Scientists explore ways to harness sustainable energy

By JESSICA KASAMOTO | September 20, 2018

With global warming such a hot button topic in today’s day and age, it is unsurprising that scientists have been continually searching for new renewable sources of energy that don’t harm our planet. While hydroelectric and solar energy are now common energy sources, scientists have seemingly combined the two practices in new studies at Ludwig Maximilian University of Munich (LMU) in Germany: Researchers at the university have split water molecules using solar energy. This could be a promising renewable energy source for future generations. 

While global warming has been discussed in the media for years, time and studies only seem to intensify how important green energy is and will be in the future. 

According to Josef Werne, a Geology and Environmental Science professor at the University of Pittsburg, signs of global warming are becoming more evident than ever before. 

“We can observe this happening in real time in many places. Ice is melting in both polar ice caps and mountain glaciers,” Joseff said, according to Live Science. “Lakes around the world, including Lake Superior, are warming rapidly — in some cases faster than the surrounding environment. Animals are changing migration patterns and plants are changing the dates of activity.”

Not only are the visual cues important in the detection of growing global warming, but also the quantitative as well. According to the National Oceanic and Atmospheric Administration (NOAA), the average global temperature has risen 1.78 degrees Fahrenheit over the last 100 years. In fact, 16 of the 17 hottest years on the planet have happened since the new millennium. The World Meteorological Organization reported in 2014 that the rising of the sea level has accelerated an average of about 0.12 inches per year, almost double the average of the 20th century. 

Therefore, it is hard to dispute that scientists should look for new ways to reduce fossil fuel emissions, which adversely affects global warming. While solar, wind, hydraulic, nuclear and biomass are the typical renewable “green” resources, Jacek Stolarczyk and Jochen Feldmann of LMU and Frank Würthner of the University of Würzburg have experimented with something much different than the norm. Together, the team has succeeded in the splitting of water molecules with an all-in-one catalytic system, something that has never been done before. In this process, a catalyst of semiconductor nanoparticles can help facilitate the photocatalytic splitting of water into hydrogen fuel and oxygen.

While this process can be quite complicated and challenging since many of the intermediate steps interfere with one another, these scientists have discovered that the best way to do this is to quite literally mimic the photosynthesis process in an everyday plant. 

The semiconductor nanoparticles absorb photons of light, which then act as photocatalysts. The absorption of this light particle generates an electron as well as another positively charged particle that scientists call a ‘hole.’ 

The electron and the hole must separate in order for the water to dissociate, the electron bonding to create hydrogen and the hole oxidizing the negatively charged oxygen.

“If one only wants to generate hydrogen gas from water, the holes are usually removed rapidly by adding sacrificial chemical reagent,” Stolarczyk said in a recent press release. “But to achieve complete water splitting, the holes must be retained in the system to drive the slow process of water oxidation.”

The biggest issue in the process is making the two reactions take place in the particle while preventing the positive hole and negative electron from recombining. 

They solved this problem by making nanorods of cadmium sulfate that will separate the oxidation reaction from the photocatalyst.

This project was a part of the German state of Bavaria’s interdisciplinary project entitled Solar Technologies Go Hybird (SolTech), which had the goal of further exploring the use of sunlight in renewable energy sources. 

”The development of the new photocatalytic system is a good example of how SolTech brings together the expertise available in diverse disciplines and at different locations,” said Würthner, who is also a founder of SolTech. 

“The project could not have succeeded without the interdisciplinary cooperation between chemists and physicists at two institutions.”

While this project can be appreciated from an environmentalist perspective, it can also be applauded as an example of the importance of academic cooperation between different fields. The LMU scientists are trained as physicists and Würthner is a chemist. 

In a brief interview with The News-Letter, Benjamin Straus, a sophomore at Hopkins majoring in Biomedical Engineering, described his take on the importance of academic collaboration in today’s world. 

“Interdisciplinary collaboration is critical to finding innovative solutions to some of today’s biggest problems. It allows for different perspectives to bring light to surprising solutions that are easily overlooked from a close viewpoint,” Straus said.

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