Structural Changes in Nanoparticle Catalysts as Monitored by Their Magnetic Properties

Oxidation and thermal stability of nickel deposited on a thin alumina support

“…7). Now, in the absence of oxygen in the gas phase, annealing to similar temperatures leads to complete reduction of the Ni particles initially oxidized at 293 K. This result is consistent with investigations of Co particles on Al 2 O 3 / NiAl(1 1 0) where particles oxidized at 300 K could be reduced at temperatures around 530 K afterwards [42].…”

Controllable sealing of leaky alumina films on NiAl(100) surface by catalytic oxidation

“…At the presence of Co, another way to enhance oxidation is by catalytic oxidation, in which oxygen adsorbed on Co undergoes redox reaction with substrate Al [17][18][19][20] to form oxide. For the "catalytically grown oxide," we always start with a clean sample, form the striped oxide first, deposit Co, and then do the catalytic oxidation.…”

Towards an atomic level understanding of niobia based catalysts and catalysis by combining the science of catalysis with surface science

“…There is a strong propensity to form lower coordinated metal atoms on the nanoparticle at low temperature, as may be identified by IRAS studies . Co particles loose those low coordinated sites and sinter upon temperature increase as revealed by STM (Carlsson et al 2003c), ferromagnetic resonance (FMR (Hill et al 2005, Risse et al 2004), and IRAS measurements (Carlsson et al 2003c). The latter technique delivers detailed insight not only into sintering but also into the rearrangement at the surfaces of the particles, including the metal oxide interface.…”

“…The latter technique delivers detailed insight not only into sintering but also into the rearrangement at the surfaces of the particles, including the metal oxide interface. This is due to energetically separated surface resonances in FMR spectroscopy, which allows for separate investigation by gas adsorption at the metal vacuum and by temperature changes on the metal oxide interface (Risse et al 2004). Pd binds less strongly to the alumina surface and forms relatively large metallic particles at room temperature.…”

“…venture and try to address some of the fundamental questions that one encounters on such a journey (Carlsson et al 2003a, b, c, Freund et al 2003, Heemeier et al 2002, Hill et al 2005, Höbel et al 2006, Mendes et al 2006a, b, Nowitzki et al 2007, Risse et al 2004, Starr et al 2005, Uhl et al 2007). …”