Sonochemical synthesis of porous Cu₂O–Cu hollow spheres and their photo-catalysis

Porous Cu₂O–Cu hollow spheres were successfully synthesized by a facile, one-pot and green method with assistance of ultrasonic technique. By prolonging ultrasonic irradiation time, the solid spheres of Cu₂O transformed into core–shell structure, then into hollow spheres, which accompanied with composition shift. XRD, FE-SEM, TEM, EDX and XPS were used to investigate the structural and composition transformation of the products. Finds indicated that the formation of Cu₂O–Cu hollow spheres was caused by the sacrificial template-directed chemical transformation from Cu₂O to Cu and the re-crystallization of Cu₂O on the shell based on Ostwald ripening effect together. Furthermore, Cu₂O–Cu hollow spheres with rough surface and available pores exhibited excellent adsorption ability and better photo-catalytic activity for the degradation of methyl orange compared to other structures. - Highlights: • A facile, one-pot route was developed to fabricate Cu₂O–Cu hollow spheres. • The structural and composition evolutions of spheres were observed. • Cu₂O–Cu hollow spheres exhibited excellent adorability and photocatalytic activity