Influence of the Preparation Mode on Metal-Support Interactions in Pt/TiO2 Catalysts

Photonic efficiency and selectivity study of M (M=Pt, Pd, Au and Ag)/TiO2 photocatalysts for methanol reforming in the gas phase

“…The TEMs of the photocatalysts before and after use showed no obvious change, with the metal particle sizes remaining unchanged. Note that in a previous paper [23], using ostensibly the same Pt/TiO 2 photocatalyst, aggregated Pt particles of 2-3 nm were observed using HAADF STEM and this might appear to suggest some lack or reliability in the method of production, the incipient wetness method -which would be surprising given it widespread use [23,[26][27][28][29]. However, a closer inspection of the HAADF STEM image reveals that whilst some aggregated particles were present, the bulk of the Pt particles appeared to be ca.…”

“…The powder was subsequently reduced at 200 o C for 2 h in a tubular furnace under a steady flow of pure H 2 (50 cm 3 min -1 ), thereby yielding the 0.2 wt% Pt/TiO 2 photocatalyst. Note: the incipient wetness method, with its final reduction step, is often used by the catalyst community to produce nanoparticulate metal dispersions on a wide variety of inert substrates [23,[26][27][28][29]. In this work, as noted elsewhere, the conversion of the cream colour PtO 2 coated TiO 2 powder particles by the hydrogen produces a striking and rapid colour change to a grey powder, commonly assumed to be due to the reduction of the metal oxide to the metal, as illustrated by the before and after photographic images illustrated in the figure S2 in the SI section; no further colour change is effected by increasing the temperature of reduction reactor temperature even to 500 o C. Temperature programme reduction studies of the Pt/TiO 2 catalyst produced using this technique show that the reduction is readily effected at 200 o C [27,29].…”

Structural Characterization of Automotive Catalysts

“…PEGDE (Poly(ethylene glycol)-dimethylether) seems to be a valuable alternative. [81] Finally, the stabilization of the nanodispersed platinum particles is still unsolved, after short aging periods the particle sintering levels the originally prepared particle distribution. In spite of these actual disadvantages, which are a matter of current research, the microemulsion method seems promising for the preparation of supported automotive catalysts with sharply defined noble metal particles.…”

Preparation of catalysts from microemulsions and their applications in heterogeneous catalysis

“…The isomerisation and hydrogenolysis reactions of different hexanes have been thoroughly investigated for monodispersed colloidal platinum particles on alumina [18], titania [19] and for colloidal platinum/palladium alloy particles on alumina [20]. The possibility to prepare nanosized metal alloys of narrow size distribution at room temperature is a very attractive feature and is successfully demonstrated [20].…”