Newswise – UNIVERSITY PARK, PA – Using solar power to inexpensively recover hydrogen from water could help replace carbon-based fuel sources and reduce the global carbon footprint. However, finding materials that could stimulate hydrogen production so that it can compete economically with carbon-based fuels has so far been an insurmountable challenge.
In a study, a team of researchers led by Penn State reports that it has taken a step forward to overcome the challenge of producing cheap hydrogen by using supercomputers to find materials that could help speed up the separation of hydrogen. hydrogen when water is exposed to light, a process called photocatalysis.
Electricity and solar energy can be used to separate hydrogen from water, which is made up of two hydrogen atoms and one oxygen atom, according to Ismaila Dabo, associate professor of science and technology. materials engineering. Affiliated with the Institute for Computational and Data Sciences (ICDS) and co-funded faculty member of the Institutes of Energy and the Environment. Using sunlight to generate electricity to create hydrogen – or electrolysis – which, in turn, would likely be converted back to electricity may not be technically advantageous or economically efficient. Although the direct use of solar energy to produce hydrogen from water – or photocatalysis – avoids this extra step, the researchers have not yet been able to use the direct solar conversion of hydrogen in a way that would compete with carbon-based fuels, such as gasoline.
The researchers, who report their findings in Energy and Environmental Science, used a type of computational approach called high-throughput material screening to narrow a list of more than 70,000 different compounds to six promising candidates for these photocatalysts, which when ‘they are added to water, can enable the process of producing solar hydrogen, Dabo said.
They reviewed the compounds listed in the Materials Project database, an open-access online repository of known and predicted materials. The team developed an algorithm to identify materials with properties that would make them suitable photocatalysts for the hydrogen production process. For example, researchers studied the ideal energy range – or bandgap – for materials to absorb sunlight. In close collaboration with Héctor Abruña, professor of chemistry at Cornell; Venkatraman Gopalan, professor of materials science and engineering at Penn State; and Raymond Schaak, professor of chemistry at Penn State; they also looked at materials capable of effectively dissociating water, as well as materials with good chemical stability.
“We believe that the integrated computational-experimental workflow that we have developed can dramatically accelerate the discovery of efficient photocatalysts,” said Yihuang Xiong, graduate research assistant and co-first author of the paper. “We hope that by doing so, we can reduce the cost of producing hydrogen.
Dabo added that the team focused on oxides – chemical compounds made up of at least one oxygen atom – because they can be synthesized in a reasonable amount of time using standard processes. The work required collaborations from all disciplines, which served as a learning experience for the research team.
“I found it very gratifying to have worked on such a collaborative project,” said Nicole Kirchner-Hall, doctoral student and co-author of the article. “As a graduate student specializing in computational materials science, I was able to predict possible photocatalysis. materials using calculations and working with experimental collaborators here at Penn State and other institutions to co-validate our computational predictions.
Other researchers have already conducted an economic analysis on several options for using solar energy to generate electricity and have determined that solar could lower the price of producing hydrogen to compete with gasoline, Dabo said.
“Their key conclusion was that if you could develop this technology, you could produce hydrogen at a cost of $ 1.60 to $ 3.20 per gallon equivalent of gasoline,” Dabo said. “So compare that to gasoline, which costs around $ 3 a gallon, if it works you could pay as little as $ 1.60 for about the same amount of energy as a gallon of gasoline in the scenario. ideal.”
He added that if a catalyst can help boost solar hydrogen production, it could lead to a competitive price of hydrogen compared to gasoline.
The team relied on Penn State’s ICDS Roar supercomputer for the calculations. Computers, according to Dabo, are an important tool in speeding up the process to find the right materials to use in specific processes. This data-intensive, calculation-based method could represent a revolution in efficiency compared to the labor-intensive trial and error approach.
“When Thomas Edison wanted to find materials for the bulb, he looked at just about any material under the sun until he found the right material for the bulb,” Dabo said. “Here we are trying to do the same thing, but in a way that uses computers to speed up this process.”
He added that computers will not replace experimentation.
“Computers can make recommendations as to which materials will be the most promising, and then you still have to do the experimental study,” Dabo said.
Dabo said he expects the power of computers to streamline the process of finding the best candidates and dramatically reduce the time it takes to design materials in the lab to bring them to market to meet needs.
The researchers evaluated machine learning algorithms to make suggestions of chemicals that could be synthesized and used as catalysts in the production of solar hydrogen. Based on this preliminary investigation, they suggest that future work may focus on developing machine learning models to improve the chemical screening process.
Dabo also added that they could look at chemical compounds besides oxides to determine if they could serve as catalysts for solar hydrogen production.
“So far we’ve cycled this process on oxides – basically rusty metals – but there are a lot of compounds that could be made that are not based on oxygen,” Dabo said. “For example, there are compounds based on nitrogen or sulfur we could explore.”
The National Science Foundation (NSF) and the US Department of Energy (DOE) HydroGEN Advanced Water Splitting Materials Consortium supported this work.
The team also included Quinn T. Campbell, postdoctoral researcher at Sandia National Laboratories; Julian Fanghanel, graduate student in materials science and engineering at Penn State; Catherine K. Badding, undergraduate chemistry student at Cornell and undergraduate science lab intern at DOE (now a graduate student at MIT); Huaiyu Wang, graduate student in materials science and engineering at Penn State; Monica J. Theibault, graduate student in chemistry at Cornell; Iurii Timrov, postdoctoral researcher at the Federal Polytechnic School of Lausanne, Switzerland; Jared S. Mondschein, graduate student in chemistry at Penn State; Kriti Seth, graduate chemistry student at Penn State; Rebecca Katz, graduate chemistry student at Penn State; Andrés Molina Villarino, graduate student in chemistry at Cornell; Betül Pamuk, postdoctoral researcher in physics at Cornell; Megan E. Penrod, undergraduate material science and engineering student at Penn State (now graduate student at University of Florida); Mohammed M. Khan, undergraduate material science and engineering student at Penn State (now graduate student at KAUST); Tiffany Rivera, NSF Research Experiences for Undergraduates Fellow; Nathan C. Smith, NSF Research Experiences for Undergraduates Fellow; Xavier Quintana, NSF Research Experiences for Undergraduates Fellow; Paul Orbe, NSF Research Experiences for Teachers Fellow; Craig J. Fennie, professor of physics at Cornell; Senorpe Asem-Hiablie, adjunct research professor of courtesy at the Penn State Institutes of Energy and the Environment; James L. Young, researcher at the National Renewable Energy Laboratory; Todd G. Deutsch, researcher at the National Renewable Energy Laboratory; and Matteo Coccioni, professor of physics at the University of Pavia, Italy.