Preparation of mesoporous nanocrystalline cerium phosphate with controllable pore size by using chelating agent

Abstract

A considerably high surface area of nanocrystalline mesoporous cerium phosphate with controllable pore size has been obtained by using N-(2-hydroxyethyl)-ethylenediane- N, N′, N′-triacetic acid (H 3hedtra) as chelating agent. By varying the mole ratio of H 3hedtra/Ce during synthesis, the surface area and average pore size of the materials as well as narrow pore size distribution can be controlled properly. The highest surface area of the obtained cerium phosphate is 145 m 2 g −1 with average pore size at 8.54 nm, which is significantly higher than that of the reference sample prepared without H 3hedtra. The morphology of the samples was observed by using TEM where sample prepared in the presence of H 3hedtra possessed relatively smaller particle size compared with the reference sample prepared without H 3hedtra. Besides, higher amount of acidic sites was found for samples prepared in the presence of H 3hedtra compared with the sample prepared free of H 3hedtra. Although the acid strength remained unchanged, the surface concentration of acidic sites had increased at mole ratio of H 3hedtra/Ce above 0.5.