อิทธิพลของโลหะเจือต่อสมบัติทางแสงและการเร่งปฏิกิริยาด้วยแสงของอนุภาคซิงค์ออกไซด์เตรียมด้วยวิธีไฮโดรเทอร์มอล

Abstract

In this work, pure ZnO and metal doped ZnO were prepared by hydrothermal method at 180°C for 15 hours using KOH and CO(NH), as precipitants. The mole ratio (R) of PEO-b-PPO, to Zn(CH,COO),*2H2O and amount of nickel and cobalt contents were investigated. ZnO prepared by using KOH solution exhibited nanoplatelets structure and altered to form as flower-like structure when doping with nickel and cobalt. Besides, the secondary phases: B-Ni(OH), and B-Co(OH), form when doping with nickel and cobalt. These secondary phases were decomposed to NiO and Co,O,, respectively when being calcined at 800°C. On the other hand, ZnO prepared from CO(NH2), solution and calcined at 800°C exhibited mesh-like lamellae structure. ZnO did not change its shape when doping with nickel and cobalt. The optical properties showed that the pure ZnO can absorb UV light irradiation whereas nickel- and cobalt-doped ZnO can absorb UV irradiation and little visible light because the secondary phase caused a generation of band tail energy within the forbidden band of ZnO, giving rise to reduction of E. value. The photocatalytic activity showed that ZnO prepared from KOH solution at R = 0.75 exhibited the best photocatalytic activity in both UV and visible irradiation. Metal doped ZnO had lower photocatalytic activity than pure ZnO except at 6 mol% nickel doped ZnO prepared from KOH solution exhibited better photocatalytic activity under visivle light than pure ZnO.