A UC Davis chemistry graduate student has been selected to conduct research at a U.S. Department of Energy (DOE) national laboratory through the DOE’s Office of Science Graduate Student Research (SCGSR) program.
Tatiana Mamani, a Ph.D. candidate in physical chemistry working with Professor of Chemistry Davide Donadio, is among 62 Ph.D. students selected nationwide to participate in this prestigious program. The SCGSR program gives graduate students the chance to learn from world-class scientists while using state-of-the-art equipment and facilities. Awardees work on research projects addressing critical energy, environmental and nuclear challenges.
Mamani will conduct research at the Lawrence Livermore National Laboratory (LLNL).
“It feels pretty unreal,” Mamani said. “I’m filled with gratitude toward Davide and Joel Varley who supported me in applying for the DOE SCGSR fellowship.”
Varley, a staff scientist in LLNL’s Quantum Simulations Group, will mentor Mamani during the six months of her fellowship.
“As a DOE SCGSR fellow, I will work with LLNL scientists and have access to LLNL resources. Their expertise and support will enable me to study materials at a scale which I currently am unable to,” Mamani said. “I’m excited to learn about the energy research happening there.”
Mamani’s research focuses on tuning materials to enhance solar-powered water splitting of hydrogen gas. The process harnesses sunlight to split water molecules into hydrogen and oxygen, with the end goal of creating a renewable source for hydrogen fuel.
“This proposal investigates how oxygen vacancies on the surface of perovskites — a type of semiconductor — impact the efficiency of hydrogen gas production from water,” Mamani said. “Specifically, this work focuses on the oxygen evolution reaction, the first half of the water splitting process, where oxygen is removed from water.”
During the oxygen evolution reaction phase, photons strike the surface of a semiconductor called a photoanode, leading to the generation of negatively charged electrons and positively charged particles called holes. When this happens, holes can then steal electrons from water, breaking the element into oxygen and protons, the latter being hydrogen gas precursors.
But particles can be fickle things. Sometimes, holes and electrons recombine. This reduces the amount of hydrogen gas produced by the solar-powered water splitting process.
“Oxygen vacancies play a role in this process by reducing electron-hole recombination, which boosts photovoltaic activity of the photoanode, but it’s unclear how surface oxygen vacancies specifically influence this process,” Mamani said. “This research aims to fill this gap by studying oxygen-deficient perovskites and analyzing how different oxygen vacancy configurations impact water interaction and catalysis.”
The research could inform the design of more efficient photoanodes.
“More efficient water splitting would be transformative for several renewable energy harvesting and storage technologies. While Tatiana's research is motivated by solar water splitting, her results may have an impact also on fuel cells and more efficient use of hydrogen as a fuel,” Donadio said. “This is a great chance for her to experience a different environment — the national lab — and learn new skills. It is also an enticing opportunity for me and my research group to establish new collaborations.”
Learn more about the Department of Energy’s Office of Science Graduate Student Research program.
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