Making green hydrogen in class

Green hydrogen is generating real enthusiasm on an international scale. In Quebec, the government has launched a national strategy to promote its production. In several sectors of activity, hydrogen could one day constitute a sustainable alternative to fossil fuels. Because its combustion does not produce unwanted emissions. “When we burn hydrogen, there is no carbon dioxide (CO2) emission,” says chemistry professor Mathieu Frenette. It just makes water.”

Hydrogen could also be used to store large quantities of electricity from sustainable sources such as solar or wind power. When it is sunny or windy, large quantities of unused energy could be stored in the form of hydrogen, which would have the advantage of compensating for fluctuations in these energy sources.

Green hydrogen therefore presents itself as a flexible and ecological solution that can improve our energy supply. But there is a catch. “Production processes are expensive and are still not very efficient,” notes the professor. To make hydrogen a real asset in the decarbonization of the economy, significant improvements will have to be made.”

Generating hydrogen from water

This is the challenge that the group of the Projects in Materials Chemistry baccalaureate course offered by Mathieu Frenette and his colleagues Mohamed Siaj, director of the NanoQAM research center, and Joshua Byers, director of undergraduate programs in chemistry. “With the students, we undertook a project to develop a new conductive material to generate hydrogen from water,” says Mathieu Frenette. At the end of the experiments carried out in class, we even plan to publish a scientific article.

Green hydrogen (compared to gray hydrogen produced from natural gas) is obtained by electrolysis of water. “This process consists of passing an electric current through water (H2O) to break its molecules and extract the hydrogen,” explains the professor. One of the problems associated with this process is that platinum, widely used as a catalyst, costs more than gold. The other is that a significant amount of energy is lost in the process.

The students therefore sought to design a material without platinum or to reduce its use as much as possible. “A bit like the tree supports the leaves, we want to build an electrochemical support for the catalytic sites (the leaves of the tree), explains the chemist. And since the tree must supply water to all the leaves, our medium must conduct electricity to all the catalytic sites, which will eventually break down the water molecule.”

To design its electrochemical “trunk,” the class started with the idea of ​​taking sugar and treating it to make it conductive. By reacting sugar with sulfuric acid (an experiment often used to impress students during demonstrations in CEGEPs and high schools), we obtain a type of porous carbon that can be used as a support. “Other students have done tests with starch or cellulose,” adds the professor. There was even one who tested one of her hair.

Carbon obtained from sugar was finally chosen as a support. On this electrochemical “trunk”, the teams then added different metals (“sheets”) intended to serve as catalytic sites: nickel, iron, molybdenum, silver. “It’s a bit of a competition between the teams to determine which one will arrive at the lowest overpotential, that is to say at the smallest loss of energy,” explains the chemist.

Once the material has been developed, it must be characterized, that is, its properties must be described using a series of techniques aimed at determining its composition, structure and behavior. This is the activity carried out that day in the laboratories of the Department of Chemistry.

Access to high-tech equipment

Since the creation of NanoQAM in the Department of Chemistry, the research center dedicated to the synthesis and characterization of nanomaterials, an impressive fleet of equipment has been built up. Using these instruments, each worth a small fortune, is a privilege for the members of the research teams. “The new course allows us to give baccalaureate students much greater access to this high-tech equipment,” says the professor.

Technician Jacqueline Tieu is the backbone of the project. She is responsible for providing materials and reserving equipment. The class also counts on the help of three assistants: Lucille Kuster and Samaneh Esfahani, doctoral students, as well as their colleague Maziar Jafari, an atomic force microscope specialist who has just defended his thesis.

Between the tube furnace, the plasma torch, the laser microscope, the photo-induced force microscope, the X-ray diffractometer and other sophisticated equipment, seven or eight tests are necessary before even proceeding to the electrochemical assembly, the experimental technique which will allow the effectiveness of the material to be verified.

Thus, Maurielle Touko and Michael Belis are testing a mixture of nickel and molybdenum. In the third year of her baccalaureate, Maurielle Touko is aiming for a job in the pharmaceutical industry. His teammate, in his second year, works in the Environment Department of the City of Montreal. He is banking on his baccalaureate to improve his career prospects.

A real research project

In the meantime, they are a little nervous about the results of the tests on their material. “It’s stressful,” said the student, “because we don’t know what’s going to happen.” Both love the course, which allows them to get their hands dirty by working on a real research project.

Mathieu Frenette is almost as feverish. For him, hydrogen research is undoubtedly an area of ​​the future. With his colleagues, he has just obtained funding from the Quebec Center for Functional Materials to continue the project. “Even if our students end up working in another sector,” he emphasizes, “we contribute to training citizens who are aware of the fact that it makes sense to invest in this type of research.”

Source : Actualités UQAM