Dr. Krishnan Rajeshwar, a chemist at the University of Texas at Arlington, has developed high-performing materials for cells that harness sunlight to split carbon dioxide and water into usable “green” fuels such as methanol and hydrogen gas.
The fuels would, in turn, be used to power cars, appliances and store energy in batteries.
“Technologies that simultaneously permit us to remove greenhouse gases like carbon dioxide while harnessing and storing the energy of sunlight as fuel are at the forefront of current research,” said the Indian American distinguished professor of chemistry and biochemistry.
Rajeshwar, also the co-founder of the university's center of renewable energy, science and technology, added, “Our new material could improve the safety, efficiency and cost-effectiveness of solar fuel generation which is not yet economically viable.”
The new hybrid platform uses ultra-long carbon nanotube networks with a homogeneous coating of copper oxide nanocrystals.
It demonstrates both the high electrical conductivity of carbon nanotubes and the photocathode qualities of copper oxide, efficiently converting light into the photocurrents needed for the photoelectrochemical reduction process, according to a university statement.
Rajeshwar's work is representative of the university's commitment to addressing critical issues with global environmental impact under the Strategic Plan 2020, the statement added.
“Dr. Rajeshwar's ongoing, global leadership in research focused on solar fuel generation forms part of UTA's increasing focus on renewable and sustainable energy,” said the university’s College of Science dean Morteza Khaledi. “Creating inexpensive ways to generate fuel from an unwanted gas like carbon dioxide would be an enormous step forward for us all.”
Rajeshwar worked with Csaba Janáky, an assistant chemistry professor at the University of Szeged in Hungary and Janáky’s master’s student Egon Kecsenovity, on the project. Janaky served as a UTA Marie Curie fellow from 2011 to 2013.
“The performance of our hybrid has proved far superior to the properties of the individual materials,” Rajeshwar said of the trio’s findings. “These new hybrid films demonstrate five-fold higher electrical conductivity compared to their copper oxide counterparts, and generate a three-fold increase in the photocurrents needed for the reduction process.”
The new material also demonstrates much greater stability during long-term photoelectrolysis than pure copper oxide which corrodes over time, forming metallic copper, the statement said.
Additionally, the team is designing, building and demonstrating a “microfluidic electrochemical reactor” to recover oxygen from carbon dioxide extracted from cabin air.
The prototype will be built over the next months at the center for renewable energy science and technology at UTA, said the findings published in the journal ChemElectroChem Europe and a companion article in the Journal of Materials Chemistry.
A graduate of the Indian Institute of Science in Bangalore, where he earned his doctorate degree, Rajeshwar joined the College of Science in 1983. He is charter member of the UTA Academy of Distinguished Scholars and senior vice president of The Electrochemical Society - an organization representing the nation's premier researchers who are dedicated to advancing solid state, electrochemical science and technology.
Rajeshwar, who completed his post-doctoral training at Colorado State University, is an expert in photoelectrochemistry, nanocomposites, electrochemistry and conducting polymers and has received numerous awards.