Weak Interactions Initiate C-H and C-C Bond Dissociation of Ethane on Nb n + Clusters.

The conversion of ethane into value-added chemicals under ambient conditions has attracted much attention but the mechanisms remain not fully understood. Here we report a study on the reaction of ethane with thermalized Nb n + clusters based on a multiple-ion laminar flow tube reactor combined with a triple quadrupole mass spectrometer (MIFT-TQMS). It is found that ethane reacts with Nb n + clusters to form both products of dehydrogenation and methane-removal (odd-carbon products). Combined with density functional theory (DFT) calculations, we studied the reaction mechanisms of the C-C bond activation and C-H bond cleavage on the Nb n + clusters. It is unveiled that hydrogen atom transfer (HAT) initiates the reaction process, giving rise to the formation of Nb-C bonds and an elongated C-C distance in the HNb n + CH 2 CH 3 motif. Subsequent reactions allow for C-C bond activation and a competitive HAT process which is associated with CH 4 removal or H 2 release, resulting in the production of the observed carbides.