Fig. 4: Shape and morphology evolution of CuMgAl-MMO-HS particles.

Photos of CuMgAl-LDH precursors and derived MMOs in different states: a LDH precursor powders, b freshly calcined particles, c decomposed particles (active phase: Cu2O), d reduced particles (active phase: Cu) reduction under 2 vol% CO balanced with N2, e particles after regeneration (active phase: CuO) after 100 cycles in the FBR. f, g SEM image of the freshly calcined particles and h their surface, and i STEM image. j–l,SEM image of the particles at different magnifications, sample recovered after 100 cycles in the FBR, and m STEM image of cycled materials.