From the Development of Zeolite Catalysts to Achieving Carbon Neutrality

I work on developing zeolite catalysts for the methanol to olefins (MTO) reaction. These are used in processes that produce light olefins, such as ethylene (C2) and propylene (C3). These light olefins are the building blocks of chemical products, and our goal is to use zeolites to catalyze the MTO reaction and produce these raw materials from methanol, which is itself synthesized from carbon dioxide and hydrogen with water as the raw material.

Zeolites are porous, crystalline materials created from highly ordered arrangements of mainly silicon (Si), aluminum (Al), and oxygen (O) atoms. A unique quality of zeolites is that their crystal structure has nanosized spaces that allow the passage of molecules. Currently, zeolites are used in a wide range of applications, such as the conversion of petrochemical products, the purification of automobile exhaust gases, and the removal of radioactive materials related to the Fukushima nuclear accident. They are also used in building materials and home appliances for their adsorptive properties.

One project I am currently working on is developing technology to create the raw materials for plastics from CO₂. This research uses zeolite catalysts to produce the raw materials for plastic and other chemical production building blocks from methanol, which itself has been generated from carbon dioxide and solar hydrogen, which is hydrogen produced from sunlight and water. This research will lead to the development of innovative chemical production processes that do not rely on fossil resources.

My research focuses on the synthesis and practical application of zeolites and other nano-space materials crucial for enabling these catalytic processes. Zeolites offer a real solution to a range of environmental, energy, and resource-based issues that currently affect us on a global scale and are essential for achieving Sustainable Development Goals (SDGs).

Zeolite synthesis and properties allow for a diverse range of framework structures. Calculations show that over 2.6 million zeolite structures are possible, though only around 260 of these have been synthesized in experiments to date, and of these, only around 10 are used in industry. While zeolites have the potential to become a key material in achieving a carbon-neutral society, much is still unknown about the mechanism of zeolite crystallization, and the atomic arrangement of zeolites remains unclear. Novel zeolite development, determining how zeolite structures change during crystallization, and understanding zeolite structures at an atomic level are all important aspects of research aimed at improving the functionality and expanding the range of applications of these materials. When crystallizing zeolites, it is important to determine the presence and content of aluminum and other metallic elements. We use Shimadzu inductively coupled plasma (ICP) emission spectrometers and atomic absorption (AA) spectrophotometers to achieve this. Essentially, my research involves creating zeolites that will serve as “ideal catalysts” with a spatial structure, elemental composition, and local structure tailored to specific applications.

I am also developing zeolite catalysts for technology to produce biofuels from underutilized biomass resources. These include empty fruit bunches (EFB) that remain after palm oil extraction and are produced in massive amounts in Southeast Asia, the straw and husk that remain after rice production, and the biomass created during sugar cane production. We use Shimadzu gas chromatograph (GC), gas chromatograph mass spectrometer (GC-MS), and high-performance liquid chromatograph (HPLC) systems to conduct qualitative and quantitative analysis of catalytic reactions involving zeolite catalysts.

Since 2024, with support from SATREPS (Science and Technology Research Partnership for Sustainable Development), I have embarked on internationally partnered research between Japan and developing countries that will apply zeolite catalyst technology to address global issues and improve scientific and technological standards. As part of this research, we are developing a catalyst-based process that can be used to produce chemical products in a biorefinery with the goal of adding value to waste biomass generated in Thailand’s agricultural sector.

I also plan to work with iPEACE223 Inc., an Institute of Science Tokyo start-up. The company aims to help achieve carbon neutrality in the energy and chemical sectors by shifting raw materials from fossil-based to biomass-based sources. In this project, we are working to develop an ethylene to propylene (ETP) reaction that will use a zeolite catalyst to produce propylene directly from ethylene. We are also working to further improve zeolite catalysts.

After using Shimadzu GC and ICP systems for many years, I believe the systems are easy to use, and the software and other aspects of the systems are easy for researchers to understand. I also like how specialized the systems are in terms of their support for customization for specific applications, such as automated gas chromatography. However, as the number of foreign students increases, it would be helpful if software, instruction manuals, and maintenance support were available in English and Chinese.

We determine the position of atoms in zeolite catalysts by electron microscopy. However, the crystalline structures of zeolite catalysts are easily damaged by the electron beams used in electron microscopes, and this can prevent us from gaining an accurate understanding of zeolite structures. My hope is that Shimadzu can develop a new analytical technique that provides information on zeolite structure and the mechanism of crystallization at the atomic level in a non-destructive manner.

Professor Yokoi’s laboratory uses several Shimadzu products, including the GC-2014 and ICPE-9000. We are grateful for the valuable insights provided in this interview.