蒺藜状Cu掺Zn氧化物纳米颗粒的制备及表征

以Zn（NO3）2为前驱体、PVP为包覆剂，在碱性条件下掺杂Cu（NO3）2，制备800—2000nm量级的蒺藜状ZnO颗粒和ZnO／Cu（OH）：的复合物，蒺藜状ZnO颗粒由ZnO纳米片构成，Cu（OH）2纳米棒长约50nin，直径约15nm。Cu2＋的掺杂减小了ZnO／Cu（OH）2颗粒尺寸，Cu^2＋在复合纳米颗粒的生长中起催化作用。经500℃退火，ZnO／Cu（OH）。复合物转变为ZuO／CnO复合物，其中蒺藜状ZnO颗粒基本维持原貌，Cu（OH）2纳米棒转化成CuO纳米颗粒。对制备的微／纳米材料进行了XRD、TEM和UV—Vis表征，结果表明掺杂20％Cu^2＋时，ZnO／Cu（OH）2和ZnO／CuO复合纳米颗粒尺寸均匀、分散性好。退火前后ZnO颗粒在紫外可见区域均具有宽吸收带，带隙约为2．200eV和2．268eV，这与蒺藜状纳米颗粒独特的形貌导致表面大量。空位和Zn间隙有关。Cu^2＋的掺杂使ZnO的吸收谱变窄，ZnO／Cu（OH）2和ZnO／CuO复合纳米颗的带隙均大于纯ZnO的带隙，原因是Cu^2＋进入ZnO的晶格使。空位和Zn间隙减少，从而使导带向高能方向移动，电子跃迁宽度增大，带隙增大。

Under alkaline condition, tribulus shaped ZnO nanoparticles （NPs） and ZnO/Cu（OH）2 complex NPs with sizes of 800-2000 nm were prepared by taking Zn（NO3）2 as precursor, Cu（NO3）2 as doping agent （0-20%） and PVP as coating agent. The tribulus shaped ZnO NPs are composed of ZnO sheets. The Cu （OH）2 nanorods with length of 50 nm and diameter of 15 nm distribute on the ZnO sheets. The experimental results show that the sizes of the ZnO/Cu（OH）2 are smaller than that of ZnO NPs after doping Cu^2＋. The Cu^2＋ act as catalyst in the growth of . ZnO/Cu（OH）2 complex NPs. After annealing at 500 ℃ for 2 h, the ZnO/Cu（OH）2 NPs were changed into ZnO/CuO NPs. The tribulus shaped ZnO NPs were basically not changed but the tips of the ZnO sheets were smoothed. The Cu（OH）2 nanorods were changed into CuO NPs and dotted on the sheets of ZnO. When the doping concentration of Cu^2＋ is 20%, the ZnO/Cu （OH）2 and ZnO/CuO complex NPs have homogeneous shape and good dispersion. The ZnO NPs have wide absorption band in the range of UV-Vis even NIR. The band gaps of the ZnO NPs are 2.200 eV and 2.268 eV before and after annealing. Doping of Cu^2＋ narrows down the absorption band of ZnO NPs, and the band gaps of ZnO/Cu（OH）2 and ZnO/CuO are also larger than that of ZnO. The main reason is that Cu^2＋may enter into the ZnO nanosheets and decrease the O vacancy and Zn interstitial, which makes the conductor band move to the higher energy direction, the width of the energy transition increase, and the band gap increase.