Unlocking the Potential of Amorphous Prussian Blue with Highly Active Mn Sites at Room Temperature for Impressive Oxygen Evolution Reaction and Super Capacitor Electrochemical Performance

Small. 2024 Feb;20(7):e2303946. doi: 10.1002/smll.202303946. Epub 2023 Oct 8.

Abstract

The key to increasing the rate of oxygen evolution reaction (OER) lies in accelerated four-electron dynamics, while the key to facilitating the development of supercapacitors lies in the design of electrode materials. This paper synthesized manganese-iron Prussian blue (MnFe-PBA@IF) at room temperature, and hexagonal concave structures w ere prepared using a fast-reducing matrix. Interestingly, MnFe-PBA@IF has an amorphous structure favorable to exposing more active surfaces. According to Gibbs free energy calculations on MnFe-PBA, charge depletion of manganese atoms can greatly enhance the adsorption of electron-rich oxygen-containing groups on the surface. Furthermore, the overpotential in 1 m KOH is 280 mV. Also, it can be used as a supercapacitor with a stable operating voltage range of -0.9-0 V and a specific capacity of 1260 F g-1 . This work provides new insights into the synthesis of OER catalysts for Prussian blue ferromanganese at room temperature. Non-gold-bonded adsorption, highly active metal centers and active surfaces are the underlying reasons for the superior performance of supercapacitors. Therefore, Prussian blue with good energy storage performance and high active surface can be used as multifunctional energy storage and conversion electrodes.

Keywords: Prussian blue analogs; iron manganese compounds; oxygen evolution reaction; room temperature mosaic structures; supercapacitors.