Plant biomass is the key to producing environmentally friendly hydrogen fuel

What is it about?

Obtaining hydrogen fuel by photocatalysis is the key to developing renewable energy. Our research focused on creating an effective composite photocatalyst made up of two key components: graphitic carbon nitride g-C3N4 and titanium dioxide TiO2. We synthesized the photocatalyst using two methods for depositing TiO2 particles on g-C3N4: a simple deposition method and hydrothermal synthesis. The simple precipitation method allowed us to obtain a catalyst that was active in the hydrogen production from aqueous solutions of complex substances – glucose (a component of plant biomass) – under solar radiation.

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Photo by Caspar Rae on Unsplash

Photo by Caspar Rae on Unsplash

Why is it important?

In our work, we combined two light-responsive materials: g-C3N4, which absorbs visible light, and TiO2, which absorbs UV-light. When these two materials are brought into very close contact, they work even more effectively. At their interface, electric charges generated by light can move more easily and avoid recombining, which makes the whole process more efficient. We compared two different preparation methods and found that the way the materials are combined strongly affects their structure. Adding g-C3N4 during TiO2 synthesis changes the crystal size and the ratio between its two main forms, anatase and rutile. A simple deposition method produced the most favorable structure — with an optimal anatase-to-rutile ratio — and resulted in the highest activity. The resulting material efficiently produced hydrogen not only from glucose (a model compound related to biomass), but also from other organic substances. Interestingly, it performed better under simulated sunlight than under a LED source, because together the two components capture a broader portion of the solar spectrum.

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