Carbon is not only a major product of the methane decomposition but also a catalyst for the heterogeneous methane decomposition reaction. It is highly desirable that the morphology and surface properties of the product carbon be controlled to maximize their catalytic effects. In this paper, we characterize the physical properties of two activated carbon samples by sizes, and crystallographic structures using scanning electron microscope, x-ray diffraction, particle size analyzer, and surface area measurement. The paper also includes high temperature thermogravimetric experiment results on the carbon–hydrogen reaction to show if the injected carbon particles reacts with the formed hydrogen, which has not been studied in solar thermal hydrocarbon decomposition before. Results show that carbon does not react with hydrogen to form methane or any other intermediate compounds up until 900°C, which explains the favorable effect of carbon laden flow experiments for catalytic methane decomposition at lower temperatures. These results will be used to identify the optimal operating conditions for our solar reactor.

The purpose of this research is to develop a process to use plasma decomposition of hydrocarbon liquids or clathrate hydrates in a microwave oven to produce fuel gas while simultaneously solidifying the carbon and synthesizing it into useful carbonized materials, such as CNTs or activated charcoal. Hydrogen gas with a purity of 60% to 80% can be extracted using a conventional microwave oven. This means that the energy efficiency of hydrogen production using this method is estimated to be approximately 50% of that by electrolysis of alkaline water and approximately 1% of that by the natural gas steam reforming method. However, this process has the added benefit of producing solid carbon at the same time. This method can be applied to a wide variety of waste liquids, or hydrate. Surplus electrical energy could be used to process waste liquids from homes and factories, and the resulting hydrogen energy could be stored and used.