Hierarchical 2D/3D nanosheet materials for the production of hydrogen from methane without the formation of CO2 and for water purification.

点击翻译按钮获取中文摘要

The anthropogenic release of carbon dioxide to the atmosphere is measurable and cannot be denied. CO2 is a waste product of society's industrialization brought about by the complete combustion of fossil fuels. After water, it is the compound that contains the lowest exergy (available work) from complete combustion. It represents the waste having the lowest value from combustion. It is difficult to separate from nitrogen, difficult to compress and transport to a disposal site and finally inject underground. There are increasing questions as to whether it will leak from reservoirs over a period of 10,000 years. We can do better by producing hydrogen and pure carbon from these fuels. The hydrogen could be burnt for energy and the carbon stored as a solid. The objective of this proposal is to develop new catalysts and processes that can harness part of the energy contained in methane and produce solid carbon. This will be done with a new class of 2D/3D nanomaterials to be produced in the applicant's lab. ******Many hierarchically porous materials have been developed over the past ten years. They have demonstrated improved performance over conventional materials due to their greater surface area and improved accessibility to catalytically active sites. Most of these advancements have been based on a class of anionic clays known as layered double hydroxides (LDH). LDHs have been prepared by several methods such as co-precipitation, ion exchange, calcination-rehydration, hydrothermal and electrochemical. However, LDHs prepared by these methods are usually stone-like or plate-like and have limited surface areas. They need to be improved for potential applications. We have successfully synthesized 2D/3D nanoplatelet materials that have pores in the shape of slits of 200 nm width. These slit-like pores biomimic the pores found in the human kidney. This shape offers considerable resistance to fouling by proteins and colloids.******Most recently we have reinforced the 2D/3D nanoplatelets developed in our laboratories, placed them in packed beds and studied the dispersion of dyes passing through these beds. The nanoparticles were found to pack in beds that have a 10-fold lower dispersion than all packing materials reported in the literature. These latest results confirm the advantages of the slit pore geometries and the isoporous nature of these new packing materials. ******The objective of this work will be to produce self-assembled structures from nanoplatelets and reinforce them for use in packed beds and membranes. These structures will have slit-like pore geometries. They will be tested in the catalytic decomposition of methane to form hydrogen and carbon. They will also be deposited as fine filters on ceramic and metal supports to treat wastewaters containing colloids and fine particulates in order to reduce membrane fouling. The results of this work will lead to a new form of carbon sequestering and produce high-performance membranes.**