Dissociation of Methane on Ni4 Cluster-A DFT Study

Publication date: Available online 1 March 2017 Source:Computational and Theoretical Chemistry Author(s): Ghanashyam Roy, Asoke Prasun Chattopadhyay The sequential four step dissociation of methane on Ni4 cluster has been investigated using density functional theory. The adsorption of CH4, CHx, C and H are exothermic and Gibbs free energy changes are negative on bare cluster. The dissociation of methane on Ni4 cluster is endothermic and thermodynamically not favorable at standard condition (T=298K, P=1atm). The dissociation of CHx(x=1-3) species on bare cluster show higher activation energy barrier than on the hydrogen preadsorbed cluster. The elementary step, CH→C, shows the highest activation energy barrier. Hence CH is the most stable intermediate. The Gibbs free energy changes are negative above 450K for CH4→CH3, CH3→CH2 and CH2→CH, whereas for CH→C above 550K at 1atm. Coke formation is possible above 550K. Graphical abstract

Source: Computational and Theoretical Chemistry - March 1, 2017 Category: Chemistry Source Type: research