Preparation and enhanced visible light-driven catalytic activity of ZnO microrods sensitized by porphyrin heteroaggregate

An inorganic–organic composite (ZnO/TAPPI–CoTPPS) composed of ZnO microrods and nano-heteroaggregates containing tetrakis(4-trimethylaminophenyl) porphyrin (TAPPI) and tetrakis(4-sulfonatophenyl) porphyrin cobalt(II) (CoTPPS), has been achieved by a simple mixing method. From the solid diffuse reflectance UV–vis spectrum of ZnO/TAPPI–CoTPPS, it can be observed that the Soret band of the porphyrin heteroaggregate of ZnO/TAPPI–CoTPPS is blue-shifted in comparison with that of the pure TAPPI–CoTPPS heteroaggregate while the Q bands are red-shifted, which demonstrates that there exists some interaction between the porphyrin heteroaggregate and ZnO. In addition, the photodegradation of rhodamine B (RhB) in water catalyzed by ZnO/TAPPI–CoTPPS was investigated at room temperature. Under visible light irradiation (λ ≥ 420 nm), the photocatalytic activity of the ZnO/TAPPI–CoTPPS composite was higher than those of the porphyrin monomers modified ZnO composite and pure ZnO.