Flame spray pyrolysis synthesized Ni-doped Fe/Ce oxygen carriers for chemical looping dry reforming of methane

The current study investigates a nano-Fe/Ce oxygen carriers (OCs) doped with Ni synthesized by flame spray pyrolysis (FSP) method for the chemical looping dry reforming of methane (CL-DRM). The thermodynamic analysis and reaction simulation of the CL-DRM process with iron-based oxygen carriers are first carried out. The result shows that when reacting with CH 4 , Fe 2 O 3 is reduced to Fe 3 O 4 at first, accompanied by generation of H 2 O and CO 2 , and then to Fe with H 2 and CO production. Fe can be oxidized to Fe 3 O 4 and FeO by CO 2 . Subsequently, based on the reaction patterns obtained from the aforementioned analysis, CL-DRM experiment using Ni-doped Fe/Ce oxygen carriers is conducted in a fixed-bed reactor, and the effects of different Ni doping and reaction conditions on the performance of the oxygen carriers are investigated. The OC with a Ni/Fe molar ratio of 2/98 (2NiFe) achieves over 30% CH 4 conversion and 90% CO selectivity in the partial oxidation step and stable cyclic performance. The FSP process facilitates high dispersion of Ni and formation of NiCe and NiFe alloys, which are stable active sites. Moreover, the transformation of Fe oxides and CeO 2 into CeFeO 3 on the surface of the OC has enhanced lattice oxygen availability and further improved cyclic stability.