Phthalocyanine And Porphyrin With In-situ Synthesis On Nano-ZnO Surface And Their Photocatalytic Selectivities Under Visible Irrdiation

ZnO as a wide band gap(3.37eV)semiconductor materials is with high electron mobility and good biocompatibility,has been widely used in photocatalysis.However,due to its absorption of ultraviolet light range locates on UV range,and recombination for photo-generated charge is serious.And also,ZnO is without selective as a photocatalyst.So the surface of ZnO nanomaterials need to be sensitized to broaden the spectrum into light range and achieve selective photocatalysis.The modified ZnO nanomaterials with visible light absorption and high selectivity for photocatalysis is important.Herein,the conductive glass was induced in a high surface activity of the exposed surface of the nano-ZnO material.Zn ions with Zn-unsaturated coordination bonds on the surface of ZnO was used as a template,and also sulfo phthalonitrile,phenoxy phthalonitrile and pyrrole were used as "molecular fragments",respectively.Zinc phthalocyanine and porphyrin zinc were synthesized on the surface of ZnO by in-situ method.Zinc phthalocyanine/ZnO and porphyrin zinc/ZnO composites were obtained,improving its response characteristics of visible light,selective catalytic efficiency.Further,and the selective photocatalytic mechanism was investigated.The main contents and results are as follows:(1)The dumbbell-shaped morphology ZnO(ZnO ZDs)with side facet of(100)and cross-section facet of(001)on the surface of the conductive glass using a liquid phase precipitation method are highly active surface of ZnO nanomaterials.Sulfo phthalonitrile as a molecular fragment,Zn ions with dangling bonds on ZnO surface as a template,the four sulfo phthalocyanine zinc(ZnTsPc)molecules were synthesized by in-situ process.Compared to ZnO ZDs,ZnTsPc/ZnO composites show better hydrophilicity.Under visible light irradiation,methylene blue(MB)and phenol(PL)by ZnTsPc/ZnO illustrated better in degradation rate of 1.9 times and 1.1 times than ZnO ZDs,respectively.The photo-generated charges in ZnTsPc/ZnO were effectively separated under visible irradiation.In addition,the relative degradation rate in mixture of MB and PL by ZnTsPc/ZnO is 5,1 times for MB molecule to PL,exhibiting selective photocatalytic properties due to MB with hydrophilics.Based on ZnTsPc macrocycle with a hydrophilic group-sulfo group,a hydrophilic dye molecule,MB molecules,preferentially adsorb on the surface of ZnO,inducing higher photocatalytic degradation.(2)A four phenoxy phthalocyanine zinc(ZnTPPc)/ZnO with good surface hydrophobicity has been synthesized on the ZnO ZDs surface by in-situ method with DBU,showing high affinity for the PL molecule.Degradation rates for PL by ZnTPPc/ZnO were 84.2%and 84.6%of ZnO ZDs.In ithe mixture of MB and PL for ZnTPPc/ZnO photocatalytic experiments,the degradation rate by ZnTPPc/ZnO for PL molecules is 1.3 times to MB molecules,representing selective photocatalytic properties due to PL as lipophilic molecules.The mechanism for the photocatalytic selectivity for PL is corresponding to that ZnTPPc with week phenoxy lipophilic groups in the ring can selectively adsorb PL molecules.(3)Pyrrole and benzaldehyde as precursors,zinc tetraphenylporphyrin(ZnTPP)were in-situ synthesized on ZnO ZDs surface by Adler method.Under visible light irradiation,was used as a photocatalytist.Degradation rates for MB and PL by ZnTPP/ZnO were 2.1 and 1.4 times to ZnO ZDs,respectively.Meanwhile,in the experiments of photocatalytic for a mixture of MB and PL,the relative degradation rate for PL molecules by ZnTPP/ZnO was 1.83 times to that of MB molecule.According to the substituted group as a lipophilic group,phenyl group,in the peripheral ring of ZnTPP,PL molecules preferentially adsorbed on the surface of the composite,showing a better degradation rate than that of MB.