(529d) Methane Decarbonization for Hydrogen and Sequestered Carbon Nanofiber Co-Product

Hydrogen is one of the most essential chemical building blocks to our energy infrastructure, with downstream applications in oil refining as well as production of ammonia, the key component in fertilizer. Today, nearly all hydrogen is commercially produced via steam methane reforming in combination with the water gas shift reaction. For every kilogram of hydrogen produced, there are roughly 9 kilograms of CO₂ released to the atmosphere.¹ With an estimated global hydrogen production rate of 75 million metric tons per year¹, over 675 million metric tons of carbon dioxide are emitted via this process. A profitable alternative to produce hydrogen while circumventing greenhouse gas (GHG) is needed. A Catalytic-Chemical Vapor Deposition (CCVD) process to produce hydrogen and carbon nanofibers (CNFs) from methane is a financially promising alternative to steam methane reforming.

Methane, the primary component of natural gas, requires substantial process conditions to overcome the strong C – H bonds. Particle Atomic Layer Deposition (ALD) enables the formation of highly dispersed metal nanocatalysts on a given support which reduce the energy required for methane conversion. Moreover, the highly dispersed catalyst, consisting of abundant metals such as iron or nickel, is essential as this process contains a “sacrificial catalyst”; the catalyst, support, and CNFs combine as to form a sequestered carbon value-added product. In partnership with both the Hubler group in the department of Civil and Environmental Engineering and the National Ready Mixed Concrete Association (NRMCA), we are investigating the CNF/catalyst product to reduce cracking and improve the durability of ultra-high purity concrete (UHPC). The sacrificial catalyst circumvents the energy intensive step of product/catalyst separation as well as avoids the challenge of rapid catalyst deactivation.

In this research, abundant transition metals are deposited onto a support via particle ALD. CNFs and hydrogen are then generated via CCVD with the particle ALD catalyst. CCVD and catalyst synthesis parameters are investigated to maximize carbon and hydrogen yield. A preliminary technoeconomic analysis is performed to assess the viability of this technology at scale.

¹Bartlett, J., & Krupnick, A. 2020. “Decarbonized Hydrogen in the US Power and Industrial Sectors: Identifying and Incentivizing Opportunities to Lower Emissions” (Report 20-25). Resources for the Future.