Chemical surface and electrochemical characterization of zirconium phosphate heterostructures

This work studies the structural and chemical modifications of functionalised porous phosphate heterostructures (PPH) of zirconium phosphate. The modification consists in incorporation of propionitrile at two different percentages, but pressure was also applied in order to obtain pressurized discs. The application of pressure (4 T cm2) provokes a migration of nitrile groups to the surface as observed by XPS analysis and it seems to be responsible for the drastic porosity decrease obtained by N2 adsorption. Electrochemical characterization of the pressured-discs in contact with NaCl solutions at different concentrations was also carried out. These results show the cation exchange capacity of PPH, which is slightly reduced in the case of the functionalised materials with nitrile groups (10% lower cation transport number), while diffusional permeability and electrical resistance values also confirm structural changes for the modified materials.