Electrochromic Hysteresis Performance of a Prussian Blue Film Arising from Electron‐Transfer Control by a Tris(2,2′‐bipyridine)ruthenium(II)‐Doped WO₃ Film as Studied by a Spectrocyclic Voltammetry Technique

Abstract

A [Ru(bpy)(3)](2+) (bpy=2,2'-bipyridine)-doped WO(3) film was prepared as a base layer on a substrate by cathodic electrodeposition from a colloidal triad solution containing peroxotungstic acid (PTA), [Ru(bpy)(3)](2+), and poly(sodium 4-styrenesulfonate) (PSS). A Prussian blue (PB; Fe(II)-Fe(III)) film was cathodically electrodeposited on the [Ru(bpy)(3)](2+)-doped WO(3) film or neat WO(3) film from an aqueous Berlin brown (BB; Fe(III)-Fe(III)) colloid solution to yield a [Ru(bpy)(3)](2+)-doped WO(3)/PB bilayer film or WO(3)/PB bilayer film. For the spectrocyclic voltammogram (SCV) of the WO(3)/PB film, a redox response of Prussian white (PW; Fe(II)-Fe(II))/PB was observed at 0.11 V, however, further oxidation of PB to BB was not allowed by the interfacial n-type Schottky barrier between the WO(3) and PB layers. For the [Ru(bpy)(3)](2+)-doped WO(3)/PB film, any electrochemical response assigned to the redox of PB was not observed in the cyclic voltammogram, however, the in situ absorption spectral change recorded simultaneously showed the significant redox reactions based on PB. The SCV revealed that PW on the [Ru(bpy)(3)](2+)-doped WO(3) film is completely oxidized to PB by a geared reaction of Ru(II)/Ru(III) at 1.05 V, and that 32 % of PB formed is further oxidized to BB by the same geared reaction in the potential scan to 1.5 V. PB was completely re-reduced to PW by a geared reaction of H(x)WO(3)/WO(3) at -0.5 V in the reductive potential scan. These geared electrochemical reactions produced an electrochromic hysteresis performance of the PB film layered on the [Ru(bpy)(3)](2+)-doped WO(3) film.

Preparation and photoelectrocatalytic activity of a nano-structured WO3 platelet film

“…However, the photocatalytic and photoelectrochemical characteristics of WO 3 have not been studied as extensively as those of TiO 2 . WO 3 films have been prepared by several techniques, e.g., vacuum evaporation [9], chemical vapor deposition [10,11], sol-gel precipitation [12][13][14][15], spin coating [16], sputtering [17] and electrodeposition [18][19][20][21][22]. Although a sol-gel technique is one of the simple and low-cost procedures selected for a wide range of applications, there have been only a few reports on photoelectrochemical characteristics of the WO 3 film prepared by a sol-gel technique [12][13][14][15].…”

Nanoporous of W/WO3 Thin Film Electrode Grown by Electrochemical Anodization Applied in the Photoelectrocatalytic Oxidation of the Basic Red 51 used in Hair Dye

“…: vacuum evaporation, 19 chemical vapor, 20,21 sol-gel precipitation, [22][23][24][25] spin coating, 26 sputtering, 27 and electrodeposition. [28][29][30][31][32][33][34] Although a sol-gel technique is one of the simplest and lowest-cost procedures selected for a wide range of applications, there have been only a few reports on photoelectrochemical characteristics of the WO 3 film prepared by a sol-gel technique. [5][6][7][8] Several techniques for improving photoresponse of thin film electrodes W/WO 3 have already been proposed.…”

Prussian blue modified metal–organic framework MIL-101(Fe) with intrinsic peroxidase-like catalytic activity as a colorimetric biosensing platform

“…Prussian blue (PB) crystals consisting of iron ions coordinated by CN bridges are very typical coordination polymers with a high surface area, showing excellent properties in many applications such as catalysis, sensors, molecular magnets, gas storage. [30][31][32][33][34] Especially, PB exhibits high peroxidase-like catalytic activity for the reduction of hydrogen peroxide due to highly electroactivity. 35,36 However, owing to its limited dispersibility and functionalizability as well as its interfering strong blue color, PB has difficulty in applying for colorimetric biosensing in liquid solution.…”