Bond activation and formation on inorganic surfaces

Abstract

The activation and formation of bonds on inorganic surfaces are important elementary processes in heterogeneous catalysis. The purpose of this chapter is to provide one way to clarify these processes in terms of the electronic structure of solid surfaces. In particular, the reader will learn how to rationalize the origin of the activation energy for bond breaking and formation on surfaces, focusing on the orbital interactions between the surface and the bond. There are very useful theoretical chemistry tools such as crystal orbital overlap population and crystal orbital Hamilton population that can be used to effectively retrieve information on bonds that are obscured in a bunch of surface bands. Local information on bonding on the surface is obtained. Information on the occupancy of electrons in the bonding and antibonding orbitals of the bond will prove to be very useful. Using such tools, one prescription is offered for the question of how to understand why the activation energy of bond breaking and formation on inorganic surfaces is high or low. What is covered in this chapter begins with simple metal surfaces and ends with more complex oxide and hydride surfaces. The interaction of various inorganic surfaces with bonds will be overviewed using examples from important topics in catalytic chemistry such as CO activation, Fischer-Tropsch synthesis, methane activation, and ammonia synthesis.