Photocatalysis: How Effective Is This New Approach to Optimize an Aerogel Made of TiO2 Nanoparticles?

Laboratory for Multifunctional Materials Professor Markus Niederberger, at ETH Zurich, has been working on unusual materials, specifically, aerogels-based nanoparticles known as photocatalysts.

As specified in a Phys.org report, aerogels are distinctive materials "that have set Guinness World Records" more than a dozen times which include being the lightest solids of the world.

According to Professor Niederberger, he has been working on these said materials for some time already. His laboratory specializes in aerogels comprising crystalline semiconductor nanoparticles.

He explained that they are the only group in the world to produce this aerogel type at such high quality.

One use of the unique material based on nanoparticles is photocatalysts. They are employed each time there is a need for a chemical reaction to be enabled or fast-tracked with the help of sunlight, an instance being hydrogen production.

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(Photo: RainbowDasha on Wikimedia Commons)
Photocatalysis in oxygen

Titanium Dioxide

Essentially, the choice material for photocatalysts is a semiconductor known as titanium dioxide or TiO2. However, TiO2 has a major drawback. Specifically, it can absorb just the UV part of sunlight, only roughly five percent of the spectrum.

More so, if photocatalysis is found effective, not to mention industrially useful, there is a need for the catalyst to employ a broader range of wavelengths.

This is why Junggou Kwon, a doctoral student of Niederberger, has been looking for a new approach to optimize an aerogel made of TiO2 nanoparticles.

That is why Niederberger's doctoral student Junggou Kwon has been looking for a new way to optimize an aerogel made of TiO2 nanoparticles, Nanowerk said in a similar report.

Modified Aerogel

To find out if an aerogel modified in this manner indeed enhanced the effectiveness of the desired chemical reaction, in this case, the hydrogen production from wat and methanol, Kwon devised a special reactor into which she placed the aerogel monolith directly.

Then, she introduced a vapor of water and methanol to the aerogel in the reactor prior to irradiating it with a pair of LED lights.

The gaseous mixture is diffusing through the pores of aerogel, where it is converted into the desired hydrogen on the TiO2's surface, as well as palladium nanoparticles.

Five days after, Kwon stopped the experiment, although up to that point, the reaction was found stable and carried on continuously in the test system.

Employed to Generate Hydrogen

This study, published in ACS Applied Materials & Interfaces, served the researchers mainly as a feasible study. As a new photocatalyst class, aerogels provide an exceptional three-dimensional construction, not to mention the potential of many other interesting gas-stage reactions on top of hydrogen production.

Compared to the electrolysis that's typically used at present, photocatalysts have the benefit that they could be employed to generate hydrogen using just light instead of electricity.

Whether the aerogel that the group of Niederberger will ever be used on a large scale remains uncertain; for instance, there remains a question of how to fast-track the flow of gas through the aerogel. At present, the very tiny pores are hindering the flow of gas too much.

To operate the system, the expert explained, on an industrial scale, first, there is a need to increase the flow of gas and enhance the aerogels' irradiation. His team is already working on the said issues.

Related information about photocatalysis is shown on Certified Germ Control's YouTube video below:

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