One-step, template-free route to silver porous hollow spheres and their optical property

Silver porous hollow spheres (SPHS) were fabricated via ultrasonic spray pyrolysis of aqueous solutions containing AgNO3 and glucose. In the hot spherical liquid droplets, glucose, as reducing agent, reacted with Ag+ to form Ag nanoparticles, which subsequently moved to the periphery of the hot liquid droplets to form Ag nanoparticles–glucose hybrid shell. With the temperature further increased, aforementioned Ag nanoparticles melted to form Ag skeleton decorated with unreacted glucose, which converted to SPHS via dissolving unreacted glucose in water. Due to their porous hollow structures, SPHS exhibited a wide Vis–NIR adsorption in the range of 400–1100 nm.