Unsupported nickel catalyst prepared from nickel foam for methane decomposition and recycling the carbon deposited spent catalyst

Catalytic methane decomposition (CMD) receives increasing attention for co-production of COx-free hydrogen and valuable carbon by-product, and the catalyst plays a crucial role on methane conversion and the product features. Unsupported nickel catalysts derived from commercial nickel foam (NF) were prepared for CMD by mild pre-treatment. Effects of the pre-treatment method (acid treatment, thermal treatment, acid-thermal treatment and hydrogen reduction) and reaction temperature were explored on the NF morphology and CMD reactivity in a fixed-bed reactor. It is found that catalytic performance of the NF-based catalyst is highly dependent on the pre-treatment and reaction temperature. The thermal and acid-thermal treatments could greatly promote the catalytic activity (with methane conversion up to 74.6% and 91.8%, respectively) at 850 C-circle. To fully release potential abilities of the catalyst, the carbon deposited spent catalyst was recycled as a fresh catalyst in the CMD test by several strategies. High and stable methane conversion (up to around 90%-93%) can be achieved by simulating the operation model in a fluidized-bed reactor for a continuous CMD process. Besides, the carbon deposited spent catalyst could serve as a promising candidate of supercapacitor electrode material. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Catalytic methane decomposition using unsupported nickel catalysts derived from commercial nickel foam shows highly dependent catalytic performance on pre-treatment and reaction temperature. Thermal and acid-thermal treatments can greatly enhance catalytic activity, with methane conversion rates reaching up to 74.6% and 91.8% at 850 degrees Celsius. Recycling carbon deposited spent catalysts can achieve high and stable methane conversion rates, while the spent catalysts can also serve as promising candidates for supercapacitor electrode materials.