π-π interaction boosts catalytic oxygen evolution by self-supporting metal-organic frameworks

Abstract

The development of non-precious metal catalysts with excellent catalytic activities, stability and durability is important for efficient overall water splitting. Herein, free from any surfactant, three-dimensional flower-like FeNi metal organic framework (FeNi-MOF) composed of two-dimensional nanosheets have been formed by one-step wet-chemistry method. FeNi-MOF exhibit superior electrocatalytic OER performances with low overpotentials of 150 mV at 100 mA/cm2 and Tafel slopes of 38.7 mV/dec in alkaline media, and show remarkable catalytic stability for more than 100 h at large current densities. XPS, In-situ electrochemical Raman spectroscopy, UV–vis diffuse reflectance spectra, IR spectra and TG were used to explore the reasons for the excellent catalytic activity and long-lifes stability of the catalyst, and it was proved that the catalyst exhibits π-π interaction after the catalytic reaction, which leads to excellent catalytic activity and stability. Meanwhile, In situ electrochemical Raman spectroscopy was used to probe the specific transformation process during the OER. The density functional theory was used to further analyzed the intrinsically catalytic activity of FeNi-MOF.