Properties of Bulk In‐Pt Intermetallic Compounds in Methanol Steam Reforming

Abstract

Heterogeneous catalysts are often complex materials containing different compounds. While this can lead to highly beneficial interfaces, it is difficult to identify the role of single components. In methanol steam reforming (MSR), the interplay between intermetallic compounds, supporting oxides and redox reactions leads to highly active and CO 2 -selective materials. Herein, the intrinsic catalytic properties of unsupported In 3 Pt 2 , In 2 Pt, and In 7 Pt 3 as model systems for Pt/In 2 O 3 -based catalytic materials in MSR are addressed. In 2 Pt was identified as the essential compound responsible for the reported excellent CO 2selectivity of 99.5 % at 300 °C in supported systems, showing a CO 2 -selectivity above 99 % even at 400 °C. Additionally, the partial oxidation of In 7 Pt 3 revealed that too much In 2 O 3 is detrimental for the catalytic properties. The study highlights the crucial role of intermetallic InÀ Pt compounds in Pt/In 2 O 3 materials with excellent CO 2 -selectivity.

Fundamental understanding of the synthesis of well-defined supported non-noble metal intermetallic compound nanoparticles

“…Traditional methods for production of an ingot of material are through arc melting and high-frequency heating methods at high temperature, followed by ball-milling to produce particles with particle size on a scale of micrometers. [66][67][68][69][70][71][72][73][74][75][76][77] Despite the ingot method providing phase-pure materials initially, the method offers little control of morphology, particle size, and particle surface composition when producing particles from the ingot through grinding or ball milling. [66][67][68] In addition, the particles can be contaminated and oxidized during the milling process due to the use of a solvent.…”

Surface Redox Dynamics in Gold–Zinc CO2 Hydrogenation Catalysts

“…Notably, the extent of dealloying for these systems correlates with selectivity for methanol (i.e., Au–Zn < Pd–Ga < Cu–Zn ≈ Cu–Ga), indicating that (de)­alloying may be a useful descriptor for selectivity in CO 2 hydrogenation (SI S6). Moreover, this is consistent with what has been observed for the reverse reaction, methanol steam-reforming, where the presence of oxide species is critical for high activity and selectivity. , …”

“…11 Moreover, this is consistent with what has been observed for the reverse reaction, methanol steam-reforming, where the presence of oxide species is critical for high activity and selectivity. 37,38 In summary, by exploiting a tailored silica-supported Au−Zn catalyst and in situ XAS, we have been able to explicitly study the complex chemistry occurring at the surface of Au−Zn@ SiO 2 during CO 2 hydrogenation. In situ XAS shows that H 2 pretreatment promotes formation of an Au−Zn alloy, reconciling earlier observations regarding Au−Zn catalysts, highlighting the importance of the Au−Zn alloy for reactivity.…”