe 4 O 4 , and Fe 2 Cu 2 clusters were used to represent the active species of pristine Fe and iron oxide (FeO) and bimetallic Fe-Cu catalyst, respectively. It was found that CO 2 hydrogenation could take place via the bimolecular route in which adsorbed CO 2 on the Fe center was hydrogenated by dissociative adsorption of H 2 on the Cu center—promoting chain growth probability of CO 2 to form C 2 + C 3 hydrocarbons due to the active iron oxides (Fe 3 O 4 and FeO) were maintained by magnetic field during the reaction. [ABSTRACT FROM AUTHOR]