Preparation And Photocatalytic Propertiy Study Of Porous ZnO Nanorod Array

A ZnO nanorod?NR?array has a great potential in the many field due to their unique photoelectric properties.A ZnO nanorod?NR?array grown on a substrate by a wet chemical method usually exhibits a smooth surface which cannot adsorb a large amount of pollutant molecules,the photocatalytic activity of ZnO is still not promoted effectively.In view of smaller surface area and less adsorption location of ZnO nanorod array,porous ZnO NR array on FTO conductive glass is successfully fabricated using a two-step wet chemical route.The photocatalytic properties are also discussed.The conclusions could be summarized as follows:?1?The porous structure with dense distribution has been introduced into the{1010}plane of the ZnO NR array via a facile chemical bath method mediated by cadmium?Cd?ions and subsequent calcination.The average diameter of the pores is21.3 nm.It is found that ZnO NR array is monocrystalline/polycrystalline composite structure and Cd ions are not doped into ZnO lattice.It is found that Cd ions can react with NH₃ molecules and OH^-ions in the growth solution to form Cd complexes and prefer to adsorb on the neutral{1010}surface of ZnO NRs.At the same time,Cd ions turn Zn?OH?₄^2-near the{1010}surface of ZnO NRs into Zn?OH?₄^2-and Zn complex.This will probably cause the formation of[Zn?C₂H₃O₂?₂?C₂H₈N₂?],which can be decomposed into ZnO nanoparticles after calcination,leading to the production of pores on the{1010}surface of ZnO NRs.?2?Investigation into CdSO₄ concentration and reaction temperature on morphology and size of porous ZnO NR array.The rod length,density and uniformity of films are increased with the Cd ions concentration increased.The distribution of the pores on the lateral facets of NRs also becomes sparser.Besides,the length and pore distribution on the{1010}surface of ZnO NRs changed with the reaction temperature increased.The size and morphology of the rods are optimal when the reaction temperature is 80°C.The length and aspect ratio of the rod are2.316?m and 14.76 respectively,pore distribution is also dense in this sample.?3?Porous ZnO NR array have better photocatalytic properties by photocatalytic degradation for Methylene blue?MB?under ultraviolet lamp.When introduced Cd ions,the ZnO thin films provide more stable adsorption sites for theadsorption of MB due to the formation of pores on the{1010}plane and increased aspect ratio of nanorods.So the filims have better photocatalytic activity.The optimal combination obtaining the best photocatalytic activity is 1 mM Cd ions and reaction temperature of 80°C.The size of the ZnO NR array is greatly influenced by the solvent.The addition of ethylene glycol in the growth solution makes NR array become relatively sparse and aspect ratio improved.When volume ratio of deionized water an dethylene glycol is 5,the aspect ratio of films are increased with the Cd ions concentration increased,pores are also formed.So the photocatalytic activities are improved.