Ce掺杂ZnO纳米复合材料的制备及光催化性能研究

Preparation and photocatalytic performance ofCe doped ZnO nanocomposites

以ZnO作为光催化剂,稀土元素Ce为添加相,通过水热法制备了不同摩尔比Ce掺杂的ZnO纳米复合材料,以甲基橙(MO)染料为降解对象,研究了Ce掺杂摩尔比对ZnO纳米复合材料的晶格结构、微观形貌和光催化性能的影响。结果表明,制备的Ce-ZnO纳米复合材料均为六方晶系纤锌矿结构,外观为不规则的颗粒状,Ce掺杂后使ZnO的表面粗糙度增加。Ce掺杂后在ZnO中无新产物产生,没有影响ZnO的结构。随着Ce掺杂摩尔比的增大,Ce-ZnO的比表面积逐渐增大,吸收边先增大后减小,禁带宽度先降低后升高,光致发光强度先降低后增大。0.6%Ce-ZnO的比表面积达到33.91 m^(2)/g,吸收边最大为394 nm,禁带宽度最小为2.97 eV,对应的光致发光强度最低。光催化降解测试表明,随着Ce掺杂摩尔比的增大,Ce-ZnO对MO的光催化降解率先增大后降低,0.6%Ce-ZnO在180 min时对MO的降解率达到最大值95.36%。强酸或强碱条件下均不利于光催化反应的进行,在pH值=5的弱酸条件下0.6%Ce-ZnO对MO的降解率最高达到99.16%。0.6%Ce-ZnO光催化剂重复使用5次时对MO的降解率依旧超过70%,具有良好的使用稳定性和经济效益。

ZnO nanocomposites with different molar ratios of Ce doping were prepared by hydrothermal method using ZnO as a photocatalyst and rare earth element Ce as an additive phase.The effect of Ce doping molar ratio on the lattice structure,microstructure and photocatalytic performance of ZnO nanocomposites was studied using methyl orange(MO)dye as the degradation object.The results showed that the Ce-ZnO nanocomposites prepared were all hexagonal wurtzite structured with an irregular granular appearance.Ce doping increased the surface roughness of ZnO.After Ce doping,no new products were produced in ZnO,which did not affect the structure of ZnO.As the Ce doping molar ratio increased,the specific surface area of Ce ZnO gradually increased,the absorption edge first increased and then decreased,the bandgap width first decreased and then increased,and the photoluminescence intensity first decreased and then increased.The specific surface area of 0.6%Ce-ZnO reached 33.91 m^(2)/g,with a maximum absorption edge of 394 nm and a minimum bandgap width of 2.97 eV,corresponding to the lowest photoluminescence intensity.The photocatalytic degradation test showed that with the increase of Ce doping molar ratio,the photocatalytic degradation of MO by Ce-ZnO first increased and then decreased.The degradation rate of MO by 0.6%Ce-ZnO reached its maximum value of 95.36%at 180 min.Under strong acidic or alkaline conditions,it wasn t conducive to the progress of photocatalytic reactions.Under weak acidic conditions with a pH value of 5,the degradation rate of MO by 0.6%Ce-ZnO reached a maximum of 99.16%.When the 0.6%Ce-ZnO photocatalyst was reused for 5 times,the degradation rate of MO still exceeded 70%,indicating good usage stability and economic benefits.