Improved visible-light-driven photocatalytic activity of CeO2 microspheres obtained by using lotus flower pollen as biotemplate

Porous CeO2 spheres were fabricated through mineralizing lotus flower pollen template via a cerium nitrate infiltration. The resulting products were characterized by FESEM, HRTEM, XRD, nitrogen adsorption, and UV–vis diffuse reflectance spectroscopy. The as-prepared photocatalyst exhibited a large surface area and multiple pore size distribution, which could effectively increase the reaction area and allow better catalytic capability. Surface oxygen activity was enhanced for the biomorphic ceria spheres, as was revealed by XPS measurements. The formation mechanism of hierarchical cerium dioxide microspheres was proposed. Moreover, the synthesized ceria shows high photocatalytic activity and exhibits remarkable ability to remove methylene blue under solar irradiation, suggesting they are promising photocatalyst for wastewater treatment.