(2an) CO2 Hydrogenation Reaction over Pd-Containing MWW Zeolite Catalyst

My research focuses on designing, synthesizing, processing, and characterizing zeolites for energy-efficient chemical transformation. Specifically, metal-containing zeolites with Lewis acidity for aldol condensation reaction, alkene epoxidation, and ketone ammoximation. Apart from batch reactor, I also devote myself into the liquid-phase fixed bed reactor set-up. Besides, I am also working on zeolite-supported metal catalysts for carbon dioxide reduction to address challenges in the net-zero goals in 2050. To obtain a highly active zeolite catalyst, we focused on the manipulation of the crystallization process. Specifically, the incorporation of metal species into the zeolitic framework and the hydrolysis and/or dissolution process of various starting materials. Through investigations of structural and chemical properties, we can create an ideal micro-environment within the porous material for the targeted reaction. Moreover, by using the in-situ optical techniques, we can analyze the intrinsic chemical properties giving us insights into active species and reaction mechanisms.

My main research goal is to understand the formation of zeolite catalysts and the significant factors leading to better catalytic performances based on theoretical and experimental studies. My future research plan is to approach the aspects of catalytic chemistry, environmental science, and reaction engineering to achieve a sustainable society.

Academic Research Experience:

2016 – 2017 B. S. in Chemical Engineering, The Ohio State University, Columbus, U.S.A

Supervisor: Prof. L. James Lee

Research Topic: Ultrasonic processing of MWCNT (multi-wall carbon nanotube) nanopaper reinforced polymeric nanocomposites.

2017 – 2018 M.S. in Applied Chemistry and Engineering, Tokyo Institute of Technology, Japan

Supervisor: Prof. Toshiyuki Yokoi

Research Topic: The synthesis of novel metal-containing zeolites with Lewis acid sites.

2018 – presence Ph.D. candidate in Applied Chemistry and Engineering, Tokyo Institute of Technology, Japan

Supervisor: Prof. Toshiyuki Yokoi

Research in Progress:

• Catalyst, Catalysis
• Microporous materials (in particular, zeolite) synthesis
• Design of zeolite materials with nanoscale dimensions and diverse pathways of crystallization
• Catalytic CO₂ hydrogenation
• Infrared spectroscopy for the study of phenomena occurring on catalyst surfaces

Professionality:

• Highly motivated chemist currently working in the field of heterogeneous catalysis with an additional background on synthesis of zeolite-based catalysts.
• Experienced in the synthesis of microporous materials (such a zeolite) and surface modification.
• Experienced in in-situ FTIR study and mechanistic study.
• Excellent teamwork and collaboration skills for managing different projects with the companies and guiding students.
• Presence of first-hand experience on using various analytical techniques such as XRD, SEM, XPS, GC (-TCO, -FID), FTIR, flow, batch reactors, Particle size analyzer.

Publications:

1. Sun, J., Zhao, Y., Yang, Z., Shen, J., Cabrera, E., Lertola, M. J., W., Zhang, D., Benatar, A. Castro, J. M., Wu, D., Lee, L. J. Highly stretchable and ultrathin nanopaper composites for epidermal strain sensors. Nanotechnology 29, 355304 (2018).
2. Zhao, Y., Cabrera, E., Lertola, M. J., W., Zhang, D., Benatar, A. Castro, J. M., Wu, D., Lee, L. J., Kuang, T., Yang, W., Lertola, M. J., Benatar, A., Castro, J. M., Lee, L, J. Ultrasonic processing of MWCNT nanopaper reinforced polymeric nanocomposites. Polymer 156, 85-94 (2018).
3. Elavarasan, M., Yang, W., Velmurugan, S., Chen, J.-N., Chang, Y.-T., Yang, T. C.-K., Yokoi, T. In-situ infrared investigation of m-TiO2/α-Fe2O3 photocatalysts and tracing of intermediates in photocatalytic hydrogenation of CO2 to methanol. Journal of CO2 Utilization 56, 101864 (2022).
4. Elavarasan, M., Yang, W., Velmurugan, S., Chen, J.-N., Yang, T. C.-K., Yokoi, T. Highly Efficient Photothermal Reduction of CO2 on Pd2Cu Dispersed TiO2 Photocatalyst and Operando DRIFT Spectroscopic Analysis of Reactive Intermediates. Nanomaterials 12, 332 (2022).

Abstract

The greenhouse gases, CO₂ in specific, have been overly produced and caused severe global warming. There is an urgent need for technologies to achieve a carbon-neutral society. To tackle this challenging task, the research group aims to develop a novel catalyst to serve CO₂, a kind of infamous greenhouse gas, as a sustainable carbon resource contributing to the green production of fine chemicals. Here in this work, the Pd-containing MWW zeolite catalyst has been deployed for the CO₂ hydrogenation reaction.

In previous studies, metallic photocatalysts were developed for CO₂ hydrogenation reactions and were found viable [1,2]. Knowing that the reaction performances of metal catalysts are significantly influenced by the particle sizes, and the number of active sites, the MWW zeolites impregnated with palladium were developed in this work. In this catalyst design, MWW framework limits the metal particles’ growth to form highly dispersed Pd nanoparticles across the zeolite support. Moreover, charge-balancing cations are also expecting to influence the CO2 adsorption efficiency.

A series of MCM-22 were synthesized as the support [3]. First, the as-calcined sample was synthesized through the reported method. Then the ammonium-type, proton-type, and sodium-type sample were obtained through ion exchange and calcination. Finally, the Pd was implemented into these zeolite support by incipient wet impregnation method [4]. From the XRD results, patterns of MCM-22 and Pd-containing MCM-22 are nearly identical and the peaks related to Pd metal particles are not significant. This indicates that either the Pd particles are nanosized or the peaks regarding to metal crystals are hinged under that of the zeolite support. The micrographs of SEM revealed the well-defined and regular porous microstructures. Furthermore, the elemental compositions measured from EDX agreed well with the ICP-AES results. In addition, the UV-vis spectra were implemented to investigate the metal species for each prepared sample.

Infrared spectroscopy is one of the most effective methods for characterizing heterogeneous catalysts. It allows us to investigate the molecular interaction between adsorbates and the catalyst statically and dynamically. The in situ FT-IR measurements can be probed by various chemicals giving us direct observations, including acid and base properties, metal coordinates, and reduction ability. This study also utilized this technique to provide spectroscopic evidence of the micro-environment across the heterogeneous catalysts. The synthesized samples undergo dark adsorption in the airtight gas cell from vacuum to different pressure gradients of CO₂ at ambient temperature, along with the transmission mode FTIR measurements. Another IR technique that will apply in this study is the diffuse reflectance infrared Fourier transform (DRIFT) measurements. The measurements will give us time-dependent observations of the CO₂ and carbonate species, revealing the possible kinetic mechanisms for transforming CO₂ into methanol and byproducts.

Reference

1. Elavarasan, M., Yang, W., Velmurugan, S., Chen, J. N., Chang, Y. T., Yang, T. C. K., & Yokoi, T. (2022). In-situ infrared investigation of m-TiO2/α-Fe2O3 photocatalysts and tracing of intermediates in photocatalytic hydrogenation of CO2 to methanol. Journal of CO2 Utilization, 56, 101864.
2. Elavarasan, M., Yang, W., Velmurugan, S., Chen, J. N., Yang, T. C. K., & Yokoi, T. (2022). Highly Efficient Photothermal Reduction of CO2 on Pd2Cu Dispersed TiO2 Photocatalyst and Operando DRIFT Spectroscopic Analysis of Reactive Intermediates. Nanomaterials, 12(3), 332.
3. Wang, Y., Yokoi, T., Namba, S., Kondo, J. N., & Tatsumi, T. (2016). Improvement of catalytic performance of MCM-22 in the cracking of n-hexane by controlling the acidic property. Journal of Catalysis, 333, 17-28.
4. Yasuda, S., Osuga, R., Kunitake, Y., Kato, K., Fukuoka, A., Kobayashi, H., ... & Yokoi, T. (2020). Zeolite-supported ultra-small nickel as catalyst for selective oxidation of methane to syngas. Communications Chemistry, 3(1), 1-8.