A better future for fossil hydrocarbons and carbon nanomaterials*

Every year we extract over 4.2 GT of oil, 2.5 GT of natural gas, and 3.4 GT of coal to sustain our economy. That’s equivalent to 8.7 GT of carbon and 1.3 GT of Hydrogen. Almost all of these resources are burned to generate energy, causing over 30 GT of CO2 to enter the atmosphere which is unsustainable in view of climate change—the only significant exception is polymers, which fix 0.35 GT/yr of hydrocarbon resources (~3% of the total production) into valuable solid materials. At the same time, every year we use over 12% of the world energy production (over 60 EJ) towards primary metals; most of this energy goes into mining, refining, and processing ~3 GT/yr of metal ores into usable metals, chiefly 1.6 GT/yr of steel, 50 MT/yr of Aluminum, and 20 MT/yr of Copper; it is accompanied by the generation of 3.7 GT of CO2 emissions, equivalent to ~20% of the emissions caused by burning oil and gas. This is the extent of our “materials-energy nexus”.

Can we break this inefficient cycle and replace metals with materials made directly from hydrocarbons? Carbon Nanomaterials—primarily CNTs and graphene—offer an opportunity. They can be made via pyrolysis of methane and other hydrocarbons, with concurrent production of hydrogen. In the past decade, methods have been developed to convert CNTs and graphene into macroscopic materials (fibers, sheets, 3D structures) that could displace metals based on their properties—strength, electrical and thermal conductivity. In this talk, I will discuss why carbon nanomaterials could be great candidates to utilize natural gas on a very large scale (GT/yr) to make materials with zero CO2 footprint and positive hydrogen production. I will outline the scientific problems that need to be solved to realize highly-efficient synthesis and conversion of these materials and will present an estimate of the potential benefits of such a transition in our use of fossil hydrocarbons.