Prussian Blue Graphene Oxide Research Articles

Rational design of novel ultra-small amorphous Fe2O3 nanodots/graphene heterostructures for all-solid-state asymmetric supercapacitors

Constructing graphene-based heterostructures with large interfacial area is an efficient approach to enhance the electrochemical performance of supercapacitors but remains great challenges in their synthesis. Herein, a novel ultra-small amorphous Fe2O3 nanodots/graphene heterostructure (a-Fe2O3 NDs/RGO) aerogel was facilely synthesized via excessive metal-ion-induced self-assembly and subsequent calcination route using Prussian blue/graphene oxide (PB/GO) composite aerogel as precursors. The deliberately designed a-Fe2O3 NDs/RGO heterostructure offers a highly interconnected porous conductive network, large heterostructure interfacial area, and plenty of accessible active sites, greatly facilitating the electron transfer, electrolyte diffusion, and pseudocapacitive reactions. The obtained a-Fe2O3 NDs/RGO aerogel could be used as flexible free-standing electrodes after mechanical compression, which exhibited a significantly enhanced specific capacitance of 347.4 F·g−1 at 1 A·g−1, extraordinary rate capability of 184 F·g−1 at 10 A·g−1, and decent cycling stability. With the as-prepared a-Fe2O3 NDs/RGO as negative electrodes and the Co3O4 NDs/RGO as positive electrodes, an all-solid-state asymmetric supercapacitor (a-Fe2O3 NDs/RGO//Co3O4 NDs/RGO asymmetric supercapacitor (ASC)) was assembled, which delivered a high specific capacitance of 69.1 F·g−1 at 1 A·g−1 and an impressive energy density of 21.6 W·h·kg−1 at 750 W·kg−1, as well as good cycling stability with a capacity retention of 94.3% after 5,000 cycles. This work provides a promising avenue to design high-performance graphene-based composite electrodes and profound inspiration for developing advanced flexible energy-storage devices.

Enhanced adsorption of cesium on PVA-alginate encapsulated Prussian blue-graphene oxide hydrogel beads in a fixed-bed column system

A continuous fixed-bed column study was performed using PVA-alginate encapsulated Prussian blue-graphene oxide (PB-GO) hydrogel beads as a novel adsorbent for the removal of cesium from aqueous solutions. The effects of different operating parameters, such as initial cesium concentration, pH, bed height, flow rate, and bead size, were investigated. The maximum adsorption capacity of the PB-GO hydrogel beads was 164.5mg/g at an initial cesium concentration of 5mM, bed height of 20cm, and flow rate of 0.83mL/min at pH 7. The Thomas, Adams–Bohart, and Yoon–Nelson models were applied to the experimental data to predict the breakthrough curves using non-linear regression. Although both the Thomas and Yoon–Nelson models showed good agreement with the experimental data, the Yoon–Nelson model was found to provide the best representation for cesium adsorption on the adsorbent, based on the χ2 analysis.

One-pot synthesis of ternary polypyrrole⿿Prussian-blue⿿graphene-oxide hybrid composite as electrode material for high-performance supercapacitors

A ternary composite of polypyrrole (PPy), Prussian blue (PB), and graphene oxide (GO), PPy⿿PB⿿GO, was successfully prepared through spontaneous polymerization of pyrrole and formation of PB nanocubes on GO. The obtained nanocomposite was characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. The results indicate that the PPy-protected PB nanocubes were well dispersed on the GO. Electrochemical testing showed a specific capacitance of 525.4Fg⿿1 at a current density of 5Ag⿿1 in the potential range from ⿿0.2 to 0.6V, obtained in an electrolyte of 1molL⿿1 KNO3 during the galvanostatic charge⿿discharge cycles, which is superior to the performance of binary cathode materials, including PPy⿿PB and PPy⿿GO nanocomposites. The as-prepared supercapacitor could retain a specific capacitance of 96% after 2000 cycles. It was confirmed that the three components⿿PPy, PB, and GO⿿led to the display of integrated electrochemical behavior and a resulting capacitor with enhanced performance. The significant enhancement in electrochemical performance of the ternary nanocomposite can be attributed to the synergistic effect of PPy-protected PB nanocubes dispersed on GO sheets with the pseudocapacitance from PB and PPy on the double-layer capacitance from GO.