Electrochemical stability and capacitance of in-situ synthesized Prussian blue on thermally-activated graphite

Abstract

The search has been on for years to find at least, a stable, high surface area scaffold for Prussian blue (PB) and its analogs. If successful, PB's vast potential applications could be practicable. This, is besides other innate issues with PB such as poor cycle stability, low electronic conductivity to mention a few. For the first time, a stable Prussian blue@thermally activated graphite felt scaffold, with cycling stability of 2100 cycles, from − 0.5 to 1.3 V, and in 1 M KCl, for at least 36 h is reported. At the end of 2100 CV cycles, sample capacitance more than tripled (381 mF cm −2 compared to 120 mF cm −2 at start of experiment). These properties suggest a practical ion-sieve for specific cation removal from contaminated water. Two new synthesis protocols were employed to achieve this: (a) a first time, single solution PB synthesis without externally applied potential, current or even elevated temperature and (b) a two-step solution-dipping process not involving acidic conditions. PB from both protocols exhibited similar electrochemical characteristics even though the electron relay paths along their charge transfer complexes are different. When probed for its HOMO characteristics, the PB@thermally-treated graphite showed no significant electronic difference from the thermally-treated felt scaffold, suggesting non-compromise of the treated graphite by the PB. Besides cation removal, the electrochemical and electronic properties of these PB@treated graphites suggest multiple electrochemical, non-electrochemical and electronic applications with intact structural and functional integrity.

Stable Chitosan and Prussian Blue-Coated Laser-Induced Graphene Skin Sensor for the Electrochemical Detection of Hydrogen Peroxide in Sweat

“…The development of peaks at 217 and 276 cm –1 on the PB–CS-coated LIG, as shown in Figure B, is ascribed to FeCNFe vibrations and indicates the presence of Prussian blue. − However, the assignment of low-frequency bands (<300 cm –1 ) has rarely been reported in the literature. The peaks at 2099 and 2150 cm –1 on the PB–CS-coated electrodes are attributed to asymmetric and symmetric stretch vibrations of Fe II –CN–Fe III , respectively (Figure S3).…”

Synthesis, Catalytic Properties and Application in Biosensorics of Nanozymes and Electronanocatalysts: A Review

“…Insoluble PB can be described by the formula Fe 4 (Figure 6). PBAs are usually obtained via various techniques, including chemical [146,149,[159][160][161][162] and alternative biological methods [163].…”

“…The charge transfer through two transition metal ions in the complex-compound salt, as well as the nanosize of HCF particles, are the reasons for PBAs' redox activity and super-magnetic properties. Due to these remarkable properties, PBAs are widely applied as NZs in biosensors [146,147,150,[164][165][166][167][168] and alternative energy sources [149,160,165,168].…”

“…Despite their multifunctionality, the composition of PBAs is quite complicated and tightly depends on a method of synthesis and storage conditions. [ 146 , 149 , 150 , 151 , 159 , 160 ]. Insoluble PB can be described by the formula Fe 4 [Fe(CN) 6 ] 3 .…”

“…The general formula of hexacyanoferrate (HCF) is M k [Fe(CN) 6 ]·xH 2 O, where M is a transition metal ( Figure 6 ). PBAs are usually obtained via various techniques, including chemical [ 146 , 149 , 159 , 160 , 161 , 162 ] and alternative biological methods [ 163 ].…”