Safa Jafari Safa, Office of Communications, firstname.lastname@example.org
Research conducted in the Department of Chemistry
at AUB that was recently published in ACS Catalysis, a prestigious high impact publication of the American Chemical Society (ACS), has been selected for ACS Editors’ Choice. An honor that is given to original research that “exemplifies the Society’s commitment to improving people's lives through the transforming power of chemistry,” it recognized the work led by Dr. Lara Halaoui for its “potential for broad public interest.”
The research aims to contribute to the understanding of oxygen evolution reaction catalysts from non-precious metals, and is seen to pave the way to sustainable solar water splitting systems for renewable energy solutions.
“We want to eventually store solar energy in high energy-density chemical bonds for use on demand by mimicking what nature did in photosynthesis,” said Halaoui. “The findings in this study are of fundamental value to understand a class of oxygen evolution catalysts made from cheap materials, and will have practical implications for the rational design of catalysts for efficient solar water splitting systems. Finding renewable energy sources that do not harm our environment is a priority now for sustaining our life on earth.”
In their two-year study of long hours of electrochemistry experiments, the AUB researchers worked to understand the promotion role of iron (Fe) atoms in enhancing oxygen evolution catalysis at Ni(Fe)-oxo/hydroxide catalysts, building on attempts to provide a renewable clean source of energy, hydrogen fuel, through efficient solar water splitting. In this study, the location of the active iron within the catalyst was examined by conducting a detailed electrochemical investigation of oxygen evolution reaction catalysis at Ni(Fe)-oxo/hydroxide catalysts, in the presence or absence of iron in the catalyst, and in solution during activation and during catalysis. The electrochemical data was found to be fully consistent with a new hypothesis that active iron is being generated at the surface post-deposition, rather than being included in the bulk during catalyst formation. This work also showed that the active site is in fact dynamic and not sustainable at the iron-activated Ni(Fe)-oxo/hydroxide catalysts in an iron-free solution.
Solar water splitting at a semiconductor electrode using visible light has long been considered a holy grail in chemistry. The oxygen evolution reaction is a four electron four proton process, and is kinetically very demanding, and has been traditionally catalyzed, to make it faster, by precious metal iridium and ruthenium oxides. In recent years, bimetallic nickel-iron-oxides/hydroxides have emerged as viable low cost candidates for oxygen evolution reaction, as they are formed of earth abundant metals, but the role that iron plays in promoting catalysis has remained elusive and many hypotheses have been proposed.
Dr. Lara I. Halaoui is a professor of chemistry at AUB who is an electrochemist by training. She leads a research program at AUB in electrochemistry and nanoscale materials focusing on renewable energy. Her investigations include the assembly of nanomaterials and light trapping effects in photonic materials for enhancing solar energy conversion in quantum dot solar cells and dye-sensitized solar cells, and in photoanodes for water oxidation. Halaoui also studies electrocatalysts from earth-abundant materials and their coupling to photoelectrodes for solar water splitting.
Working on this study within Halaoui’s team were two researchers, whom she refers to as “the examples of the best of AUB, the young minds that we teach and train,” MS student Rida Farhat, who started conducting research in Halaoui’s laboratory when he was a senior undergraduate student studying for his BS in chemistry at AUB, and research assistant Jihan Dhainy, who has been working in the laboratory for a number of years.
The preeminent comprehensive catalysis journal, ACS Catalysis, is dedicated to publishing top original research on molecular, enzymatic, and heterogeneous catalysis. Under ACS Editors’ Choice, ACS offers free public access to new research judged of importance to the scientific community. Articles are selected for the ACS Editors’ Choice based on the recommendations of scientific editors of ACS journals from around the world.
Source: https://pubs.acs.org/doi/10.1021/acscatal.9b02580 - further permissions related to the material excerpted should be directed to the American Chemical Society.