For decades, researchers studying the conversion of light energy into electrical or chemical energy — such as in solar cells — have focused on the movement of electrons, which are central to the process.
But in a new study in the journal Chem, Yale chemists James Mayer and Hyunho Noh take a different approach. They looked at energy conversion reactions as a type of “whole atom” transfer of hydrogen atoms, which have one electron and one proton, and are found in most energy conversion reactions.
For the study, Mayer, the Charlotte Fitch Roberts Professor of Chemistry in Yale’s Faculty of Arts and Sciences, and Noh, a postdoctoral associate in chemistry, measured the thermodynamics of hydrogen-atom binding to nickel oxide electrodes when in contact with three solvents: water, dimethylformamide, and acetonitrile.
“Our work shows that the ‘electron-only’ model is not sufficient,” Mayer said. “The other new approach this paper develops is that the solid/solution interface has a range of surface sites, with somewhat different strengths of chemical bonds. While this range of energies is well known in some areas of surface science, the importance of this effort has not been emphasized.”
They found that the binding of hydrogen was the same no matter which solvent they used or what was dissolved in the solution, showing that this parameter is the best intrinsic property of the electrode, while the electron-only parameters vary strongly with the nature of the medium.