Hierarchically porous metastable β-Ag2WO4 hollow nanospheres: controlled synthesis and high photocatalytic activity
Hierarchically porous metastable β-Ag2WO4 hollow nanospheres: controlled synthesis and high photocatalytic activity
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DOI：
10.1088/0957-4484/24/16/165602
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发表时间：
2013-04
期刊：
影响因子：
3.5
通讯作者：
Xuefei Wang;Can Fu;Ping Wang;Huogen Yu;Jiaguo Yu
中科院分区：
文献类型：
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作者：
Xuefei Wang;Can Fu;Ping Wang;Huogen Yu;Jiaguo Yu
亚稳态材料由于具有不同于热力学稳定相的独特的物理化学性质而受到广泛的关注。然而，由于纯亚稳材料很容易转变成相应的稳定相，所以目前报道的亚稳材料的种类仍然非常有限，难以有效地合成纯亚稳材料。因此，探索具有新颖和迷人功能的新型亚稳材料是非常重要的，也是一个巨大的挑战。本研究首次在聚甲基丙烯酸(PMAA)存在下，通过AgNO3和Na2WO4的快速沉淀反应，制备了直径为50-500 nm的β-Ag2WO4中空多孔纳米球。结果表明，PMAA不仅提供了一个球状的软模板来诱导中空纳米球的形成，而且还起到了抑制从热力学不稳定的β-Ag2WO4相向稳定的α-Ag2WO4相转变的作用。亚稳的β-Ag2WO4中空纳米球具有较大的比表面积(165.5 m2 g−1)，这是因为它具有层次化的多孔结构(微孔、中孔和大孔)，因此对甲基橙和苯酚水溶液的分解具有很高的光催化性能。本工作可为新型介稳中空材料的智能设计和制备提供一些新的思路，所制备的亚稳β-Ag2WO4中空纳米球在化学反应器、药物载体、太阳能电池、催化和分离纯化领域具有广泛的潜在应用。
Metastable materials have received extensive attention due to their unique physical and chemical properties which are different from those of the thermodynamically stable phase. However, the variety of reported metastable materials is still very limited owing to difficulties in the effective synthesis of pure metastable materials because they can easily transform into the corresponding stable phases. Therefore, it is crucial and a great challenge to explore new metastable materials with novel and fascinating functions. In this study, hierarchically porous metastable β-Ag2WO4 hollow nanospheres with a diameter of 50–500 nm were prepared for the first time by a facile precipitation reaction between AgNO3 and Na2WO4 in the presence of poly(methacrylic acid) (PMAA). It was found that the PMAA not only provided a spherical soft template to induce the formation of hollow nanospheres but also worked as an inhibitor to prevent the phase transformation from thermodynamically unstable β-Ag2WO4 to stable α-Ag2WO4 phase. The resultant metastable β-Ag2WO4 hollow nanospheres show a larger specific surface area (165.5 m2 g−1) owing to the hierarchically porous structure (micropores, mesopores, and macropores), resulting in a high photocatalytic performance for the decomposition of methyl orange and phenol aqueous solutions. The present work can provide some new insight into the smart design and preparation of other new metastable hollow materials, and the prepared metastable β-Ag2WO4 hollow nanospheres have various potential applications in chemical reactors, drug-delivery carriers, solar cells, catalysis, and separation and purification fields.