Understanding structure and property phenomena, bettering the world

Richard C. Alkire Chair Hong Yang describes chemical engineering as combining concepts from chemistry with engineering principles to develop processes for chemical and energy products.

“Both the conceptual and quantitative sides of the brain have to work together to achieve the engineering goal; I guess that’s another way to put it,” he said with an easy laugh. “You can achieve amazing things in this profession.”

Yang said that the career paths and fields available to chemical engineers are many and varied: energy, pharmaceuticals, mico-electronic companies, modeling for Wall Street and financial firms, consulting companies—or teaching and research.

He has chosen the latter. Yang’s work centers on the design and synthesis of metal and metal oxide nanostructures for a range of catalytic applications, including in hydrogen-powered fuel cells and low-temperature electrolyzers for water splitting.

In middle school, Yang was charmed by the transformation he witnessed during an experiment where sugar was carbonized by sulfuric acid, producing a rising column of black carbon. At that moment, he wanted to understand and manipulate these phenomena. 

This pursuit, along with his aptitude for chemistry and physics—and ambition—plucked Yang from Northern China’s coal region and brought him to one of the world’s most populous cities, Beijing, where he studied at the prestigious Tsinghua University.

Tsinghua’s recruiters assigned Yang to the physical chemistry degree program based on his high scores in physics and chemistry on the national entrance tests. Luckily, at that time, he could choose his department: chemical engineering.

Yang went on to earn his master’s degree at the University of Victoria and doctorate at the University of Toronto before completing postdoctoral research at Harvard University.

“There were a few hurdles for me during the time I grew up in China, and back then, the education and research environment was completely different from today’s China— you probably cannot imagine,” he said.

Indeed, Yang has overcome obstacles and had a few “lucky” breaks along the way. 

He was among the first students from his hometown area to be selected to attend a highly selective middle school, which he commuted to daily by riding in the back of a truck. He tested into one of the top universities in the country and was among the first to graduate from the chemistry department that was established halfway through his degree. To pursue his studies abroad, he passed the GRE TOEFL exam using any reading material he could get his hands on, including an aviation trade magazine.

However, the study of phenomena in the chemical sciences is at the heart of Yang's story. For his bachelor’s degree thesis, he worked on drug delivery and reducing the toxicity of a cancer drug by encapsulating it in vesicles made of fat molecules called lipids. He studied the separation of lipids from eggs as a proxy for this process.

“This was my introduction to research for the function of materials,” Yang said. “I am very curious about ‘why it happened.’ My curiosity and simple quest for function in materials are continuously led in the direction of applied fundamental research.”

Yang went to the University of Toronto to further his graduate studies and to earn a doctorate. There, he worked under the direction of Geoffrey A. Ozin, known for his seminal work in nanochemistry. Yang was attracted to a new subject that he had not explored before that point in his studies. His research focused on a self-assembly approach to make two- to five-nanometer crystalline porous materials—something still difficult to achieve today—called ordered mesopores that could maximize catalysis and the chemical separations of important chemicals, such as lipids and proteins. The results of his first three years of research appeared in three Nature papers, including a featured cover of the magazine. 

“The idea is that you can maximize the utilization of those materials at a nanometer scale,” Yang said. “I'm extremely interested in making nanostructure materials, whether it’s a particle or something that supports particles. We are now making functional materials as catalysts—because we cannot wait for millennia for reactions to happen.” 

When he began his doctoral studies, Yang wanted to work as an industrial researcher in materials development, but Ozin inspired him to choose a different path in academia.

During his postgraduate studies, Yang transitioned from understanding nanomaterials’ anatomy to application. Working with professor George Whitesides at Harvard, Yang worked on the development of uniform nanomaterials that could be assembled into functional materials.

During his postgraduate studies, Yang transitioned from understanding nanomaterials’ anatomy to application. Working with professor George Whitesides at Harvard, Yang worked on the development of uniform nanomaterials that could be assembled into functional materials.

When Yang began his faculty career at the University of Rochester, he started a collaboration with General Motors’ Hydrogen Fuel Cell Center, also in the Rochester area. He realized the octahedral-shaped nanomaterials made of platinum, iron, and cobalt alloys he was developing were ideal for hydrogen fuel cell cathode development.

“That’s how I repositioned our nanomaterials project for several applications, but all in sustainability development,” Yang said. “What makes these nanomaterials unique is that we try to control not only for the size of the particle but also for the shape. Now, as we try to push performance higher and higher, it turns out which surface is exposed makes a huge difference.”

His team published a series of papers that showed that they could control the platinum-nickel and other so-called low platinum group metal electrocatalysts with the right geometry.

In 2012, Yang joined the faculty at the University of Illinois, drawn by the university’s research infrastructure and collegial colleagues.

Today he is known for his research efforts related to sustainability; he is creating nanomaterials for electrolyzers and hydrogen fuel cells. His group is also developing a new type of electrocatalyst by using single atoms as the active site to reduce the amount of active material needed for a reaction.

“I am still dealing with nanostructured materials and how we can optimize them to get the best performance,” Yang said. “That is fascinating to me, and there’s a lot of unsolved issues there. How can you arrange all these atoms in a way that we like them to behave? We cannot work against thermodynamics, but we can play so many different tricks at the nanometer scale to improve the properties.”

In 2015, Yang was invested as the Richard C. Alkire Chair, established in honor of emeritus professor Richard Alkire who joined the department in 1969.

At Yang’s investiture ceremony, Alkire said, “The research of professor Yang represents a superb example of this next-generation of engineering—the manipulation of atomic-scale distributions of elements on catalytic surfaces to optimize their catalytic activity and stability for reducing oxygen—one of the most important chemical reactions of them all.”

In a relatively new line of research for Yang’s lab, they are working on the missing pieces needed to complete fuel cell technology: the production of hydrogen. While it is easy to produce hydrogen in a water electrolyzer, it is tricky to produce oxygen at the other electrode to match the high production rate of hydrogen, which is needed to complete the reaction in splitting water molecules. His team is working on creating stable, low-cost, complex metal oxide catalysts with specific surface and bulk features and structures to produce hydrogen from water.

"My curiosity often drives me to know how and why things happen and how we can improve the process," Yang said. “If I need new knowledge, I get to work on a subject and learn what I need to know. Working in chemical engineering allows me to think critically and practically in tackling new problems. When no obvious solutions are present, I do not shy away from exploring an engineering solution, and we do it based on what we know.”

From developing workhorse catalysts to realizing educational opportunities in a difficult era, Yang has a unique ability to manipulate and understand phenomena to achieve the desired outcome—all for the world's benefit.