Synthesis of Hollow Co–Fe Prussian Blue Analogue Cubes by using Silica Spheres as a Sacrificial Template

Abstract

Herein, we report a novel method for the formation of hollow Prussian blue analogue (CoFe–PBA) nanocubes, using spherical silica particles as sacrificial templates. In the first step, silica cores are coated by a CoFe–PBA shell and then removed by etching with hydrofluoric acid (HF). The cubic shape of CoFe–PBA is well‐retained even after the removal of the silica cores, resulting in the formation of hollow CoFe–PBA cubes. The specific capacity of the hollow CoFe–PBA nanocubes electrodes is about two times higher than that of solid CoFe–PBA nanocubes as storage materials for sodium ions. Such an improvement in the electrochemical properties can be attributed to their hollow internal nanostructure. The hollow architecture can offer a larger interfacial area between the electrolyte and the electrode, leading to an improvement in the electrochemical activity. This strategy can be applied to develop PBAs with hollow interiors for a wide range of applications.

Tuning Metal Elements in Open Frameworks for Efficient Oxygen Evolution and Oxygen Reduction Reaction Catalysts

“…Although the relative ratios between Co 2+ and Ni 2+ vary among different catalysts, the coordination environment of Co 2+ and Ni 2+ is not affected. Though M-PBA catalysts were synthesized through different metal ion-exchange reactions, they demonstrated a face-centered cubic structure with the Fm 3 m unit cell . The M-PBA showed strong intensity peaks at 17.4, 24.9, and 35.5°, which correspond to the (200), (220), and (400) faces, respectively. , In Figure S7, PB shows a main vibration peak at ∼2154 cm –1 , corresponding to the stretching of Fe 2+ –NC–Fe 3+ .…”

3D Spatial Combination of CN Vacancy‐Mediated NiFe‐PBA with N‐Doped Carbon Nanofibers Network Toward Free‐Standing Bifunctional Electrode for Zn–Air Batteries

“…Many researchers have studied the microstructure and/or catalytic mechanism of PBAs to further improve the catalytic activity. [ 13–17 ] For example, Galan‐Mascaros et al. [ 18 ] verified that Co‐Fe PBA catalyst exhibits more efficient and stable catalytic performance for OER after chemical etching treatment.…”

“…Many researchers have studied the microstructure and/or catalytic mechanism of PBAs to further improve the catalytic activity. [13][14][15][16][17] For example, Galan-Mascaros et al [18] verified that Co-Fe PBA catalyst exhibits more efficient and stable catalytic performance for OER after chemical etching treatment. Thereinto, manipulating the defect chemistry is a popular and efficient strategy to tune the catalytic activity of materials.…”

Formation mechanisms of hollow manganese hexacyanoferrate particles and construction of a multiple-shell structure

“…without changing the crystal lattice, resulting in high durability for the repetition. 22 Due to the redox property, PBAs have been studied for numerous electrochemical applications, including secondarybatteries, [3][4][5][6][7][22][23][24] electrochromic displays, [25][26][27][28] and electrochemical sensors. 8 Similar to other PBAs, Mn-HCF is also expected to be applied in Li + or Na + -ion secondary batteries.…”

“…One way is using substances other than PBA, such as Au 42 or SiO 2 . 5 Even PBA is available as the core if the solubility is relatively higher than that for the shell, depending on the compositional differences, as in the Mn 3 [Fe(CN) 6 ] 2 core for the RbCo[Fe(CN) 6 ] shell. 43 Mn 2+ ions in Mn 3 [Fe(CN) 6 ] 2 can be ion-exchanged with Co 2+ ions to form Co-HCF hollow particles also based on the solubility difference.…”