Impact of nanoparticle exsolution on dry reforming of methane: Improving catalytic activity by reductive pre-treatment of perovskite-type catalysts

Nanoparticle Exsolution from Nanoporous Perovskites for Highly Active and Stable Catalysts

“…The fact though that n‐LSTNR500 surpasses n‐LSTNR900 in catalytic activity above this temperature can be attributed to a further Ni reduction under the CH 4 ‐rich reaction atmosphere, something that has also been observed and studied in detail in other works. [ 62–64 ] 1% Ni/Al 2 O 3 had a similar performance to n‐LSTNR900 above 550 °C, whereas in all catalysts the H 2 /CO ratio was close to 1 (Figure S10a, Supporting Information).…”

Exsolution on perovskite oxides: morphology and anchorage of nanoparticles

“…Exsolution as a process has been studied extensively. [13][14][15][16][17][18][19] Depending on the conditions, it reversibly 20 leads to the decoration of a material's surface with finely dispersed nanoparticles. 16 The formation of such nanoparticles can be achieved before reactions (in reducing gas atmospheres or electrically by applying a bias to the sample 21,22 ) or in situ, provided the reaction conditions are sufficiently reducing: 14,23 The perovskite material is partially reduced causing reducible B-site cations to migrate to the surface, where they exsolve and form metallic or oxidic nanoparticles (depending on the conditions) -as can be seen in Fig.…”

“…1,25 (c) Scope of this work Exsolution in perovskite oxides as well as its applications in catalysis and related fields have been the topic of extensive studies, since catalysts with nanoparticles formed via exsolution offer a great number of advantages and chances for new and improved catalysts. [13][14][15][16][17][18][19] However, to our knowledge more detailed investigations of the connection between exsolution conditions and morphology (size, population density, shape) and anchorage of the resulting nanoparticles are still rare. Especially so in the context of comparisons across different materials.…”

“…12 In our own work, we utilise iron-based perovskite oxides as catalysts for multiple reactions (e.g. reverse water-gas shift 13 or methane dry reforming 14 ) because of their highly beneficial properties: this type of perovskite oxides can be used at high temperatures, as they are thermally stable. Due to their compositional flexibility and their tunability (both A-and B-sites can be relatively easily doped with catalytically active elements), perovskite oxides lend themselves to a rational catalyst design approach.…”

“…Exsolution as a process has been studied extensively. 13–19 Depending on the conditions, it reversibly 20 leads to the decoration of a material's surface with finely dispersed nanoparticles. 16 The formation of such nanoparticles can be achieved before reactions (in reducing gas atmospheres or electrically by applying a bias to the sample 21,22 ) or in situ , provided the reaction conditions are sufficiently reducing: 14,23…”