Shankar M V, Anandan S, Venkatachalam N, Arabindoo B, Murugesan V
Department of Chemistry, Anna University, Chennai, Tamil Nadu 600 025, India.
Chemosphere. 2006 May;63(6):1014-21. doi: 10.1016/j.chemosphere.2005.08.041. Epub 2005 Nov 10.
Zeolites HY, Hbeta and HZSM-5 with different physico-chemical properties were chosen as support for TiO2 to illustrate their adsorption, dispersion and electronic structure in photocatalysis. The extent of TiO2 loading was monitored by XRD and BET surface area measurements. The adsorption capacity of HY zeolite was found to be high and hence chosen for further modification to continue the investigation. Photodegradation kinetics were carried out with 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution. The extent of 2,4-D degradation on TiO2/HY loading revealed the importance of adsorption in photocatalysis. Mineralisation studies on all three zeolites with 1 wt.% TiO2 loading demonstrated the good dispersion properties of TiO2/HY. Its photocatalytic activity was found to be excellent with formulated 2,4-D. Comparison of relative photonic efficiencies demonstrated that supported photocatalysts exhibited higher activity than some of the commercial photocatalysts. The high activity of supported TiO2 is due to synergistic effects of improved adsorption of 2,4-D and efficient delocalisation of photogenerated electrons by zeolite support.
选择具有不同物理化学性质的HY、Hβ和HZSM-5沸石作为TiO₂的载体，以说明它们在光催化中的吸附、分散和电子结构。通过XRD和BET表面积测量来监测TiO₂的负载量。发现HY沸石的吸附能力较高，因此选择对其进行进一步改性以继续研究。在水溶液中用2,4-二氯苯氧乙酸（2,4-D）进行光降解动力学研究。TiO₂/HY负载上2,4-D的降解程度揭示了吸附在光催化中的重要性。对所有三种负载1 wt.% TiO₂的沸石进行矿化研究，证明了TiO₂/HY具有良好的分散性能。发现其对配制的2,4-D具有优异的光催化活性。相对光子效率的比较表明，负载型光催化剂表现出比一些商业光催化剂更高的活性。负载型TiO₂的高活性归因于2,4-D吸附改善和沸石载体对光生电子有效离域的协同效应。
