Intermetallic compounds in heterogeneous catalysis—a quickly developing field

Abstract

The application of intermetallic compounds for understanding in heterogeneous catalysis developed in an excellent way during the last decade. This review provides an overview of concepts and developments revealing the potential of intermetallic compounds in fundamental as well as applied catalysis research. Intermetallic compounds may be considered as platform materials to address current and future catalytic challenges, e.g. in respect to the energy transition.

Formation of GaPd2 and GaPd intermetallic compounds on GaN(0001)

“…Crystal structure of the compounds provides surfaces with all Pd atoms structurally ordered and isolated by Ga atoms, fulfilling the earlier proposed active site isolation concept [5,7]. The concept assumes formation of isolated catalytic centers, which consist of active atoms (Pd) isolated by less active spacer atoms (Ga) on the surface of the catalyst [5,7]. It limits the number of adsorption configurations for the reactants and changes the electronic structure of the active species according to the nature and concentration of the spacer atoms [7][8][9].…”

“…Therefore, an activation of di-hydrogen as a reactant can easily be achieved due to a sufficient density of states near the fermi level. Crystal structure of the compounds provides surfaces with all Pd atoms structurally ordered and isolated by Ga atoms, fulfilling the earlier proposed active site isolation concept [5,7]. The concept assumes formation of isolated catalytic centers, which consist of active atoms (Pd) isolated by less active spacer atoms (Ga) on the surface of the catalyst [5,7].…”

“…The GaPd, Ga Pd 2 and Ga 7 Pd 3 intermetallic compounds have been verified as highly active and stable, selective catalysts in the semi-hydrogenation of acetylene [1][2][3][4][5]. This industrially very important reaction is widely employed in polyethylene production to remove traces of acetylene from the ethylene stream [6].…”

“…It limits the number of adsorption configurations for the reactants and changes the electronic structure of the active species according to the nature and concentration of the spacer atoms [7][8][9]. The covalent bonding within the compounds leads to a much higher stability against surface segregation even under reaction conditions [5]. So far, well-defined and reproducibly obtainable unsupported Ga-Pd intermetallic compounds with a rather low specific surface area and ultrathin Ga films on Pd(111) and Pd(110) surfaces have been used for basic research on physicochemical and catalytic properties of these compounds [1][2][3][4][5]10].…”

Solid Particle Erosion of Aluminum In-Situ Reinforced with a Cobalt Aluminide

“…Despite the significant research interest in the intermetallic compounds of Al, only few studies have been devoted to cobalt aluminides, possibly due to their limited, until recently, application potential. Co-aluminides may find applications as active heterogeneous catalysts [2], metallization layers in III-V semiconductor devices [3], to hydrogen fuel cell technologies [4] etc. Recently, the development of a new category of materials, that of Complex Metallic Alloys (CMAs)-Quasi Crystals (QCs) [5] has rekindled the interest in the Al-Co system: CMAs constitute a new class of intermetallic compounds with high structural complexity, giant unit cells containing from tens to more than a thousand atoms and lattice parameters of several nanometers [6].…”