ZnO纳米丛的制备及其光催化性能研究

以沉淀法制备了高活性ZnO纳米丛(nanobushes,ZNB),以水热反应制备得到普通ZnO纳米颗粒(nanoparticles,ZNP).利用X射线衍射仪(XRD)、透射电镜(TEM)、扫描电镜(SEM)、比表面积测定仪(BET)和光致发光光谱(PL)等手段对ZNB和ZNP进行了表征,并比较了其光催化活性的差异.在紫外光(λ≤387 nm)照射40 min后ZNB使有机染料罗丹明B(Rhodamine B,RhB)完全褪色,而相同条件下ZNP仅能使RhB褪色53%.通过总有机碳(TOC)的测定,研究了ZnO对RhB深度氧化矿化程度,光照6 h后ZNB对RhB矿化率高达92%,而ZNP对RhB的矿化率只有77%.跟踪测定了光催化降解过程中活性氧化物种相对含量的变化,表明紫外光激发条件下,ZnO光催化反应机理主要涉及羟基自由基(.OH)历程,且ZNB产生活性氧化物种的量高于ZNP.

Preparation and photocatalytic acitivity of ZnO nanobushes

In this article,ZnO nanobushes(ZNB) with high photocatalytic activity were obtained by precipitation method,and regular ZnO nanoparticles(ZNP) were prepared by hydrothermal method.The prepared ZnO samples were characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,the Brunauer-Emmett-Teller and photoluminescence spectroscopy.Under UV irradiation(λ≤387 nm),ZNB showed a better photocatalytic acitivity than ZNP,which only degraded 53% rhodamine B(RhB) in 40 min,while the former degraded it completely.The measurement of total organic carbon(TOC) showed that 92% RhB was mineralized in 6 h by ZNB,but only 77% by ZNP.Reactive oxygen species was detected by horseradish peroxidase spectro-photometry and benzoic acid flurescence.The results indicated that ZnO photocatalytic mechanism involved hydroxyl radicals,and ZNB produced more reactive oxygen species than ZNP.Degradation of 2,4-dichlorophenol(2,4-DCP) under UV irradiation was also used to test the photocatalytic activity of ZNB and ZNP.