Low-temperature catalytic methane splitting: A new reactor design for long-term hydrogen production

Abstract

The low-temperature catalytic methane splitting, also known as methane decomposition, is expected to play a critical role in hydrogen production since it can use methane as in steam reforming but without carbon emissions. However, the production of solid carbon hinders the long-term stability of the catalytic process and its adoption as an industrially feasible technology. Until now, reactor designs such as fixed or fluidized beds did not overcome clogging and fast catalyst deactivation caused by carbon formation below 900 degrees C. In this work, different reactor designs were tested to study their performance in terms of catalytic activity and stability. The use of thin and porous layers of a commercial Ni/SiO2-Al2O3 catalyst extended the catalytic stability from 1.8 h (using a fixed bed reactor) to 46.4 h (using a tubular coated reactor); corresponding to a production increase from 0.3 gC center dot gcat 1 to 62 gC center dot gcat 1, respectively. Carbon clogging and pressure build-up were avoided using a coated reactor containing catalytic substrates prepared by screen-printing and dip-coating techniques. The produced solid carbon was mainly filamentous. Therefore, the designed coated reactors displayed better stability and, if combined with interfacial cyclic carbon hydrogenation strategies to regenerate the catalyst, they are expected to be fully stable. The work provides a pathway for scaling up low-temperature catalytic methane splitting for largescale deployment of dispatchable low-cost hydrogen production.