Rational Design and Synthesis of Cyano-Bridged Coordination Polymers with Precise­ Control of Particle Size from 20 to 500 nm

Prussian Blue Nanozymes with Enhanced Catalytic Activity: Size Tuning and Application in ELISA-like Immunoassay

Prussian blue nanozymes possessing peroxidase-like activity gather significant attention as alternatives to natural enzymes in therapy, biosensing, and environmental remediation. Recently, Prussian blue nanoparticles with enhanced catalytic activity prepared by reduction of FeCl₃/K₃[Fe(CN)₆] mixture have been reported. These nanoparticles were denoted as ‘artificial peroxidase’ nanozymes. Our study provides insights into the process of their synthesis. We studied how the size of nanozymes and synthesis yield can be controlled via adjustment of the synthesis conditions. Based on these results, we developed a reproducible and scalable method for the preparation of ‘artificial peroxidase’ with tunable sizes and enhanced catalytic activity. Nanozymes modified with gelatin shell and functionalized with affine molecules were applied as labels in colorimetric immunoassays of prostate-specific antigen and tetanus antibodies, enabling detection of these analytes in the range of clinically relevant concentrations. Protein coating provides excellent colloidal stability of nanozymes in physiological conditions and stability upon long-term storage.

Strategies for synthesis of Prussian blue analogues

We report a comparison of different common synthetic strategies for preparation of Prussian blue analogues (PBA). PBA are promising as cathode material for a number of different battery types, including K-ion and Na-ion batteries with both aqueous and non-aqueous electrolytes. PBA exhibit a significant degree of structural variation. The structure of the PBA determines the electrochemical performance, and it is, therefore, important to understand how synthesis parameters affect the structure of the obtained product. PBA are often synthesized by co-precipitation of a metal salt and a hexacyanoferrate complex, and parameters such as concentration and oxidation state of the precursors, flow rate, temperature and additional salts can all potentially affect the structure of the product. Here, we report 12 different syntheses and compare the structure of the obtained PBA materials.

Synthesis of nickel hexacyanoferrate nanocubes with tuneable dimensions via temperature-controlled Ni2+-citrate complexation

The citrate-assisted growth of nickel hexacyanoferrate (NiHCF) nanocubes was investigated. Control over the complexation of Ni2+ ions with citrate at different temperatures enabled fine tuning of the nanocrystal (NC) dimensions and their self-assembly into mesocrystals. Our results introduce new concepts towards the synthesis of NiHCF NCs, potentially applicable to other members of the Prussian blue analogues family.

Superparamagnetic nanoarchitectures for disease-specific biomarker detection

Synthesis, bio-functionalization, and multifunctional activities of superparamagnetic-nanostructures have been extensively reviewed with a particular emphasis on their uses in a range of disease-specific biomarker detection and associated challenges.

Effect of surface acidity of cyano-bridged polynuclear metal complexes on the catalytic activity for the hydrolysis of organophosphates

Heterogeneous catalysis of cyano-bridged polynuclear metal complexes was examined for the hydrolysis of toxic organophosphates. The surface acidity of cyano-bridged polynuclear metal complexes strongly effects on the catalytic activity.

Ball-in-cage nanocomposites of metal-organic frameworks and three-dimensional carbon networks: synthesis and capacitive performance

In order to improve the electrical conductivity of metal-organic frameworks (MOFs) which have drawn remarkable attention owing to their potential application in the energy storage field, a Co-based zeolitic imidazolate framework (ZIF-67) polyhedron was in situ integrated into a three-dimensional carbon network (3DCN) to construct a Ball-in-Cage (BIC) nanostructure. The introduced 3DCN acting as the electronic pathway can provide nucleation sites for MOF particles; consequently, further growth of the MOF particles is limited by the size effect of 3DCN. The BIC frame not only controls the MOF particle size, but also ensures a high electron conductivity of the entire structure. The as-prepared BIC electrode displays an outstanding capacitance of 119 F g^-1 at a current density of 0.5 A g^-1 and a great rate performance as well, which can be expected to be a promising approach to enhance the electrochemical performance of pristine MOFs in the future.

Rocking Chair Desalination Battery Based on Prussian Blue Electrodes

The demand for fresh water has been increasing, caused by the growing population and industrialization throughout the world. In this study, we report a capacitive-based desalination system using Prussian blue materials in a rocking chair desalination battery, which is composed of sodium nickel hexacyanoferrate (NaNiHCF) and sodium iron HCF (NaFeHCF) electrodes. In this system, ions are removed not only by charging steps but also by discharging steps, and it is possible to treat actual seawater with this system because the Prussian blue material has a high charge capacity with a reversible reaction of alkaline cations. Here, we demonstrate a rocking chair desalination battery to desalt seawater, and the results show that this system has a high desalination capacity (59.9 mg/g) with efficient energy consumption (0.34 Wh/L for 40% Na ion removal efficiency).

Switchable self-assembly of Prussian blue analogs nano-tiles triggered by salt stimulus

We showed fully reversible, ionic strength controlled self-assembly of Prussian blue analogues nano-tiles into large superlattice structures.

Mesocrystalline coordination polymer as a promising cathode for sodium-ion batteries

Prussian blue (PB) mesocrystals with Na as the alkaline metal were synthesized and used for as cathodes in Na-ion batteries. The mesocrystalline structure endowed PB with very different phase change behavior and electrochemical performance in contrast to PB single-crystals in cyclic voltammograms and galvanostatic discharge/charge voltage profiles of PB/Na half-cells.

Universal strategy for homogeneously doping noble metals into cyano-bridged coordination polymers

Coordination polymers with large surface areas and uniform but tunable cavities have attracted extensive attention because of their unique properties and potential applications in numerous fields. The introduction of noble metal into coordination polymers, which may enhance or display new behaviors beyond their parent counterparts, presents great challenges in maintaining the fragile coordination structures and meeting the compatibility. Here, cyano-bridged coordination polymers are robust and show very nice compatibilities with a series of noble metals, such as Pd, Pt, Au, Ag. Those noble elements partially take the place of the transition metal ions under room temperature (for Au and Ag) or a mild hydrothermal environment (for Pd and Pt) without damaging the framework. By using this universal simple synthetic procedure, we prepared a series of noble metal containing metal hexacyanoferrate (MHCF) with various morphologies and structures, including Pd/Pt/Ag/Au-MnHCF, Pd/Pt/Ag/Au-CoHCF, and Pd/Pt/Ag/Au-NiHCF. Among them, Pd-MnHCF demonstrates the control of morphologies by adjusting operational details, and notably, it shows very unique, enhanced catalytic performance, reflecting the superiority of cyano-connected positive-valent Pd as a single-atom catalyst.

A cyano-bridged copper(ii)–copper(i) mixed-valence coordination polymer as a source of copper oxide nanoparticles with catalytic activity in C–N, C–O and C–S cross-coupling reactions

A cyano-bridged Cu(ii)–Cu(i) complex was synthesized and transformed into CuO nanoparticles. Their catalytic activity in C–N, C–O, and C–S cross-coupling reactions was explored.