Atomically Local Electric Field Induced Interface Water Reorientation for Alkaline Hydrogen Evolution Reaction

The hydrogen evolution reaction (HER) in alkaline conditions is limited by the slow dissociation of water molecules. Water orientation at the catalyst surface is known to influence this process, but controlling orientation remains a challenge due to random molecular distribution. Prior research has shown that interfacial water orientation affects dissociation rates. However, no prior work had resolved how to manipulate this orientation systematically. Existing catalysts lack the precision to control water molecule alignment. This gap motivated researchers to explore new methods for inducing controlled water orientation. The need for a reliable mechanism to enhance HER kinetics in alkaline environments remains unmet. Understanding the role of local electric fields in catalytic processes is an emerging area. The field requires innovative approaches to manipulate interfacial water behavior.

This study aimed to develop a method for inducing controlled water orientation at the catalyst interface to enhance the hydrogen evolution reaction (HER) in alkaline conditions. The specific problem is the slow water dissociation rate caused by random water molecule distribution. The motivation comes from the need to improve HER efficiency in alkaline electrolytes. The researchers sought to design a system that could manipulate water orientation through an engineered electric field. The goal was to test whether atomically asymmetric electric fields could influence water dissociation. The study focused on using single-atom catalysts to generate localized electric fields. The approach involved combining experimental and computational methods to verify the mechanism. The ultimate aim was to provide a new strategy for enhancing HER performance.

The researchers designed IrRu dizygotic single-atom catalysts (IrRu DSACs) to generate an atomically asymmetric local electric field. The catalyst structure was engineered to create a strong electric field gradient at the interface. Ab initio molecular dynamics simulations were used to model water adsorption and dissociation processes. In situ Raman spectroscopy was employed to analyze the adsorption behavior of water molecules. The study combined experimental and computational approaches to validate the mechanism. The electric field intensity was measured and found to exceed 4.00×10¹⁰ N/C. The orientation of water molecules was observed to change in response to the electric field. The researchers tested how this orientation change affected the dissociation process of interfacial water.

The IrRu dizygotic single-atom catalysts generated an electric field intensity over 4.00×10¹⁰ N/C. This field altered the adsorption configuration of water molecules at the interface. The M-H bond length (M=active site) was shortened due to the electric field gradient. In situ Raman spectroscopy confirmed changes in water orientation at the interface. The optimized orientation promoted faster dissociation of interfacial water molecules. Ab initio simulations supported the experimental findings on water reorientation. The shortened M-H bond length suggests enhanced proton transfer efficiency. The results indicate that the local electric field significantly improves the dissociation process.

The study demonstrates that an atomically asymmetric electric field can influence water orientation at the catalyst interface. The IrRu dizygotic single-atom catalysts effectively generated a strong local electric field. This field altered water adsorption and dissociation processes in alkaline conditions. The shortened M-H bond length supports the role of the electric field in promoting dissociation. The findings suggest that engineered electric fields can enhance HER performance. The researchers propose that this approach offers a new strategy for improving alkaline HER. The study confirms the potential of single-atom catalysts in manipulating interfacial water behavior. The authors suggest that this method could be applied to other catalytic processes involving water dissociation.