A catalyst for one-step isoparaffin production via fischer-tropsch synthesis: Growth of a H-mordenite shell encapsulating a fused iron core

Fused iron (FI), is a general Fischer-Tropsch synthesis (FTS) catalyst and can be used to convert syngas (CO+H₂) into normal hydrocarbons. The syntheses of HZSM-5 or H-β zeolite-shell encapsulated catalysts for FTS have been reported previously, however, conventional zeolite-shell synthesis generally employs an organic template, which is neither economic nor environmentally benign. Here we report the synthesis, without using an organic template, of a millimeter-sized defect-free capsule catalyst covered by a MOR zeolite shell (thickness of 23μm) on FI pellets. The capsule catalyst (HMOR/FI) exhibited excellent performance for FTS, greatly increasing the selectivity of middle isoparaffins. Compared with the pure FI catalyst, the CO conversion of the HMOR/FI capsule catalyst increased remarkably and the iso/n ratio was almost 8times that of the pure FI catalyst. This report provides an effective route to synthesize a capsule catalyst, which can reduce costs effectively and is also more environmentally benign than the current conventional zeolite-shell synthesis. Capsule catalyst: A H-mordenite (HMOR) zeolite shell is directly synthesized, without an organic template, on a silicalite-1 coated fused iron catalyst. When applied to Fischer-Tropsch synthesis (FTS), the selectivity of the prepared capsule catalyst to middle isoparaffins is significantly better than a physical mixture catalyst.