Binder-Free Fabrication of Prussian Blue Analogues Based Electrocatalyst for Enhanced Electrocatalytic Water Oxidation

Abstract

Developing a cost-effective, efficient, and stable oxygen evolution reaction (OER) catalyst is of great importance for sustainable energy conversion and storage. In this study, we report a facile one-step fabrication of cationic surfactant-assisted Prussian blue analogues (PBAs) Mx[Fe(CN)5CH3C6H4NH2]∙yC19H34NBr abbreviated as SF[Fe-Tol-M] (where SF = N-tridecyl-3-methylpyridinium bromide and M = Mn, Co and Ni) as efficient heterogeneous OER electrocatalysts. The electrocatalysts have been characterized by Fourier transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) analysis, and X-ray photoelectron spectroscopy (XPS). In the presence of cationic surfactant (SF), PBAs-based electrodes showed enhanced redox current, high surface area and robust stability compared to the recently reported PBAs. SF[Fe-Tol-Co] hybrid catalyst shows superior electrochemical OER activity with a much lower over-potential (610 mV) to attain the current density of 10 mA cm−2 with the Tafel slope value of 103 mV·dec−1 than that for SF[Fe-Tol-Ni] and SF[Fe-Tol-Mn]. Moreover, the electrochemical impedance spectroscopy (EIS) unveiled that SF[Fe-Tol-Co] exhibits smaller charge transfer resistance, which results in a faster kinetics towards OER. Furthermore, SF[Fe-Tol-Co] offered excellent stability for continues oxygen production over extended reaction time. This work provides a surface assisted facile electrode fabrication approach for developing binder-free OER electrocatalysts for efficient water oxidation.

Investigating electrochemical behavior of cobalt pentacyano(methylaniline)ferrate(ii) in various aqueous electrolytes for supercapacitor application

“…sodium pentacyanoammineferrate( ii ) [Fe–NH 3 ] and ligand substituted sodium pentacyano(methylaniline)ferrate( ii ) [Fe–Tol] were synthesized from sodium pentacyanonitrosylferrate( iii ) dihydrate (Na 2 [Fe III (CN) 5 NO]·2H 2 O) according to our previously reported procedure. 18 Other chemicals, i.e. cobalt nitrate hexahydrate Co(NO 3 ) 2 ·6H 2 O, sodium hydroxide, methanol, 2-methylaniline, polyvinylidene difluoride (PVDF), ethanol, acetone, diethyl ether, N -methyl-2-pyrolidine (NMP), lithium hydroxide, potassium hydroxide, and potassium nitrate purchased from Sigma-Aldrich (St. Louis, MO, USA).…”

“…Cobalt pentacyanoferrate (CoPCF) can be synthesized by the coprecipitation method with ordered morphology and a more active site as compared to the crystalline one. 18 Apart from the electrode materials, electrolytes significantly impact the electrochemical performance of the energy storage devices. The role of the electrolyte is crucial in determining the operating potential window (V) is directly linked with the resultant device's energy density.…”

“…Cobalt pentacyanoferrate (CoPCF) can be synthesized by the coprecipitation method with ordered morphology and a more active site as compared to the crystalline one. 18…”