Fig. 1: Structural characterization and catalytic performance.

a–c TEM image (a), EDS elemental mapping (b), and structural model (c) of the spent Fe@Mn@0.2Si catalyst. d–f TEM image (d), EDS elemental mapping (e), and structural model (f) of the spent Fe@Mn@0.2Si-c catalyst. g Phase composition of the spent catalysts determined by Mössbauer spectroscopy. h, i CO conversion (h) and hydrocarbons distribution (i) of the Fe@Mn@0.2Si and Fe@Mn@0.2Si-c catalysts.