Zinc hydroxyapatite catalyst for decomposition of 2-propanol

Hydroxyapatite (HAp) is attracting interest as a heterogeneous catalyst due to its "zeolitic" properties that allow tailoring of chemically active surface sites for specific applications. Here, the crystallographic modification of HAp through incorporation of zinc (Zn²⁺) was studied using diffraction and spectroscopic techniques. The preferential displacement of tunnel calcium (Ca²⁺) by covalently bonded Zn²⁺ inhibits crystal growth and promotes the retention of an amorphous (10-20 wt%) component. In combination, these factors create chemically active surfaces that allow Zn-HAp materials to effectively absorb carbon monoxide (characteristic vibration at ∼1711 cm^-1) and catalyze the decomposition of 2-propanol.