Beyond platinum? The cutting edge of solid catalyst research: Shaping the invisible world
Dr. Junya OHYAMA
Associate Professor, Faculty of Advanced Science and Technology
Solid catalysts are essential to various technologies that support our daily lives, including purifying automobile exhaust gases, manufacturing plastic products, and producing fuel cells. Associate Professor Junya Ohyama is pioneering research to replace the expensive platinum catalysis used in fuel cells with new catalysts boasting performance, aiming to pave the way to a sustainable energy future.
Solid Catalysts: The Unsung Heroes Supporting Daily Life
First, please tell us about the research theme you are currently working on.
My research theme is “solid catalysts.” A catalyst is a substance that facilitates chemical reactions without undergoing any permanent change itself, thereby helping reactions proceed more efficiently. In fact, many of the products we use in our daily lives would not exist without catalysts.Take automobile exhaust, for example. Burning gasoline or diesel fuel produces harmful nitrogen oxides (NOx). Releasing these directly into the atmosphere harms human health and causes environmental problems like acid rain. Catalysts are therefore used to convert NOx into harmless nitrogen. They also play a key role in transforming petroleum into plastics during the manufacturing process. Catalysts are truly the unsung heroes of modern technology, although they are usually invisible, they are actively at work in countless areas of our society.
I hear you presented research on catalysts used in fuel cells this time. What was the focus of your study?
Fuel cells are devices that generate electricity through a reaction between hydrogen and oxygen. However, simply placing hydrogen and oxygen in the same container does not cause the reaction to proceed on its own. By using a catalyst, the reaction can be accelerated, enabling the extraction of electrical energy.Fuel cells have great potential for applications such as vehicles and residential power generation, but the biggest challenge has been the catalyst. Currently, large amounts of platinum are used, yet platinum is both rare and extremely expensive. This has become a major obstacle to the widespread adoption of fuel cells.
Since joining Kumamoto University, I have been actively pursuing research on catalysts that can serve as alternatives to platinum. Recently, I have focused particularly on cobalt complexes. Cobalt is a relatively inexpensive and readily available element, and with the appropriate structural design, it is expected to exhibit performance comparable to platinum. Of course, platinum performs exceptionally well, and surpassing it outright is not easy. However, I believe that creating catalysts that completely eliminate the need for platinum—or significantly reduce the amount required, would be highly meaningful for an energy-dependent society like ours.
Photo: A high-durability cobalt catalyst developed by Associate Professor Ohyama’s research group
Challenging the visualization of the nano world! A new world comes into view!
Photo: Associate Professor Ohyama’s 3D-printed atomic-arrangement model of a palladium nanoparticle catalyst
Why did you begin this research?
What drew me to catalyst research was the thrill of those moments when “the invisible becomes visible.” During my student days, I worked with enzyme-mimetic catalysts, and I vividly remember the thrill of being able to infer molecular motion. My current research on solid catalysts grew naturally from that early experience, and the drive to “peer into the invisible world” continues to motivate me today. In catalyst research, understanding “what the structure looks like” is crucial. Yet the atomic-level world is so small that it has long been considered “invisible.” I am taking on the challenge of ‘visualizing’ this “hidden world.”One such effort is the 3D visualization of nanoparticles. By analyzing data obtained from electron microscopes and synchrotron X-rays, we reconstruct the atomic arrangements as three-dimensional models. These reconstructed models are then produced using 3D printers. Being able to physically hold and examine them revealed that catalyst structures, once imagined only through simple schematic diagrams, are in fact distorted or possess unexpected shapes.
For example, in cobalt complexes where nitrogen atoms surround cobalt atoms in a square shape, whether the cobalt atom “slightly protrudes” or “fits neatly inside” the nitrogen square has a significantly effect on the catalyst's durability. Similarly, in palladium nanoparticles, one shape excels at activating hydrogen, while another excels at burning methane. Even a tiny “bump” at the single-atom level are drastically alters the catalyst's behavior. It truly is a world where “form determines function.” A difference as small as the position of a single atom can determine whether a catalyst can ultimately be used in society. This depth and subtlety are what make catalyst research so profoundly fascinating.
Seeing the structure take on a visible form really deepens understanding, doesn’t it?
Yes, absolutely. When students and I assemble the 3D model together, they can physically feel why “this particular shape leads to higher performance.” Science often deals with invisible worlds, but being able to “touch” a model makes the concepts much easier to grasp. These insights, when combined with computer simulations, lead to even more powerful catalyst design. If we can predict in advance that “this atomic arrangement will produce high performance,” we can verify it efficiently through experiments. By going back and forth between experimental work and theoretical modeling, we try to bring next-generation materials design into reality.Continuing to ask “Why?” leads to research that contributes to society.
What kind of research would you like to pursue in the future?
The ultimate goal of my research is to contribute to a sustainable society. The world is now making significant strides toward achieving carbon neutrality. For example, we generate hydrogen by splitting water using electricity from solar power, then utilize that hydrogen in fuel cells. Efficient and affordable catalysts are essential to supporting this type of circular, renewable energy system.What fascinates me most about catalyst research is the opportunity to “reveal a world no one has ever seen before.” By understanding how atoms are arranged, we can freely control a catalyst’s performance. Every day, as I conduct research with students, questioning “Is this really true?”, we uncover new and unexpected findings. In the lab, I always ask, “What do you think?” and strive to create an environment where students can challenge themselves from their own perspectives. The shared excitement of discovering something new and saying, “Isn't this fascinating!?” is one of the greatest joys of research.
Please give a message for everyone!
Science is not about memorizing the right answers; it begins with persistently asking “Why?” Our research for alternatives to platinum grew from simple questions like “Why is platinum so exceptional?” and “Is there truly no alternative?” Even small doubts can grow into major challenges, ultimately leading to discoveries that change the future. Cherish your own “Why?” and take that first step forward.
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