Structural characterization of electrodeposited copper hexacyanoferrate films by using a spectroscopic multi-technique approach

Abstract

A deep structural investigation predominantly by X-ray spectroscopic techniques is conducted on films of copper hexacyanoferrate (CuHCF) deposited under different conditions, aimed at establishing structure-properties relationships. We show that the potentiodynamic electrosynthesis of CuHCF on carbon-based surfaces produces a highly disordered material, with a variable amount of Prussian Blue (PB). The subsequent Cu(2+) intercalation induces the partial conversion of PB into CuHCF, which explains the improved electrocatalytic properties after the intercalation process. Both Cu and Fe K-edge data have been recorded. For the sample with the lower amount of PB, we could perform a multiple edge data analysis to determine the local atomic environment around both metal centres using the same set of structural parameters. The presence of high multiplicity Cu-N-C-Fe linear chains has allowed us to determine accurately the local environment of Fe while fitting the Cu K-edge data only. Using this approach we have retrieved structural information around Fe for those samples in which the concomitant presence of PB would have made impossible the analysis of the Fe K-edge. The Fe-C, C-N and Cu-N bond distances have been found in agreement with those of the bulk structures, but higher values of [Fe(CN)(6)] vacancies for the building blocks have been evidenced, reaching a value of ~45% in one sample. XANES, Raman and SEM data agree with the model proposed for each studied electrode.

Effect of Water and Alkali‐Ion Content on the Structure of Manganese(II) Hexacyanoferrate(II) by a Joint Operando X‐ray Absorption Spectroscopy and Chemometric Approach

“…However, as Fe−C≡N−Mn chains feature angles close to 180°, the actual number of parameters used to define the γ (3) or the γ (4) peaks was reduced by symmetry. Details on the use of parameter correlation in the four‐body term is out of the scope of this work and can be found elsewhere . Data analysis was performed by minimizing a χ 2 ‐like residual function that compares the theoretical (model) signal, μ mod (E), to the experimental one, μ exp (E).…”

“…However,a sF e ÀCNÀ Mn chains feature angles close to 1808,t he actual number of parameters used to define the g (3) or the g (4) peaks was reduced by symmetry.D etails on the use of parameter correlation in the fourbody term is out of the scope of this work and can be found elsewhere. [35] Data analysis was performed by minimizing a c 2 -like residual function that compares the theoretical (model) signal, m mod (E), to the experimental one, m exp (E). The phase shifts of the photoabsorber and backscatterer atoms were calculated from the structure reported by Song et al [8] according to the muffin-tin approximation and allowing 10 %o verlap between the muffin-tin spheres.…”

Electrochemical Preparation of Yttrium Hexacyanoferrate on Reduced Graphene Oxide and Its Application to Analgesic Drug Sensor

“…MHCFs have also been used for various applications, including dye sensitized solar cells 7, super capacitors 8, electrochromic devices 9, and biosensors 10 respectively. Relative to the transition metals based MHCFs 3–6, the rare earth metals based MHCFs with attractive morphologies and excellent electrocatalytic activities have been extensively used for various applications. With fascinating morphologies, some of the rare earth metal based MCFs, including LaHCF 11, CeHCF 12, YbHCF 13, and SmHCF 14 have been successfully demonstrated.…”

Electrodeposition of Prussian Blue/Carbon Nanotube Composites at a Liquid‑Liquid Interface

“…Therefore, the more ferric ions coordinate to N to form an organized cubic structure, the more CN modes shift. [72][73][74][75] Interaction between CNTs and as-synthesized PB occurs mainly through p-doping of CNTs, which transfer electron density to the metal species of the complex through a π-π interaction. 76,77 As a result of the increased density, the π back-bonding from cyano-ligands to the CNTs is enhanced, in turn improving the interaction between the materials.…”