Preparation,Characterization And Photocatalytic Properties Of （C-）M^2+,3+,4+/ZnO Spongelike Structure Nanomaterials

With using orange peel（OP）as the template and carbon source,three series of（C-）M^2+,3+,4+/ZnO spongelike structure materials were prepared by using template-assisted hydrothermal-calcination two-steps method without adding any alkali precipitant.The crystallization properties,morphology,specific surface area and carbon content and other properties of the target materials were characterized by some analytical techniques,such as XRD,BET,SEM and Vario EL cube.The photocatalytic activity of the target materials were evaluated by the degradation effect of high-concentration MB solution under 300 W high pressure Hg lamp（HPHL）.The specific research contents are as follows:（1）Three series of（C-）Cu²⁺/ZnO,（C-）Cr³⁺/ZnO and（C-）Sn⁴⁺/ZnO spongelike structuralphotocatalyticmaterialswerepreparedbytemplate-assisted hydrothermal-calcination two-steps method.The main material ZnO was modified by means of the presence of carbon,metal ions-doped and special morphology construction.The effects of the hydrothermal temperature（120²00℃）,hydrothermal time（5¹5 h）,calcination temperature（350⁷00℃）,the amount of doped ions（0.00⁰.05 at%）and the amount of template（0.0⁴.0 g）on the photocatalytic performance of the materials were investigated.The results show that the above conditions have different effects on the photocatalytic properties of the samples.Among these conditions,the amount of template plays the most important role on improving the photocatalytic performance of samples.The samples prepared without the templates showed no photocatalytic degradation ability for the high-concentration methylene blue solution,while the samples prepared with the templates showed good photocatalytic performance.（2）The C-M^2+,3+,4+/ZnO materials and M^2+,3+,4+/ZnO materials all have special spongelike morphology.The spongelike morphology can not only greatly increase the specific surface area of the samples,provides more adsorption and activation sites for the reactant molecules,but also improve the utilization of light through the process of multiple absorption-reflection-reabsorption of light.So the photocatalytic properties of the（C-）M^2+,3+,4+/ZnO materials were improved.Metal ions-doped in C-M^2+,3+,4+/ZnO materials and M^2+,3+,4+/ZnO materials can introduce doping levels.On the one hand,the doping levels can provide more transition pathways for photogenerated electrons.On the other hand,doping levels could greatly reduce the energy required for photogenerated electron transition.Therefore,doping metal ions in ZnO can improve the photocatalytic activity of the samples.The carbon contained in samples can effectively inhibit the recombination of photogenerated electron-hole pairs,so the quantum yield of the samples is improved.Therefore,the photocatalytic performance of C-M^2+,3+,4+/ZnO materials are generally better than those of M^2+,3+,4+/ZnO materials.（3）By comparing the decolorization effects of high-concentration MB solution on all samples,it can be concluded that the existence of carbon and metal ions-doped and the special morphology construction play a synergistic role in improving the photocatalytic activity of target materials.According to the photocatalytic results that the best materials are（C-）Sn⁴⁺/ZnO,and the（C-）Cu²⁺/ZnO materials take the second place,and the（C-）Cr³⁺/ZnO materials are relatively poor.This result may be due to the different similarities of valence electron configuration between different metal doped ions with Zn²⁺.The valence electron configuration of Zn²⁺,Sn⁴⁺,Cu²⁺and Cr³⁺are d¹⁰,d¹⁰,d⁹ and d³,respectively.The valence electron configuration of Sn⁴⁺is similar with Zn²⁺,and the（C-）Sn⁴⁺/ZnO materials have higher photocatalytic activity.