X-Fe (X = Mn, Co, Cu) Prussian Blue Analogue-Modified Carbon Cloth Electrodes for Capacitive Deionization

Abstract

Capacitive deionization is proven to be a viable resource-efficient alternative to remove dissolved salts from water. Further improvements in electrode materials are, however, necessary to achieve a higher efficiency of water desalination. In this work, X-Fe (X = Mn, Co, Cu) Prussian blue analogues of homogeneous particle sizes were grown on electrically conducting activated carbon cloth electrodes by a simple and facile synthesis process. As two-dimensional/three-dimensional (2D/3D) nanostructured Prussian blue analogue materials present favorable electrochemical behavior and ion-exchange possibilities, they are promising for application in capacitive deionization. The modified carbon cloth electrodes exhibit higher salt adsorption capacity and better charge efficiency compared to those constructed with pristine carbon cloth. Cobalt hexacyanoferrate-modified electrodes show the most stable performance, reaching a salt adsorption capacity of 14.47 mg g–1 at 1.0 V, accompanied by the lowest energy consumption (0.389 kWh m–3). This simple strategy is expected to offer possibilities for designing and synthesizing advanced electrode materials with superior performances for application in capacitive deionization devices.

Effect of Surface Charge on the Fabrication of Hierarchical Mn-Based Prussian Blue Analogue for Capacitive Desalination

“…Significantly, there is a strong peak at 2060 cm −1 corresponding to Fe−C�N−Mn, which confirms the high purities of the crystals. 39 For different substrates, there is basically no shift in peak positions. Meanwhile, another peak located at ∼591 cm −1 indicates the CN−Mn functional group.…”

“…Mn-based Prussian blue analogues (MPBs) were directly deposited on the substrates in this work by using a simple thermal deposition method . In a typical process, first, a piece of a substrate (ACC, FCC, CCC, NCC, GS, and NF, respectively, ∼4 × 4 cm 2 ) was immersed in 20 mL (10 mM) of K 3 Fe­(CN) 6 solution for about 3 h in a beaker.…”

“…Mn-based Prussian blue analogues (MPBs) were directly deposited on the substrates in this work by using a simple thermal deposition method. 39 In a typical process, first, a piece of a substrate (ACC, FCC, CCC, NCC, GS, and NF, respectively, ∼4 × 4 cm 2 ) was immersed in 20 mL (10 mM) of K 3 Fe(CN) 6 solution for about 3 h in a beaker. Then, 40 mL (10 mM) of manganese(II) acetate (Mn(CH 3 COO) 2 ) solution was added dropwise into the former, followed by stirring for 10 min at room temperature.…”

Sodium to cesium ions: a general ladder mechanism of ion diffusion in prussian blue analogs

“…Crystals of Cu-PBA were grown on a graphite foil (Minseal, thickness 0.18 mm) following the procedures described elsewhere. 10 In brief, a solution A was prepared consisting of 2 mM of potassium ferricyanide (K 3 Fe(CN) 6 ), and a solution B of 2 mM of copper( ii ) chloride (CuCl 2 ). A 5 × 5 cm piece of graphite foil was immersed for an hour in solution A before the deposition.…”

“…This makes them effective for energy storage 3 and desalination by capacitive deionization (CDI), among many potential applications. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] The versatile nature of PBAs further enables applications in carbon capture, 19 Fenton reactions, 20 sensing, 21 and biomedicine. 22,23 At the extreme end, it can even be applied for cesium decontamination [24][25][26][27][28] because the huge Cs + ions can passively replace K + ions in the matrix formed by the host structure.…”