Dual lanthanide role in the designed synthesis of hollow metal coordination (Prussian Blue analogue) nanocages with large internal cavity and mesoporous cage

Abstract

Prussian Blue (PB) analogue metal coordination nanocages comprised of mesoporous walls (ca. 3.5 nm pore width) encapsulating a cavity approaching ca. 100 nm in diameter (surfactant free) are presented as an advance in rational metal coordination polymer nanostructure design. The synthesis employs lanthanide ions (Gd(3+) or Er(3+)) which function initially as peripheral coordination crosslinkers of metallo-surfactant templated miniemulsion droplets, and, subsequently, as promoters in the removal of the organic component of those surfactants via metal-assisted ester hydrolysis. The success of this synthetic strategy relies entirely on the periphery coordination event occurring prior to the ester hydrolysis surfactant removal step. Crucially, this one-pot sequential synthesis was achieved using a newly developed metallo-surfactant designed to have a reduced ester hydrolysis rate. Syntheses of this innovative metallo-surfactant, intermediary PB analogue coordination polymer organo-nanoshells and the subsequent conversion to hollow metal coordination nanocages are fully characterised using a wide variety of techniques, including TEM, SEM, EFTEM, EDX, TGA, WAXD, NMR, N(2) adsorption, etc., and represent the first designed synthesis of hollow metal coordination nanocages containing a large nanoscale cavity (wall of hollow nanosphere is mesoporous; hence nanocage).

Hollow Structures Based on Prussian Blue and Its Analogs for Electrochemical Energy Storage and Conversion

“…Gd-Fe sphere [73] Fe-Fe box [74] Fe-Fe cube HCl etching Fe-Fe box [81] [82] In this type of strategies, the inhomogeneous distribution or different thermodynamic stability of the components within the as-formed PB/PBA templates or between the precursors and final products is the key factor for the core dissolution and thus the precondition for the formation of hollow structures.…”

“…[10] Regarding the PB or PBA materials, the O/W emulsions are usually employed to construct the hollow structures due to the hydrophilicity of the cyanide precursor, otherwise solid materials would be obtained if adopting the W/O ones. The researchers termed this process as "miniemulsion periphery polymerization (MEPP)," by which variable size [72] and composition [73] of PB or PBA hollow spheres can also be obtained. [72] Specifically, they used toluene and hexadecane as the oil phase to mix with water to form O/W emulsions.…”

Graphene-induced tiny flowers of organometallic polymers with ultrathin petals for hydrogen peroxide sensing

“…Hybrid flowers combine the advantages of both components including flexibility of polymers and catalytic performance of inorganic metal species, generating new and desirable functions. This enables them to meet the overall requirements for engineering applications such as superior catalytic performance together with acceptable mechanical strength and stability for biosensors [12][13][14][15][16][17][18][19][20][21][22][23][24]. Moreover, synthesis of hybrid flowers is crucial for fundamentally understanding the correlation among composition, structure and property of nanomaterials.…”

Large-scale synthesis of organometallic polymer flowers with ultrathin petals for hydrogen peroxide sensing

“…While polymer/PB hybrid nanoparticles with varied morphologies including nanoshells, nanocubes, vesicles, and nanoribbons have been reported, [33][34][35][36][37][38][39][40][41][42][43][44][45] the large-scale synthesis of polymer/PB hybrid flowers is unprecedented to the best of our knowledge. Crystalline polyethylene terminated with the cyanoferrate complex (PE-Fe) was allowed to crystallize in a concentrated solution (2.0 mg mL −1 ).…”