Bottom-Up Assembly of Ni₂P Nanoparticles into Three-Dimensional Architectures: An Alternative Mechanism for Phosphide Gelation

The synthesis of Ni 2 P nanoparticle three-dimensional architectures using two different approaches is reported. The oxidation-induced sol–gel method involves chemical oxidation of surface phosphorus to form P–O–P linkages between particles in the gel network, similar to the mechanism originally reported for InP nanoparticles. The second method, metal-assisted gelation, occurs by cross-linking of pendant carboxylate functionalities on surface-bound thiolate ligands via metal ions to yield an interconnected particle network. The method of gel network formation can be tuned by changing the surface ligand terminal functionalities and the nature (oxygen-transferring or non-oxygen-transferring) of the oxidant. Both methods produce porous, high surface area materials with thermal stabilities above 400 °C.