Fig. 3: Growth time of inhomogeneous MOF layers controlling the number of mesoporous shells.

TEM images of MOF precursor particles with (a) single, (e) double, (i) quadruple, and (m) quintuple inhomogeneous layers. TEM images of the corresponding products after etching treatment and schematic models: b–d 1S-mesoUiO-66-NH2, f–h 2S-mesoUiO-66-NH2, j–l 4S-mesoUiO-66-NH2, and n–p 5S-mesoUiO-66-NH2 HoMSs.