Encapsulation method for the dispersion of NiO onto ordered mesoporous silica, SBA-15, using polyethylene oxide (PEO)

An effective method for dispersing NiO onto ordered mesoporous silica, SBA-15, is described. The procedure involves the use of polyethylene oxide (PEO) as an encapsulating agent. It can be expected that encapsulation between PEO and Ni²⁺ ions mainly involves complexes between PEO and Ni ²⁺ ions. Both N₂ adsorption/desorption isotherm and TEM analyses indicate that a 2-dimensionally hexagonal pore structure with a distinct pore symmetry (space group P6mm) is maintained throughout the procedure, even though both Ni²⁺ ions and PEO are present in the middle of the self-assembly of mesostructured silica. The particle size of the NiO increases slightly as a function of PEO concentration. When the ratio of PEO to the templating agent (triblock copolymer, polyethylene oxide-polypropylene oxide-polyethylene oxide) reaches a value of 4.5, ordered mesoporous silica with NiO is hardly formed.