Dawson型多金属氧酸盐-双氢氧化物超薄膜的合成

Synthesis of Layered Double Hydroxides Ultra Thin Films Functionalized with Dawson-Type Polyoxometalate

通过层接层方法制备了基于剥离的锌钛双氢氧化物单层和典型的Dawson型多金属氧酸盐阴离子α-P_2W_(18)O_(62)^(6-)(P_2W_(18))间作用的新型超薄膜.采用UV/DRS、XRD、FT-IR、ICP-AES和SEM方法对样品的结构和形貌进行了表征.结果表明,P_2W_(18)的结构在超薄膜中未发生改变,超薄膜的厚度在纳米范围,表面形貌完整有序均匀.以制备的超薄膜为光催化剂测试了对偶氮类染料刚果红(CR)的可见光催化降解活性.超薄膜表现出比纯Dawson型多金属氧酸盐阴离子高得多的催化活性,主要归因于剥离的锌钛双氢氧化物单层和金属氧酸盐阴离子的强化学作用对其可见光光响应能力的提高.

The novel ordered ultra thin films （UTFs）based on the hybrid assembly of exfoliated Zn-Ti layered double hydroxide （LDH）monolayer and typical Dawson-type polyoxometalate （POM）anions α-P2W18O62 （P2W18） were pre- pared by utilizing the layer by layer （LBL）technique. The UTFs were characterized by UV diffuse reflectance spec- tra（UV/DRS）, X-ray diffraction （XRD）, Fourier transform infrared spectra （FT-IR）, inductively coupled plasma atomic emission spectrometry （ICP-AES）, and scanning electron microscopy （SEM）. The results indicate that the Dawson structures remained intact in the hybrid compositions, the thickness of the UTFs was within nano range, and the morphology was continuous and uniform. The visible light photocatalytic activities of the UTFs were tested in the degradation of aqueous azo dye Congo red （CR）. The UTFs showed much higher photocatalytic activity than pure P2W18, which was mainly attributed to the improved response ability of P2Wl8 to the visible light caused by the inter- action between exfoliated Zn-Ti-LDH monolayer and P2W18.