Dual In Situ Laser Techniques Underpin the Role of Cations in Impacting Electrocatalysts

Understanding the electrode/electrolyte interface is crucial for optimizing electrocatalytic performances. Here, we demonstrate that the nature of alkali metal cations can profoundly impact the oxygen evolution activity of surface-mounted metal-organic framework (SURMOF) derived electrocatalysts, which are based on NiFe(OOH). In situ Raman spectroscopy results show that Raman shifts of the Ni-O bending vibration are inversely proportional to the mass activities from Cs+ to Li+. Particularly, a laser-induced current transient technique was introduced to study the cation-dependent electric double layer properties and their effects on the activity. The catalytic trend appeared to be closely related to the potential of maximum entropy of the system, suggesting a strong cation impact on the interfacial water layer structure. Our results highlight how the electrolyte composition can be used to maximize the performance of SURMOF derivatives toward electrochemical water splitting.

Automated summary

Understanding the electrode/electrolyte interface is crucial for optimizing electrocatalytic performances. The nature of alkali metal cations has been found to have a profound impact on the oxygen evolution activity of SURMOF derived electrocatalysts based on NiFe(OOH). The effects of cation-dependent electric double layer properties on activity were studied using a laser-induced current transient technique. Electrolyte composition can be used to maximize the performance of SURMOF derivatives in electrochemical water splitting.