A special Cu(NO₃)₂ thin solution layer was built on highly hydrophilic mica surfaces and subjected to rapid evaporation. Controlling the evaporation time can intentionally manipulate the supersaturation. Morphology-selective synthesis of nanoplate- or microsphere-like Cu(NO₃)₂·2.5H₂O micro/nanostructures has been succeeded by alternatively boosting either the heterogeneous nucleation at the substrate–solution interface at a low supersaturation level or the homogeneous nucleation in the bulk solution phase at a high supersaturation level. Our study presents a new method for morphology-selective synthesis of micro/nanostructures, which should also be applicable to materials other than Cu(NO₃)₂·2.5H₂O and shall actually promote their applications. As a demonstration, Cu(NO₃)₂·2.5H₂O micro/nanostructures were converted into porous CuO with well-preserved starting morphologies. The hierarchical porous CuO micro/nanostructures exhibited easily recyclable high photocatalytic activity towards visible-light degradation of methylene blue (MB).

中文翻译：

---

通过合理地控制成核途径实现了 Cu（NO ₃）₂ ·2.5H ₂ O微观/纳米结构的形态选择性合成，并将其形态保留为CuO多孔微观/纳米结构†

在高度亲水的云母表面上构建了特殊的Cu（NO ₃）₂稀溶液层，并进行了快速蒸发。控制蒸发时间可以有意地控制过饱和。纳米板状或微球状Cu（NO ₃）₂ ·2.5H ₂ O微观/纳米结构的形态选择性合成已经成功地通过以低过饱和度或均匀成核的方式增强了底物-溶液界面处的非均相成核来实现。处于高过饱和水平的本体溶液相中。我们的研究提出了一种微观/纳米结构的形态选择性合成的新方法，该方法也应适用于除Cu（NO _3）以外的其他材料。）₂ ·2.5H ₂ O并应实际推广其应用。作为演示，将Cu（NO ₃）₂ ·2.5H ₂ O的微观/纳米结构转化为具有良好保留的起始形态的多孔CuO。分层的多孔CuO微观/纳米结构对亚甲基蓝（MB）的可见光降解表现出易于回收利用的高光催化活性。