CH4–CO2 reforming over Ni-substituted barium hexaaluminate catalysts

Structure–Activity Relationships of Nickel–Hexaaluminates in Reforming Reactions Part I: Controlling Nickel Nanoparticle Growth and Phase Formation

“…Ba,Ni-hexaaluminates calcined at 1200 8C Ba,Ni-hexaaluminates calcined at 1200 8C exhibited Ba-rich b"-alumina-like structures with characteristic reflexes at 2q = 32.18, 33.48 and 35.78, different form reports of Gardner et al [18][19][20][21][22][23] in which less Ba was utilized in the synthesis of the hexaaluminate (Ba 0.75 Ni y Al 12Ày O 19Àd ) than in this study (BaNi y Al 12Ày O 19Àd ). The difference between the perfect cells of b-alumina and the Ba-rich b"-alumina has been discussed by Iyi [44] and is presented in Figure 10.…”

“…[15,17,22] A high dispersion of Ni within the hexaaluminate lattice enables high dispersion of active centers formed by Ni 0 even after reduction. [18,23] The high stability of the resulting Ni nanoparticles after reduction is mandatory for all applications to keep a constant and high activity in reactions such as catalytic partial oxidation and reforming and to minimize carbon deposition. Additionally, carbon selectivity is widely believed to depend on Ni nanoparticle size, with a prerequisite for larger particles to favor growth of carbon deposits such as carbon whiskers.…”

Tuning the composition of metastable Co Ni Mg100−−(OH)(OCH3) nanoplates for optimizing robust methane dry reforming catalyst

“…S5 in the Supporting Information. When the Co content is less than 30 (Fig. S7 in the Supporting Information), allowing us to perform selected area electron diffraction (SAED) of a typical platelet.…”

“…(1) Catalyst synthesis methods aiming at small Ni particles have been proposed via reduction of Ni 2+ -substituted metal oxides or NiO-based solid solutions. For instance, Spivey et al suggested using Ni-substituted hexaaluminates [30] or pyrochlore [4] as precursors to prepare Ni 0 catalysts for MDR. Fujimoto et al [24], Hu and Ruckenstein [26,31,32], and Xu et al [33] used Ni-MgO solid solution as a precursor to prepare robust Ni 0 catalysts via H 2 reduction.…”

Structure–Activity Relationships of Nickel–Hexaaluminates in Reforming Reactions Part II: Activity and Stability of Nanostructured Nickel–Hexaaluminate‐Based Catalysts in the Dry Reforming of Methane

“…Methane chemisorbs preferentially on metallic Ni whereas CO 2 is chemisorbed preferentially on the large mirror plane cations, as it has been suggested by Gardner et al. with Ba,Ni–hexaaluminates 25. Gardner and co‐workers have quantified the basic site density over the catalyst surface depending on Ba surface segregation.…”