6.4.2018 14:30 - 6.4.2018 15:30
Ayazağa Kampüsü, Ayazağa Kampüsü
Akademik
Abstract:
Controlling the selectivity is one of the key challenges in heterogenous catalysis. Changing surface characteristics of the supports, varying metal nanoparticle size, incorporating promoters or adding a second or third metal offer opportunities in the way of tuning the electronic environment, which in turn helps to control the selectivity. Another approach in this regard is to coat the surface of a solid catalyst with an ionic liquid (IL) layer. In this talk, some of the recent results obtained in our research group by coating supported metal catalysts with ILs will be presented. First, an example on an ordinary commercial supported nickel catalyst will be illustrated. Detailed characterization complemented by density functional theory calculations showed that an IL coating layer directly interacts with the active nickel sites. Data indicated that this interaction occurs via electron donation from IL to the metal sites. This ligand effect of the IL coating influences the selectivity of nickel sites for partial hydrogenation. The catalytic performance tests on 1,3-butadiene hydrogenation illustrated that the selectivity toward total butenes becomes more than 97% throughout the whole conversion range upon coating the supported nickel catalysts with ILs. Aiming at investigating the structural factors controlling this ligand effect of ILs on supported metal catalysts, single-site metal catalysts were also coated with a family of ILs. High energy resolution fluorescence detection (HERFD) X-ray absorption near-edge spectroscopy (XANES) measurements illustrated a strong correlation between the degree of electron donation from IL coating layer to the metal sites and the interionic interaction energy in ILs. The performance testings on these catalysts showed that the catalyst becomes more selective for partial hydrogenation with an increase in the degree of electron donation from IL. These results present opportunities for tuning the performance of supported metal catalysts by tailoring the structure of the IL coating layer.