Scientists obtain the molecular structure of interface water to provide a new way for green hydrogen production
Science and Technology Daily (Reporter Fu Xiaobo) Water molecules directly participate in many important electrocatalytic reactions, but the study of the structural changes and mechanism of action of water molecules at the solid-liquid two-phase interface during the electrocatalytic reaction has always been a difficult point in the electrochemical field. .
Recently, Professor Li Jianfeng’s team from the School of Chemistry and Chemical Engineering of Xiamen University and Professor Pan Feng’s team from Peking University Shenzhen Graduate School used electrochemical in-situ Raman spectroscopy to reveal the molecular structure of interfacial water molecules, and how the molecular structure of interfacial water regulates electrocatalysis The scientific research problem of reaction provides a new strategy for increasing the rate of electrocatalytic reaction and further guiding the green hydrogen production.
The results of this research were published in the journal Nature on December 2.
The research team used in-situ surface-enhanced Raman spectroscopy to monitor the configuration and dynamic changes of water molecules at the palladium single crystal electrode/solution interface during the electrocatalytic hydrogen evolution reaction.
The researchers found that in addition to the known water molecules containing hydrogen bonds at the electrode/solution interface, there is also a class of water molecules bound to cations on the interface.
In the latter, under the synergistic effect of the cation and the negative electrode potential, the disordered water molecules are arranged into a more orderly special structure.
This structure can accelerate the charge transfer between the electrode and the water molecules, thereby greatly increasing the rate of hydrogen evolution in the electrocatalytic reaction, providing a new theoretical approach for guiding green hydrogen production.
Studies have shown that this type of interface water molecules are closer to the electrode surface than hydrogen-bonded water molecules, which can increase the charge transfer efficiency between it and the electrode surface and greatly increase the rate of the electrocatalytic hydrogen evolution reaction.
Increasing the concentration and valence of cations will further increase the content of ordered water molecules in the interface zone and further increase the rate of the electrocatalytic hydrogen evolution reaction.
The study also found that the crystal surface structure and electronic structure of the single crystal electrode will affect the content of cation-bound water molecules and the rate of the electrocatalytic hydrogen evolution reaction, which confirms the universality of cation-bound water molecules to accelerate the rate of the electrocatalytic hydrogen evolution reaction.
Starting from the single crystal model system, this research deeply understands the regulation mechanism of the interfacial water molecular structure on the electrocatalytic reaction process, and solves the long-standing problems that have plagued the electrochemical field.