Development of high-performance nickel-based catalysts for production of hydrogen and carbon nanotubes from biogas

Abstract

Selecting a suitable catalyst for implementing both simultaneous productions of hydrogen-rich syngas and multi-walled carbon nanotubes (MWCNTs) through the integration of dry reforming and methane decomposition reactions has recently gained great interests. In this study, a series of bimetallic (NiMo/MgO) and trimetallic (CoNiMo/MgO, FeNiMo/MgO, CoFeMo/MgO) catalysts was prepared and evaluated for a catalytic activity of CH4 and CO2 conversions of biogas in a fixed bed reactor at 800°C and atmospheric pressure. Among the catalysts investigated for directly converting biogas process, the bimetallic NiMo/MgO catalyst showed the outstanding catalytic performance with 86.4% CH4 conversion and 95.6% CO2 conversion as well as producing the highest syngas purity of 90.0% with H2/CO ratio = 1.1. Moreover, the characterization of the synthesized CNTs proved that the well-aligned structured morphology, high purity, and excellent textural properties were obtained using NiMo/MgO catalyst. On the other hand, using trimetallic catalysts which have the composition of Co and Fe particles leads to severe deactivation. This could be elucidated by the influence of the catalyst oxidation with CO2 in biogas, resulting in the transformation of metal into large metal oxide. The integrative process through using NiMo/MgO catalysts is regarded as a promising pathway, which has potentially useful for directly converting biogas into a high value-added product and provides a management approach for the enormous amounts of wastes.

Comparative Investigation of Yield and Quality of Carbon Nanotubes by Catalytic Conversion of Recycled Polypropylene and Polyethylene Plastics over Fe-Co-Mo/CaCO₃ Based on Chemical Vapour Deposition

“…The purity and quality of CNTs achieved from PP and PE over the catalysts Fe-Co-Mo/CaCO 3 were evaluated by thermal gravimetric analysis (TGA). The weight loss was attributed to the deposited carbon burnt in the air environment, which describes the yield of solid carbon on the catalysts [39]. Figures 8 (a) and (b) showed the percentage weight loss of CNTs produced from waste PP and PE, signifying that the samples have high carbon content, which described high purity CNTs corresponding to 94.71% and 94.40%.…”