368 / 2018-07-24 17:05:23

Promoting hydrogen-rich syngas production from pyrolysis of biomass over hierarchically structured Ni-based catalysts

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Novel hierarchically structured Ni-based catalysts (Ni–Al and Ni–Zn) were successfully synthesized by a simple hydrothermal process, and applied for hydrogen-rich syngas production from biomass pyrolysis. Various characterization techniques such as XRD, SEM, BET and H2-TPR were employed to thoroughly characterize the fresh catalysts. The results reveal that the developed Ni-based catalysts are found to be highly effective for hydrogen-rich syngas production. High gasification efficiencies of 65.9 and 59.6 wt.%, syngas yields of 745 and 655 mL/g biomass, H2 yields of 316 and 305 mL/g biomass as well as H2/CO molar ratios of 2.28 and 3.05 were obtained for Ni–Al and Ni–Zn catalysts, respectively, at a moderate pyrolysis temperature of 700 oC. Based on the results of structure characteristics, this might be due to their unique hierarchical structure (three-dimensional flower-like and one-dimensional nanorods) with Ni species homogeneous dispersed on the surface, which can effectively reduce the coverage of active centre caused by disorder aggregation and improve the thermal stability. As a result, more active sites can be accessible for reactants to promote the cracking/reforming reactions of pyrolysis volatiles. The resulting syngas are favored for further Fischer–Tropsch synthesis reaction and other synthesis reactions for the production of liquid hydrocarbons.