A aerogel made of TiO2 and palladium. The credit is given to Markus Niederberger.
Aerogels have set Guinness World Records more than a dozen times, including as the world's lightest solid.
Professor Niederberger has been working with these special materials for a while. The lab specializes in aerogels. He says that the group is the only one in the world that can produce such high quality aerogel.
Aerogels based on nanoparticles can be used as photocatalysts. One example is the production of hydrogen, which can be done with the help of sunlight.
Titanium dioxide is a material used in photocatalysts. TiO2 can only absorb about 5 percent of the sun's light. If photocatalysis is to be efficient and useful, the catalyst needs to be able to use a broader range of wavelengths.
The spectrum can be expanded with nitrogen.
That's why Junggou Kwon is looking for a new way to make an aerogel. She had a brilliant idea that if the TiO2 nanoparticle aerogel is "doped" with nitrogen, it will absorb further visible portions of the spectrum. The porous structure of the aerogel is intact. The journal Applied Materials & Interfaces published a study on this method.
The photocatalytic production of hydrogen is a key role in the production of the aerogel, which was first produced using TiO2 and small amounts of noble metal palladium. She infused the aerogel with ammonia gas. The nitrogen atoms embedded themselves in the TiO2 nanoparticles.
The internal structure of the aerogel is sponge-like. The laboratory for multifunctional materials is located in ETH Zurich.
The reaction is more efficient because of the modified aerogel.
Kwon developed a special reactor to test whether an aerogel modified in this way actually increases the efficiency of a desired chemical reaction. She irradiated the reactor with two light-colored lights after introducing a vapor of water and methanol to it. The gaseous mixture diffuses through the aerogel's pores, where it is converted into hydrogen on the surface of the TiO2 and palladium nanoparticles.
The experiment was stopped after five days, but the reaction was stable and continued in the test system. The process would have been stable for a longer period of time. It's important for it to be stable for as long as possible. The researchers were happy with the results. Aerogels with palladium produced up to 70 times more hydrogen than those without.
The gas flow is increasing.
The experiment was used as a feasibility study. Aerogels are a new class of photocatalysts that offer an exceptional three-dimensional structure and have the potential for many other gas-phase reactions. Photocatalysts can be used to produce hydrogen using light instead of electricity, which is a big advantage compared to the current method of electrolysis.
It is not certain whether the aerogel developed by the group will ever be used on a large scale. There is still a question of how to accelerate the gas flow through the aerogel; at the moment, the extremely small pores hinder the gas flow too much. To operate such a system on an industrial scale, we first have to increase the gas flow and improve the irradiation of the aerogels. He and his group are working on these issues.
Aerogels are special. They are light and porous, and have a huge surface area, which can be up to 1,200 square meters. Aerogels have the appearance of frozen smoke due to their transparency. They are excellent thermal insulators and can be used in a variety of applications. The materials are expensive because they still need a lot of energy. The first aerogel was produced in 1931.
The Gas-Phase Nitrogen Doping of Monolithic TiO2 Aerogels for Efficient Visible Light-Driven Photocatalytic H2 Production was published in the journal Applied Materials & Interfaces. There is a book titled "acsami.1c12579."
The journal contains information about Applied Materials and Interfaces.
The new photocatalyst could enable more efficient hydrogen production.
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