Effect of transition metal doping on crystallization of cloverite

Gallophosphate molecular sieves containing Mn, Co and Zn have been hydrothermally synthesized at 170 °C, using starting gels with transition metals, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), etc. Each starting gel yielded cloverite (CLO)-type phase, and its crystallinity depended on the kind of transition metal in the starting gel. The addition of a small amount of ZnO to the starting gel was observed to be useful for the preparation of Zn-doped cloverite (Zn-CLO) with good crystallinity, i.e. ZnO promoted crystal growth. The results of estimated unit cells and chemical analysis suggested that Mn²⁺ and Zn²⁺ ions were incorporated into the frameworks of Mn- and Zn-doped cloverites (Mn-CLo and Zn-CLO), respectively.