Zirconia-supported bimetallic RhPt catalysts: Characterization and testing in autothermal reforming of simulated gasoline

Hydrogen Production by Steam Reforming of Ethanol on Rh-Pt Catalysts: Influence of CeO2, ZrO2, and La2O3 as Supports

“…Only Pt 0 (71.7 eV) was detected in reduced and aged RhPt/ZrO2. The stability of reduced Pt was previously reported for a Pt/ZrO2 catalyst [61,67]. This metal accommodation over the support seems to affect H2 selectivity, as observed in Figure 1b.…”

“…As reported by Kaila et al [61], the presence of an alloy on these bimetallic catalysts is possible with all Rh/Pt ratios because of the miscibility of the RhxPt1−x system. The RhxPt1−x alloys result in a strong Pt enrichment of the surface as the temperature increases [35,47] which agrees with our results on the aged RhPt/CeO2 catalyst, where Rh was not observed on the surface by XPS and diminished its surface concentration in EDX (Section 2.4.2).…”

“…According to this, the reduction of the catalysts at 700 °C before reaction appears to favor the availability of Pt on the catalyst surface, mitigating its adsorption into the support. However, Rh/(Rh + Pt) ratio approached to expected in RhPt/CeO2 and RhPt/ZrO2 after reaction, showing a possible adsorption of Pt into either the particles or the support [60,61]. In contrast, no significant changes in Rh/(Rh + Pt) ratio of reduced and aged RhPt/La2O3 samples were observed, but the total content of the metals on the surface decreased.…”

“…Both species play an important role in the catalytic process. Ce +4 acts as a Lewis acid by interacting with the O (2p) orbital of alcohols to form hydroxyl species that are intermediates in ethanol decomposition [60,61]. The presence of Ce +3 indicates the reduction of the CeO2 surface by interactions between a noble metal and Ce [67].…”

“…% Rh and 0.2 wt. % Pt were selected, based in previous investigations in which this ratio was found to be the more active for reforming reactions [30,61]. Low amounts of active metals (0.8 wt.…”