Multi-shelled hollow materials (MSHMs) with multifunctional compositions and multilevel interiors have received great attention by virtue of their hierarchical hollow structures and diverse applications. In this contribution, we present a new synthetic protocol to fabricate binary MSHMs with up to quadruple shells through a rapid thermal process. The binary MSHMs contain hexagonal ZnO (the primary phase) and monoclinic CuO (the secondary phase), wherein, the ZnO phase was derived from the straightforward degradation of a coordination polymer (for example, dandelion-like amorphous ZIF-90 (a_mZIF-90)), and the CuO phase was derived from the preloaded copper nanoparticles on a_mZIF-90 which appear to enhance the oxidative degradation of a_mZIF-90. This protocol relies on the metal nanoparticle aided degradation of a_mZIF-90 in which the catalytic reactivity of metal was found in the order of Au < Co < Pt < Cu. Therefore, calcining a_mZIF-90/Au or a_mZIF-90 alone only led to the formation of nonhollow products. The number of layers in binary CuO/ZnO could be controlled by adjusting copper loading, annealing temperature, or heating ramp rate. Furthermore, the resultant binary CuO/ZnO MSHMs exhibited pronounced catalytic activity on the advanced oxidation process (AOP) toward dye wastewater treatment. This synthetic protocol may be employed for fabrication of other binary MSHMs from the enhanced oxidative degradation of ZIFs or their analogues.

中文翻译：

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二元多壳空心球的合成方法及其增强的氧化应用

具有多功能成分和多层内部结构的多壳空心材料（MSHM）凭借其分层的空心结构和多样化的应用受到了广泛的关注。在这项贡献中，我们提出了一种新的合成协议，可以通过快速热处理来制造具有多达四层外壳的二元MSHM。二进制MSHMs包含六角形的ZnO（主相）和单斜晶的CuO（第二相），其特征在于，所述氧化锌相从配位聚合物的直接的降解的（例如，蒲公英状无定形ZIF-90（一_米ZIF -90）），和CuO的相从上预加载的铜纳米颗粒衍生的一_米的ZIF-90中出现，以增强的氧化劣化一个_m ZIF-90。该方案依赖于金属纳米粒子辅助的_m ZIF-90降解，其中发现金属的催化反应性的顺序为Au <Co <Pt <Cu。因此，煅烧一_米的ZIF-90 /金或一_米的ZIF-90单独不仅导致nonhollow产物的形成。二元CuO / ZnO中的层数可以通过调整铜的负载量，退火温度或加热升温速率来控制。此外，生成的二元CuO / ZnO MSHMs在高级氧化工艺（AOP）上对染料废水的处理表现出明显的催化活性。该合成方案可用于由ZIF或其类似物增强的氧化降解来制造其他二元MSHM。