Morphology-Dependent Catalytic Activity of ZnFe2O4 Spinel Toward Light Olefins from Fischer–Tropsch Synthesis

Graphical ZnFe 2 O 4 spinel with various morphologies for FTS : Compared to octahedral ZnFe 2 O 4 spinel, the cubic ZnFe 2 O 4 spinel was more prone to the formation of Fe 5 C 2 phase under syngas atmosphere and exhibited higher catalytic activity and light olefins selectivity. The shape-defined ZnFe 2 O 4 spinel with cubic and octahedral morphology was hydrothermally synthesized, respectively, and used as catalyst precursor for Fischer–Tropsch synthesis (FTS). The structure of ZnFe 2 O 4 spinel was changed to ZnO and Fe 5 C 2 (Fe 5 C 2 /ZnO) after reduction and carbonization. Interestingly, ZnFe 2 O 4 with cubic morphology exhibited much higher catalytic activity and selectivity toward low-carbon olefins (C 2 –C 4 ) than the octahedral one under identical conditions, and the latter tended to produce the saturated alkanes. The primary properties of ZnFe 2 O 4 materials before and after reduction were systematically studied through a series of characteristic technologies to reveal the difference in catalytic performance between the two ZnFe 2 O 4 spinels with different morphologies.