Title: Zero-carbon energy and nanomaterials at scale: Solar-thermal synthesis of graphitic carbon and hydrogen via methane
decomposition

THURSDAY, MARCH, 10, 2022 11:00AM-11:50AM

Abstract: Current industrial processes for power, fuel, and commodity production are responsible for massive, ongoing CO
emissions that adversely affect the stability of Earth’s climate with potentially disastrous consequences. Increased use of hydrogen
as a fuel and chemical building block promises to reduce CO emissions in critical sectors, but modern hydrogen production
technologies also involve high greenhouse gas emissions. Specifically, steam methane reforming (SMR) typically relies on fossilfuel
combustion to derive heat and constitutes 95% of current hydrogen production which yields substantial CO emissions. The
entirety of the combustion heating would be avoided by utilizing a portion of the bountiful 75,000 terawatts of solar power reaching
Earth's surface. This talk considers a process in which concentrated radiation from a simulated solar source converts methane to
high-value graphitic carbon and hydrogen gas. Methane flows within a photo-thermal reactor through the pores of a thin substrate
irradiated by several thousand suns at the focal peak. The methane decomposes primarily into hydrogen while depositing highly
graphitic carbon that grows conformally over ligaments in the porous substrate. The direct heating of the porous substrate serves
to capture the solid carbon into a readily captured and useful form while maintaining active deposition site density with persistent
catalytic activity. Results indicate a strong temperature dependence with high decomposition with concentration factors and
temperatures above 1000 suns and 1300 K, respectively. Even with a large flow area through regions of lower concentration and
temperature, methane conversion and hydrogen yields of approx. 70% are achieved, and nearly 60% of the inlet carbon is
captured in graphitic form.