Thermodynamics of the [Rh–In] system

Methanol Synthesis at a Wide Range of H2/CO2 Ratios over a Rh‐In Bimetallic Catalyst

“…HR-TEM images in Figure 2a and the Supporting Information, Figure S4a reveal that small islands of the two most stable crystalline intermediate phases of the Rh-In system (cubic-RhIn and tetragonal-RhIn 3 )atthe material interfaces were observed. [29] TEM of the co-RhIn/(5In5Al)O catalyst retrieved at the end of the long TOSt est also shows that both cubic-RhIn and tetragonal-RhIn 3 clusters embedded with the variable RhIn x composition at the metal-support interfaces with no observable particle sintering in the post-reaction catalyst (Supporting Information, Figure S4b), suggesting that Rh-In alloys are robust to maintain throughout the CO 2 hydrogenation mixture.Onthe other hand, the main light-contrast particles in the vicinity of darker Rh-In alloy clusters in the TEM images are confirmed to be hexagonal In 2 O 3 (Supporting Information, Figure S4 a,b). This observation is in agreement with the XRD patterns (Supporting Information, Figure S4c) that the hexagonal In 2 O 3 phase is the predominant structure in the co-RhIn/(5In5Al)O sample either before or after catalytic CO 2 hydrogenation testing.W ec annot detect any Rh-containing phases from XRD patterns owing to either the low Rh metal loading (ca.…”

“…Besides,t he alteration of the electronic property of Rh also signifies that charge transfer can occur from In to Rh when forming Rh-In alloy, which is in agreement with the thermodynamic observation reported previously. [29] In contrast, In 3d XPS spectra (Figure 3b)ofthe reduced samples show no distinguishable shift upon In incorporating into Rh catalysts owing to the fact that most In species stay as oxidic and only limited In 2 O 3 reduction could prompt the decoration of In on Rh, as confirmed by XRD (Supporting Information, Figure S4c) and In L 3 -edge XANES (Supporting Information, Figure S6b) showing that In mainly retains as the In 2 O 3 phase no matter before or after CO 2 hydrogenation reaction.…”

Intermetallic Nanocatalyst for Highly Active Heterogeneous Hydroformylation

“…While a tremendous amount of work has been done to study the formation process and properties of iNPs, Rh-based intermetallic phases received much less attention compared to Pt- or Pd-based intermetallic phases. The formation temperatures of intermetallic phases, usually well-described in the binary phase diagrams, are insufficiently documented or missing for many Rh-based systems (e.g., Rh–Ga, Rh–In, Rh–Zn). , While this can be associated with the high cost of Rh and its less common usage than Pt- or Pd-based catalysts, fundamental studies on Rh catalysts are undoubtedly necessary for applying them to specific chemical processes such as hydroformylation.…”

“…The formation temperatures of intermetallic phases, usually well-described in the binary phase diagrams, are insufficiently documented or missing for many Rh-based systems (e.g., Rh−Ga, Rh−In, Rh−Zn). 28,29 While this can be associated with the high cost of Rh and its less common usage than Pt-or Pd-based catalysts, fundamental studies on Rh catalysts are undoubtedly necessary for applying them to specific chemical processes such as hydroformylation.…”

Structure of catalytically active Rh–In bimetallic phase for amination of alcohols

“…[20][21][22][23][24] Even for bulk material, the structure or use of Rh-In alloy system has not been so intensively studied. 25,26 The known phases of Rh-In alloy are RhIn with cubic CsCl structure (a ¼ 0.320 nm) and RhIn 3 with tetragonal CoGa 3 structure (a ¼ 0.701 nm, c ¼ 0.715 nm). 27 The existence of Rh-rich Rh-In phase has been suggested; however not identied.…”