磁场效应对理解水分解反应物的可能意义

电催化水分解由两个基元反应构成,即析氢反应(HER)和析氧反应(OER).开发强大的HER和OER技术需要在分子层面理解反应机理,然而,目前水分解反应的反应物还没有完全确定.本文利用磁场来研究HER中的质子传输和OER中的氢离子传输,对确定HER和OER中真实的反应物具有重要意义.磁场是改变离子等带电物质运动的一种有效...

The possible implications of magnetic field effect on understanding the reactant of water splitting

Electrochemical water splitting consists of two elementary reactions i.e., hydrogen evolution reac-tion (HER) and oxygen evolution reaction (OER). Developing robust HER and OER technologies necessitates a molecular picture of reaction mechanism, yet the reactants for water splitting reac-tions are unfortunately not fully understood. Here we utilize magnetic field to understand proton transport in HER, and hydroxide ion transport in OER, to discuss the possible implications on un-derstanding the reactants for HER and OER. Magnetic field is a known tool for changing the move-ment of charged species like ions, e.g. the magnetic-field-improved Cu2+ transportation near the electrode in Cu electrodeposition. However, applying a magnetic field does not affect the HER or OER rate across various pH, which challenges the traditional opinion that charged species (i.e. pro-ton and hydroxide ion) act as the reactant. This anomalous response of HER and OER to magnetic field, and the fact that the transport of proton and hydroxide ion follow Grotthuss mechanism, col-lectively indicate water may act as the universal reactant for HER and OER across various pH. With the aid of magnetic field, this work serves as an understanding of water might be the reactant in HER and OER, and possibly in other electrocatalysis reactions involving protonation and deproto-nation step. A model that simply focuses on the charged species but overlooking the complexity of the whole electrolyte phase where water is the dominant species, may not reasonably reflect the electrochemistry of HER and OER in aqueous electrolyte.