Growth and structure of supported metal catalyst particles

Understanding and Controlling the Aggregative Growth of Platinum Nanoparticles in Atomic Layer Deposition: An Avenue to Size Selection

“…48,49 However, for Ostwald ripening to take place, several kinetic steps have to be realized: atom detachment from small NPs, surface diffusion or transport through the vapor phase to larger NPs, and subsequent attachment. 27,50,51 Each of these steps can be kinetically limited due to large energy barriers. In the case of platinum, the high Pt–Pt bond energy makes the detachment of an atom from Pt NPs an unlikely event, 27,48,50,51 especially when Pt does not enjoy a very strong adsorption on the support.…”

Tomographic Heating Holder forIn SituTEM: Study of Pt/C and PtPd/Al2O3Catalysts as a Function of Temperature

“…(2) Ostwald ripening, involving the migration of individual atoms from the particles onto the support, across the support, and onto other particles (Simonsen et al, 2010). Ostwald ripening is strongly dependent on atomic diffusivity (Linderoth et al, 1997;Horch et al, 1999) and can also happen in faceted particles in the form of inhibited nucleation, which arises from nucleation constraints and leads to slower growth rates than predicted by classical ripening theories (Wynblatt, 1976;Wynblatt & Gjostein, 1976); (3) An extension of Ostwald ripening, involving interparticle transport via a volatile oxide species (Harris, 1995;Ahn et al, 1981).…”

Long-term stability of Pt/alumina catalyst combustors for micro-gas sensor application

“…The migration and coalescence of the particles cause the growth of Pt grain size and the loss of the active surface area, to lose its activity and stability. [1][2][3][4] The aging treatment is considered effective to prevent this degradation of catalyst performance. Before determining the aging temperature and period, we have heated the Fig.…”

“…However, because the sintering of Pt particles in the catalyst occurs in the Pt/alumina catalyst used at high temperature, it is expected that the activity of the catalyst decreases significantly with this degradation of Pt particle sintering. [1][2][3][4] Therefore, the development of the catalyst which has the better stability is important for the development of the robust gas sensor.…”