Comparative study of mineral with different structures supported Fe-Ni catalysts for steam reforming of toluene

Fig. 1. The schematic diagram for steam reforming of toluene over mineral supported Fe and Ni catalysts. [Display omitted] •Four minerals with different structures are applied to prepare the Fe-Ni based catalysts for SRT.•Fe3Ni8/De exhibits good catalytic activity and stability toward toluene conversion.•The specific macropore morphology of diatomite could enhance the reactivity of Fe3Ni8/De in SRT reactions.•The strong interaction between Fe-Ni alloy and diatomite and the abundant silicon hydroxyl groups improve the coke resistance. Four abundant minerals with different structures including diatomite (De), montmorillonite (Mt), halloysite (Hal), and sepiolite (Sep), were used as the supports to prepare Fe-Ni based catalysts. The catalytic performances of these catalysts for steam reforming of toluene (SRT) were tested in a fixed-bed reactor under different conditions. The effects of S/C molar ratio, long-term stability and catalytic deactivation and regeneration were explored under the optimal condition, and the kinetic parameters were also determined. The fresh and spent catalysts were characterized using XRD, FT-IR, H2-TPR, BET, SEM, TEM, Raman spectroscopy and TG analyzer. The results showed that Fe3Ni8/De displayed the best catalytic activity with the highest toluene conversion and gas yields compared to those of Fe3Ni8/Hal, Fe3Ni8/Mt, and Fe3Ni8/Sep. The increase of the reaction temperature and S/C molar ratio apparently favored the catalytic activity and stability of the catalysts for SRT. The best catalytic performance of Fe3Ni8/De for SRT was achieved at the reaction temperature of 700 °C under the S/C molar ratio of 1.0. The apparent activation energy and pre-exponential factor for Fe3Ni8/De were determined to be 53.76 kJ⋅mol−1 and 2.72 × 105 m3⋅kg−1⋅h−1. The characterization of the spent catalysts indicated the high dispersion of Fe-Ni alloy and relatively low coke deposition of Fe3Ni8/De.