This study has been undertaken to investigate the UV irradiation effect on catalytic activities in Pd-catalyzed cross coupling reactions. A Pd-TiO₂-CNT composite was prepared by a previously reported sol-gel method, whereby anatase TiO₂ and metallic Pd nanoparticles were deposited onto the surface of carbon nanotubes (CNTs). The average particle size of these nanoparticles was determined to be ∼4.3 nm by transmission electron microscopy. The prepared Pd-TiO₂-CNT material was employed as a catalyst for the Heck and decarboxylative coupling reactions, and it showed higher catalytic activity in the presence of UV irradiation than in the absence of UV irradiation. The enhanced catalytic activity of this system can be explained by the increased nucleophilicity of Pd due to electron transfer from TiO₂ under UV irradiation.

进行了这项研究，以研究紫外线辐射对Pd催化的交叉偶联反应中催化活性的影响。通过先前报道的溶胶-凝胶法制备Pd-TiO ₂ -CNT复合材料，由此将锐钛矿型TiO ₂和金属Pd纳米颗粒沉积在碳纳米管（CNT）的表面上。这些纳米颗粒的平均粒径通过透射电子显微镜确定为〜4.3nm。制备的Pd-TiO ₂-CNT材料被用作用于Heck和脱羧偶联反应的催化剂，并且在不存在UV辐射的情况下，在存在UV辐射的情况下其显示出更高的催化活性。该体系增强的催化活性可以解释为Pd的亲核性增加，这是由于在紫外线照射下从TiO ₂转移电子所致。