Two new manuscripts from ACES' Professor Angel Cuesta have been published - the first deals with how the alkali metal ion in solution affects Pt deactivation during electro-oxidation, and the second with water at the electrode-electrolyte interface. These represent insights into fundamental electrochemistry which has potential impacts on understanding and utilising electrocatalysis for energy applications!
Two new publications from ACES' Professor Angel Cuesta and his group, including collaborations with researchers at Chemistry Institute, Universidade Estadual de Campinas (UNICAMP) in Brazil and State Key Laboratory of Physical Chemistry of Solid Surfaces in Xiamen, China, have been published. The first looks at how the alkali metal cation (such as Li+, Na+, and K+ present in solution when salts such as LiCl, NaCl and KCl or basic solution producing salts such as LiOH, NaOH and KOH are disolved in water) affects the ability for metallic Platinum to perform as a electro-catalyst. Usually, these ions are considered "spectator ions" and not involved directly in the chemistry. In this study, the researchers showed that the alkali metal cation affects the rate at which carbon monoxide is absorbed to the surface of the Platinum, which is the main mechanism by which the Platinum is "poisoned" or loses its activity. This explains observations in the literature where the cation affects the measurements, and could possibly be used to prevent such "poisoning" from taking place, allowing for easier electro-oxidation of small organic molecules.
The second paper, with the lead author Pavithra Gunasekaran also of ACES, studies the behavior of water at electrode-electrolyte interfaces by studying "HOD", a version of water wherein one of the hydrogens is replaced by the deuterium isotope. In this study they combine spectroscopic measurements with molecular dynamics simulations and note 1. a lack of an ice-like structure at the interface, as previously suggested and 2. at a critical applied voltage, the water molecules switch from having oxygen pointing towards the surface to away from the surface, but even after this switch, there are still water molecules that can accept hydrogen that require a significantly larger applied voltage to break up. This voltage is demonstrated to be larger than that at which most reactions on the metal surface take place, and thus cannot be part of the mechanism of these reactions.