pH-assisted crystallization of Cu2O: chemical reactions control the evolution from nanowires to polyhedra
pH-assisted crystallization of Cu2O: chemical reactions control the evolution from nanowires to polyhedra
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pH 辅助 Cu2O 结晶：化学反应控制从纳米线到多面体的演变
DOI：
10.1039/c2ce26084k
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发表时间：
2012-01-01
期刊：
影响因子：
3.1
通讯作者：
Xue, Dongfeng
中科院分区：
文献类型：
--
作者：
Chen, Kunfeng;Xue, Dongfeng
本工作报告的化学反应控制结晶的CuO与系统的形状演变从纳米线，通过纳米颗粒聚集的球体和八面体截短的八面体和cuboctahedra的两步“前体形成结晶”的过程。结果表明，pH依赖的前体物种Cu-2（OH）（3）NO3、Cu（OH）（2）和Cu（OH）（4）（2-）主要决定了产物的形状、尺寸、组成变化和反应机理.在溶液中加入一定量的OH-是调节还原和络合反应的关键，而还原和络合反应控制着Cu 2 O的结晶;高pH值增强了淀粉的还原能力和OH-的络合能力。由于还原反应的pH依赖性，Cu 2 O或Cu可以在碱性或酸性条件下选择性地结晶。结果表明，由于络合反应和氧化还原反应的竞争，截短八面体的尺寸随pH值的增加先增大后减小。结果表明，控制pH依赖的化学反应是调节氧化物结晶及其电化学活性的有效途径。
This work reports the chemical reaction-controlled crystallization of Cu2O with systematic shape evolution from nanowires, through nanoparticle-aggregated spheres and octahedra to truncated octahedra and cuboctahedra by a two-step "precursor formation-crystallization" process. The results reveal that the shape, size, composition variation and overall reaction mechanism were mostly determined by the pH-dependent precursor species Cu-2(OH)(3)NO3, Cu(OH)(2) and Cu(OH)(4)(2-). The addition of specific amounts of OH- to the solution is the key to adjusting the reduction and complexation reactions that control the crystallization of Cu2O; high pH enhanced the reducing power of starch and the complexation ability of OH-. Cu2O or Cu can be selectively crystallized under alkaline or acidic conditions due to the pH-dependence of the reduction reaction. The intriguing results show that the size of truncated octahedra first increases, then decreases with increasing pH owing to the competition between the complexation and redox reactions. The results demonstrate that control of pH-dependent chemical reactions is an effective way to adjust the crystallization of oxides and their electrochemical activity.