The nature of Ni-O pairs for ethane activation on NiO(100) and NiO(110) surfaces

Abstract

We investigated the activation of ethane on NiO(100) and NiO(110) surfaces with O vacancy or Ni vacancy. Our work demonstrates the role of Ni-O pairs for ethane activation on NiO(100) and NiO(110) surfaces. Ni-O pairs serve as the active sites for ethane dissociation, which proceeds via a heterolytic mechanism with acid-base interaction. Ethane activation is strongly preferred on NiO(110) surface than that on NiO(100) surface. The existence of O vacancy or Ni vacancy on NiO(100) surfaces has positive influence on C–H bond cleavage. But on NiO(110) surface, the presence of O vacancy or Ni vacancy may suppress the dissociation of ethane. This behavior is due to the reactivity of different Ni-O pairs. Hydrogen chemisorption, C2H5 chemisorption and bond strength may serve as potential descriptors for the nature of active sites. Based on the results of present work, it can be inferred that the strong chemisorption of hydrogen and C2H5 combined with the weaker bond strength of Ni-O pair can facilitate C–H bond cleavage and lower the barrier of ethane dissociation. Thus, surface is highly active toward ethane activation.