Use of Sol−Gel Chemistry for the Preparation of Cyanogels as Ceramic and Alloy Precursors

Abstract

The reaction of aqueous solutions of K2PdCl4 and K3Co(CN)6 results in gellike polymeric materials, characterized by bridging cyanides between the central metals of the adducts. These materials tend to be rigid in nature but contain in excess of 95% water by weight. We refer to these novel transition metal based hydrogels as cyanogels. In contrast to classic inorganic hydrogels these materials are not based on an oxide network. Dehydration of the cyanogels results in amorphous xerogels which maintain the initial polymeric structure of the cyanogel. Thermal processing of gels containing palladium and cobalt centers under an inert atmosphere at temperatures between 200 and 500 °C, produces a new metastable material. Sintering between 500 and 1000 °C produces ferromagnetic alloys, while processing under oxygen in the same temperature region gives the ceramic mixed oxide material PbCoO2, having the delafossite structure.

Cyanogel‐Derived Formation of 3 D Nanoporous SnO2–MxOy (M=Ni, Fe, Co) Hybrid Networks for High‐Performance Lithium Storage

“…[35][36][37][38][39][40][41] The elegance of cyanogels as precursors for alloys and metal oxides lies in their unique structural characteristics in terms of 3 D nanoporous framework, uniform distribution of metal species on the backbone, and so forth. Cyanogels, pioneered by Bocarsly et al, are 3 D cyanidebridged coordination polymers formed through the reactions of chlorometalates (R = Pt, Pd, Sn, etc.)…”

“…Moreover, the anodic performance of the 3 D nanoporous SnO 2 -NiO hybrid network was examined as a proof-of-concept demonstration of its compositional and structural superiorities in terms of lithium storage. [38] After annealing, the metal species in the Sn-M xerogels could be oxidized into metal oxides, and the 3 D nanoporous nature of the cyanogel precursors is well retained in the final products; this results in 3 D nanoporous SnO 2 -M x O y hybrid networks. Figure 1 depicts a schematic illustration of the construction of the 3 D nanoporous SnO 2 -M x O y hybrid networks.…”

Catalytic ammonolytic sol–gel preparation of a mesoporous silicon aluminium nitride from a single-source precursor

“…The sol-gel technique is an attractive approach for preparing micro/ mesoporous oxide materials as powders, membranes and filters with high purity and homogeneity due to its flexibility and low temperature preparation of sols and gels [3]. A number of sol-gel processes to prepare highly porous nonoxide ceramics have also been reported, e.g., boron nitride [4][5][6][7][8], metal (carbo)nitrides [9][10][11][12][13][14], silicon carbonitride [15][16][17][18][19][20][21] and boron carbonitride [22,23]. A sol-gel process in an ammono-system has been used to prepare polymeric boron-, titano-and tantalo-silazanes by controlled co-ammonolysis of the elemental alkylamides [24].…”

Low-temperature graphene growth using epochal catalyst of PdCo alloy

“…The lattice parameter of PdCo alloy at room temperature was 3.88 Å , larger than 3.83 Å of Pd 2 Co alloy. 18,19 This value increased to a maximum value of 3.93 Å at 400 C and decreased further as the temperature increased. On the other hand, the change of the lattice parameter of Ni(111) direction was almost negligible.…”