GILL — When Northfield Mount Hermon School senior Angus Chang engineered an artificial leaf, a sustainable battery of microalgae and metal suspended in hydrogel, he felt his creation was too simple to consider impressive.

After all, Chang’s inspiration originated from a childhood experiment with fruit batteries and his family’s air-purifying house plants. The development process was conducted in Chang’s home using equipment he borrowed from school, and each artificial leaf costs only $3 to make.

Yet despite his doubts, Chang has been receiving national and international recognition for his artificial leaf for the past two years. Most recently, Chang was one of 300 high school seniors to be named a 2023 Regeneron Science Talent Search scholar, having competed with nearly 2,000 students from across the United States, Puerto Rico and four other countries.

According to Regeneron Science Talent Search Director Allie Stifel, the competition, held through the nonprofit Society of Science, searches for the future leaders of STEM. To qualify for the contest, applicants must complete individual research in science, technology, engineering or mathematics during their high school career. Experiments range from lab work with complex equipment to analyses of societal issues and large data sets.

Chang calls his invention the artificial leaf because of the single-cell microalgae called chlorella. Chlorella has high conductivity, allowing it to carry electric currents while simultaneously photosynthesizing oxygen.

“I always have thought that I’m going to make an invention that actually can be eco-friendly to provide to our community,” said Chang, who is from Taiwan. “I figured out how to use the microalgae and also for there [to be a] battery reaction. … It’s just like an artificial leaf. It can absorb the sunlight [and] due to photosynthesis it can generate oxygen, just like a leaf.”

The crux of Chang’s research investigates the types of metals that produce the battery’s highest voltage and the substance that can hold and support the microalgae. The invention requires a material with high water retention and air permeability, considering water and carbon dioxide need to enter the leaf for the chlorella to survive, but oxygen must also be able to leave the leaf to purify the air. Chang found his answer in hydrogels, a popular carbohydrate that marathon runners use to refuel during runs.

The artificial leaf uses magnesium and copper metals to create electricity, the combination Chang discovered generates the most electricity. The current model produces power equivalent to that of an AA battery.

“I know this competition is really competitive. I want to let people know about this idea; that is what is important to me, not the outcome,” Chang said, adding that he hopes people will share his idea to benefit the community.

The Regeneron Science Talent Search application includes sections on community leadership roles, integrity of students and activities unrelated to science, technology, engineering and math. Stifel said these sections allow for a holistic review of each student.

“We know future leaders in STEM can come from all places and all different backgrounds,” Stifel said. “Maybe they didn’t have someone to look over their project and did it all on their own, so [the lab report] may be a little less polished.”

Stifel said this year’s Regeneron Science Talent Search saw applications return to pre-pandemic numbers and included more competitive applicants. She also noticed more students, like Chang, conducting experiments at home and communicating with mentors over video chat or email due to lab closures during the pandemic.

Chang borrowed equipment from science teacher Jolene Schuster at NMH to test his invention at home. Both Schuster and Dr. Meng-Chou Lee, an aquaculture professor at National Taiwan Ocean University, mentored Chang on the project. Each Regeneron Science Talent Search scholar receives a $2,000 award, with an additional $2,000 going to their respective school.

The artificial leaf also won awards through the 2022 Regeneron International Science and Engineering Fair, American Chemical Society, the 2022 Junior Science and Humanities Symposium, and the 2021 S.-T. Yau High School Science Awards.

Partnering with NMH students Joshua Wang and Wilson Cheung, Chang is now working to industrialize the artificial leaf through an international entrepreneur contest called the Diamond Competition. He hopes to continue to improve on the invention once he starts college.

“[The Regeneron Science Talent Search] boosted my confidence because I had a little dream about being a scientist, to do research in college,” Chang said. “And I think [becoming a scholar] actually helps me in this process.”

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