Influence of the tensile strain on CH4 dissociation on Cu(100) surface: A theoretical study

Abstract Tensile strain is widespread on the catalyst surface due to the lattice mismatch between the catalyst and substrate, such as Cu/MgO in this work. Thus, it is important to investigate the influence of tensile strain on the catalytic properties. In this study, we have investigated the CH 4 dissociation on Cu(1 0 0) surface by considering the tensile strain. Our results showed that compared with the unstrained Cu(1 0 0) surface, the most stable sites for dissociation species CH x ( x  = 0⿿3) and H adsorption on strained surface remain unchanged. The surface strain strengthens CH x ( x  = 0⿿3) adsorption, while weakens H adsorption. The elementary reaction for CH 4 dissociation with the largest electronic energy barrier changes from CH ⿿ C + H on the unstrained surface to CH 4  ⿿ CH 3  + H on the strained surface (for strain equal to and larger than 3%), in agreement with the experimental observation that CH 4 dissociation into CH 3 and H is the most difficult reaction. The tensile strain accelerates C migration while has no obvious influence for C polymerization. Both DFT calculations and microkinetic model demonstrated that the strain hinders the CH 4 dissociation process on Cu(1 0 0) surface. CH 4 dissociation rate depends sensitively on the magnitude of the surface tensile strain.