Low temperature methane conversion with perovskite-supported exo/endo-particles

Abstract

Lowering methane conversion temperature has been long-sought in energy conversion applications and is now being realised via exo/endo-particle perovskites.

A-site deficient chromite with in situ Ni exsolution as a fuel electrode for solid oxide cells (SOCs)

“…48 This would be consistent with the above-mentioned observations made on the nickel concentration determined by XPS on the surface of the as-prepared and reduced L65SCrN samples. Such high surface diffusivity was highlighted by Sakai et al, who investigated the chromium diffusion in lanthanum chromites between $700-1400 C by 50 Cr tracer diffusion and secondary ion mass spectrometry (SIMS). 49 They estimated that independently of the temperature, the grain boundary diffusion coefficient was 10 5 times larger than the bulk diffusion coefficient.…”

“…These conjectures were made based on a SEM cross-section evaluation, where it is possible to identify the surface and the bulk. 50 Moreover, it is possible to correlate the differences in the observed Ni exsolution morphologies at 500 C and 900 C upon reduction (Fig. 6) with the formation of oxygen vacancies, since the exsolution is favored when these vacancies reach a high concentration.…”

Trends and Prospects of Bimetallic Exsolution

“…The particles seem to have Ni segregated at the core while Co was more homogenously dispersed throughout the nanoparticles. The system demonstrated high oxygen capacity, high stability over redox cycling and resistance to deactivation mechanisms like sintering and coking while still exhibiting good surface activity, all significant properties for redox cycling applications [8d] …”

Boosting methane partial oxidation on ceria through exsolution of robust Ru nanoparticles

“…Despite the increased value exRuCeO 2 respect to CeO 2 , the oxygen supply capacity is still below the values reported for perovskites, for instance c.a. 0.4 mol O mol oxide -1 for La 0.8 Ce 0.1 Ni 0.4 Ti 0.6 O A L 30. .…”