Efficient removal of Cr(VI) from water represents one of the hotspots in global environmental protection. Herein, three isostructural polyoxometalate-thiacalix[4]arene-based coordination materials, namely [Mn₂L₂(H₂O)₂][H₃Mn₄PW₁₀O₄₀]·2C₂H₅OH·4H₂O (1), [Cd₂L₂(H₂O)₂][H₃Cd₄PW₁₀O₄₀]·C₂H₅OH·3H₂O (2) and [Ni₂L₂(H₂O)₂][H₃Ni₄PW₁₀O₄₀]·2C₂H₅OH·5H₂O (3), were prepared under solvothermal conditions (L = tetra-(2-mercaptopyridine 1-oxide)-thiacalix[4]arene). Single-crystal X-ray diffraction analysis showed that they featured rarely reported four-substituted M₄PW₁₀ (M = Mn(II), Cd(II), or Ni(II)). These coordination compounds were employed as efficient photocatalysts for Cr(VI) reduction without the addition of sacrificial agents. The experimental results indicated that 1 possessed the highest photocatalytic activity. The influence of the energy band structure of the photocatalyst on Cr(VI) reduction was also explored. Furthermore, the Bi₂WO₆/1 composite material was successfully prepared. The optimized Bi₂WO₆/1 photocatalyst (80Bi₂WO₆/1) exhibited a remarkably efficient photocatalytic activity, reducing 91% of Cr(VI) within 20 min. This research provides a perspective for the design and application of the polyoxometalate-thiacalix[4]arene-based photocatalysts in the treatment of environmental pollutants.

中文翻译：

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一系列四取代多金属氧酸盐-硫杂硅[4]芳烃基材料用于高效光催化还原 Cr(VI)

高效去除水中Cr( VI )是全球环境保护的热点之一。本文中，三种同结构多金属氧酸盐-硫杂杯[4]芳烃基配位材料，即[Mn ₂ L ₂ (H ₂ O) ₂ ][H ₃ Mn ₄ PW ₁₀ O ₄₀ ]·2C ₂ H ₅ OH·4H ₂ O( 1 )、[Cd ₂ L ₂ (H ₂ O) ₂ ][H ₃ Cd ₄ PW ₁₀ O ₄₀ ]·C ₂ H ₅ OH·3H ₂ O( 2 )、[Ni ₂ L ₂ (H ₂ O) ₂ ][H ₃ Ni ₄ PW ₁₀ O ₄₀ ]·2C ₂ H ₅ OH·5H ₂ O ( 3 )，在溶剂热条件下制备（L = 四-(2-巯基吡啶 1-氧化物)-thiacalix[4]芳烃） 。单晶X射线衍射分析表明，它们具有罕见报道的四取代M ₄ PW ₁₀（M = Mn( II )、Cd( II ) 或Ni( II )）。这些配位化合物被用作有效光催化剂，无需添加牺牲剂即可还原Cr( VI )。实验结果表明1具有最高的光催化活性。还探讨了光催化剂能带结构对Cr( VI )还原的影响。此外，还成功制备了Bi ₂ WO ₆ / 1复合材料。优化后的Bi ₂ WO ₆ / 1光​​催化剂（80Bi ₂ WO ₆ / 1）表现出非常高效的光催化活性，在20分钟内还原了91%的Cr( VI )。该研究为多金属氧酸盐-硫代杯[4]芳烃基光催化剂在环境污染物处理中的设计和应用提供了前景。