From the grafting of NHC-based Pd(II) complexes onto TiO2 to the in situ generation of Mott-Schottky heterojunctions: The boosting effect in the Suzuki-Miyaura reaction. Do the evolved Pd NPs act as reservoirs?
作者:Jonathan De Tovar、Franck Rataboul、Laurent Djakovitch
DOI:10.1016/j.jcat.2021.04.016
日期:2021.6
synthesized for immobilization at the surface of TiO2. The studies reveal that once the complexes are anchored onto TiO2, the mechanism governing the catalytic reaction is different from that observed for the non-anchored complexes. All complexes evolved to Pd NPs at the surface of TiO2 under reaction conditions and released Pd species in the liquid phase. Also, this reactivity was boosted by the in situ generation
经常提出这样一个假设,即涉及铃木-宫浦反应的真实活性物种是均质的,异质的或两者兼而有之。但是,由于缺乏对真正催化实体及其监控的表征,因此这些假设有些难以捉摸。在这里,为了获得对铃木-宫浦反应中活性物种形成的新见解,合成了带有双(NHC)配体的钯(II)配合物家族,用于固定在TiO 2的表面上。研究表明,一旦将络合物固定在TiO 2上,控制催化反应的机理就与非锚定络合物所观察到的机理不同。所有络合物在TiO 2表面演化为Pd NPs在反应条件下会在液相中释放出Pd物质。同样,通过原位产生莫特-肖特基异质结提高了这种反应性,为设计异质催化剂以进一步在逆流反应器中实施开辟了新的途径。