Extended Brewer hypo-hyper-d-interionic bonding theory II. Strong metal-support interaction grafting of composite electrocatalysts

摘要

The extended Brewer interactive interionic bonding theory (EBIIBT) to show the equivalence of interatomic and interionic bonding features, as the prerequisite for selective strong metal-support interactive (SMSI) grafting of metallic nanostructured catalyst upon active center of individual and composite hypo-d-electronic oxide supports was presented in the preceding part of the same study (Int. J. Hydrogen Energy). SMSI of both individual and composite, prevailingly hyper-d-electronic metallic electrocatalysts upon individual and/or composite, usually hypo-d-electronic oxide substrates, has been employed to create and graft (anchor) bifunctional electrocatalysts for simultaneous anodic hydrogen and CO oxidation in low temperature PEM (polymer exchange membrane) fuel cells (LT PEM FC), or at least for advanced CO tolerance. The selective interionic bonding method upon predestined active centers of hypo-d-electronic oxide supports has been adapted to graft (anchor) directly a priori defined nanosized intermetallic phases and synergetic bifunctional electrocatalysts from decomposition of corresponding stoichiometric mixtures of various individual or intermetallic acetylacetonates (2, 4-pentanedionates). An adapted TG method based on TPR has been properly used to test, define, control and stimulate the homogeneity of the intermetallic crystal cluster bonding and growth of nanostructured composite catalysts, mostly composed of rather extra stable Brewer type Laves fcc phases, formerly being grafted as interactive composite mixtures of 2,4-pentanedionate nanosized precursors upon proper SMSI hypo-d-interelectronic oxide supports. Their resulting bifunctional electrocatalytic properties are displayed and discussed. Thus, it has been pointed out that the term SMSI has primarily a broader hypo-hyper-d-interelectronic interactive sense in both the bonding effectiveness and bifunctional catalytic meaning, and in fact stays in the core of such extended Brewer interionic bonding theory.