Ternary Prussian Blue Analogs Research Articles

Cobalt/cerium-based ternary Prussian blue analogs as battery type electrode for supercapacitor applications

Supercapacitors are energy storage devices with remarkable properties including high power density, prolonged operational life, and hasty charging/discharging profile; however, a primary barrier to broad development is reduced energy density. Consequently, efforts have been undertaken to fabricate supercapacitors electrodes that resemble battery-type behavior. Owing to the unique structural characteristics and redox active sites, Prussian blue analogs (PBAs) are becoming attractive electrode materials. Herein, we presented the fabrication of ternary PBA-based electrode i.e., cerium cobalt hexacyanoferrate (CeCoHCF) with improved electrical properties and their characterization through different analytical techniques (SEM, FTIR, EDX, XPS, and XRD). The incorporation of cerium and cobalt together in PBA framework imparts a positive effect on the electrochemical properties. The as-synthesized CeCoHCF exhibits a significant specific capacity of 268.8 mA h g−1 at 1 A g−1 under alkaline conditions (3 M KOH) along with 88.6 % of capacity retention over 1000 cycles. Furthermore, the fabricated electrode exhibited the specific capacity 159.4 mA h g−1 at 1 A g−1 in neutral media (1 M Na2SO4). To investigate the practical application, symmetric supercapacitor device was fabricated that provides improved energy and power density as well as a wide operational voltage of around 1.2 V. Conclusively, PBA-based material can be potential candidates for future storage applications, owing to their outstanding electrochemical performance, chemical resilience, simplicity of synthesis, and low cost.

Reduced graphene oxide based aerogels: Doped with ternary Prussian blue analogs and selective removal of Cs+ from effluent

Reduced graphene oxide aerogels doped with ternary Prussian blue analogs (RGOA/TPBAs) were developed by controlled self-assembly tactics and applied to remove radioactive cesium (Cs) from effluent. The unique three-dimensional layered structure gives RGOA/TPBAs excellent mechanical strength and high-level specific surface area, which facilitates the exposure of adsorption points and thus promotes the adsorption of Cs+. A maximum adsorption capacity of 226.98 mg g−1 (dosage = 0.25 g L−1, pH = 7, T = 298.15 K) was obtained for the composite material, which exhibited excellent adsorption performance for cesium. In addition, RGOA/TPBAs maintained an excellent Cs+ selectivity in a solution containing other ions (m V−1 = 0.25 g L−1, Mn+ = Ca2+, Mg2+, Na+, K+, [Cs+]initial = 10 mg L−1) and the removal rate is more than 90%. The proposed secondary kinetic model (R2 = 0.9982) and fitted the adsorption process well, as does the Langmuir isotherm model (R2 = 0.9929), making it clear that the adsorption is homogeneous monolayer chemisorption. The coexisting ion adsorption experiments illustrate that the good selectivity of the composite.

Tunable critical temperature and magnetocaloric effect in ternary Prussian blue analogue

A comprehensive study of structural, magnetic and magnetocaloric properties in the ternary Prussian blue analogue (PBA) Ni1.5[Fe(CN)6]x[Cr(CN)6]1-x·nH2O (x = 0, 0.25, 0.5, 0.75 and 1) is presented. For all compounds the second-order magnetic phase transition from high temperature paramagnetic to the low temperature ferromagnetic state at the Curie temperature (Tc) is observed. We show the possibility of tuning the magnetic and magneto-caloric properties of PBA materials by changing the compositional factor of the metal centres involved in the cyano-bridging. An increase in Fe content leads to increase in the coercive field, whereas the critical temperature decreases from 60 to 22 K. The magnetic entropy change ΔS, as well as the related Relative Cooling Power (RCP), vary with x parameter in the regular way. The highest value of ΔS was observed for sample with x = 1 and was equal to 3.49 J mol−1K−1 under a magnetic field of 50 kOe, whereas the RCP varied from 62 J mol−1 (145.35 J kg−1) to 118 J mol−1 (273.33 J kg−1), when x decreased from 1 to 0.

ChemInform Abstract: Improving the Performance of a Ternary Prussian Blue Analogue as Cathode of Lithium Battery via Annealing Treatment.

AbstractNa1.1(VO)1.07Cu0.35 [Fe(CN)6]·5.9H2O and its annealed derivative Na1.1(VO)1.07Cu0.35 [Fe(CN)6]·H2O are prepared by precipitation from an ascorbic acid containing aqueous solution of V2O5 in H2O2 (30%) to which aqueous CuCl2 and Na4[Fe(CN)6] are given.

Improving the Performance of a Ternary Prussian Blue Analogue as Cathode of Lithium Battery via Annealing Treatment

AbstractA ternary prussian blue analogue (V1.07Cu0.35)Fe‐PBA and its annealed derivatives were prepared and investigated for their electrochemical behavior as lithium cathode material. The results indicate that the annealed one prepared at 200 °C under argon protection, though retains similar framework with the as‐prepared one, shows improved capacity (93 mA·h·g–1 at 50 mA·g–1), cycle stability (retaining 86 % of the capacity after 50 cycles) and rate capability, attributable to improved intercalation of Li ions via removing tunnel water from framework.

Magnetic properties of ternary Prussian Blue Analogs studied with genetic approach

There are some similarities between the formulation of numerous magnetic problems and the description of Genetic Algorithm (GA) representations and operators. In the paper we use GA to determine the ground-states of Prussian Blue Analog AB p C 1− p . The structure of this molecular magnet is formed by two interpenetrating sublattices: the first one consists of atoms A and vacancies, the second one consists of B and C atoms where p factor describes the stoichiometry. The interaction model includes nearest neighbor interactions and the single-ion anisotropy. Such a sample has already been the subject of study [1] with some approximated model. Using our approach we obtained in some regions of phase diagram configurations which are energetically better than known before. The thermodynamical analysis was performed using the specific algorithm of microcanonical Monte Carlo simulation, namely Creutz demon technique. It shows only small changes in the shape of the ferri-paramagnetic phase transition curve.

Compensation temperatures and magnetic susceptibility of a mixed ferro-ferrimagnetic ternary alloy

We study the compensation behaviour and magnetic susceptibility of a mixed ferro-ferrimagnetic ternary alloy of the type A B p C 1 − p on a cubic lattice by the use of Monte Carlo simulations. We consider that the A and X ( X = B or C) ions are alternately connected and have different Ising spins S A = 3 / 2 , S B = 2 , and S C = 5 / 2 , respectively. In particular, we find that the magnetic susceptibility may exhibit an outstanding behaviour in a vicinity of the critical and compensation temperatures. The relation of the studied model to ternary Prussian blue analogs is also discussed.