Controlling chemoselectivity of heterogeneous Pt catalysts via a support induced effect.

Tuning the chemoselectivity of a supported metal heterogeneous catalyst during hydrogenation reactions is extremely important and challenging, often achieved by changing the metal or adding homogeneous additives to the reaction. Tuning of the chemoselectivity for a given reaction over a supported metal catalyst, with a better understanding of the nature of the active site, is highly valuable to both academia and industry. Here, we report a support induced chemoselectivity (SIC) switch between Pt/TiO₂ and Pt/Nb₂O₅ during the hydrogenation of 3-nitrostyrene with high chemoselectivity. Specifically, 0.2%Pt/TiO₂ selectively reduces the -NO₂ group to form 3-vinyl aniline, whereas 0.2%Pt/Nb₂O₅ selectively reduces the C[double bond, length as m-dash]C bond to form 3-ethylnitrobenzene. Advanced characterisation and ab initio calculations indicate that the observed differences in selectivity could be because of support-dependent interactions at Pt-support interfacial sites, which modify the local electronic environment and adsorption behaviour of the substrate. These results suggest that the support-metal interfacial sites could potentially play a key role in controlling and switching chemoselectivity during 3-nitrostyrene hydrogenation. These results demonstrate that, in addition to modifying the metallic sites, the chemoselectivity of supported Pt nanoparticles can also be tuned by changing the support, offering an additional approach for designing new chemoselective supported metal catalysts for 3-nitrostyrene hydrogenation.