Nonthermalized Precursor-Mediated Dissociative Chemisorption at High Catalysis Temperatures.

Quasiclassical trajectory calculations and vibrational-state-selected beam-surface measurements of CH chemisorption on Ir(111) reveal a nonthermal, hot-molecule mechanism for C-H bond activation. Low-energy vibrationally excited molecules become trapped in the physisorption well and react before vibrational and translational energies accommodate the surface. The reaction probability is strongly surface-temperature-dependent and arises from the pivotal role of Ir atom thermal motion.

Gold decoration of silica by decomposition of aqueous gold(iii) hydroxide at low temperatures.

The decomposition of gold hydroxide to give metallic gold is known to take place around 300 °C in dry environments. However, little information about the gold hydroxide stability in wet environments has been recorded. Here, we present experimental evidence which shows that aqueous/water-enriched gold(iii) hydroxide colloids decompose spontaneously to form gold nanoparticles at temperature values above the freezing point of water.

One-step/one-pot decoration of oxide microparticles with silver nanoparticles.

Hypothesis: Heterogeneous nucleation of silver oxide (Ag2O) onto oxide microparticles (OMPs) followed by spontaneous thermal decomposition produce nanostructures made of OMPs decorated with silver nanoparticles (OMP|AgNPs).

Experiments: Colloidal chemistry methods have been used to produce the decoration of OMPs with silver nanoparticles (AgNPs), by carrying out the Ag2O precipitation/thermal decomposition. The process is driven in water enriched acetone medium containing NaOH, NH3, AgNO3 and SiO2MPs as substrate.