Literature review of the catalytic pyrolysis of methane for hydrogen and carbon production

This review highlights recent developments and future perspectives in COx-free hydrogen production through methane pyrolysis. We give detailed discussions on thermal and catalytic methane cracking into hydrogen and carbon. Various types of solid and liquid catalysts were reviewed in terms of hydrogen selectivity, methane conversion, and deactivation. Some pilot scale technology was discussed; however, large-scale industrialisation is impeded by rapid solid catalyst deactivation, low-priced carbon (by-product) of molten catalysts, harsh conditions for reactor materials, and performance of stable molten catalysts. For catalytic methane cracking in molten catalysts (salt or metal), substantial advances in catalyst development, product separation, and reactor design are still required to commercialise methane pyrolysis for hydrogen production. To provide guidance to future works in this area, the review is specifically focused on (i) design of catalysts (ii) recent developments of molten salt-based methane cracking, (iii) reactor design and process design.& COPY; 2023 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This review summarizes recent developments and future perspectives in COx-free hydrogen production through methane pyrolysis. It discusses in detail the thermal and catalytic cracking of methane into hydrogen and carbon. Various types of solid and liquid catalysts are reviewed in terms of their performance in hydrogen selectivity, methane conversion, and deactivation. Although some pilot-scale technologies have been discussed, large-scale industrialization is hindered by challenges such as rapid solid catalyst deactivation, low-priced carbon by-product of molten catalysts, harsh reactor material conditions, and the performance of stable molten catalysts. For catalytic methane cracking in molten catalysts (salt or metal), significant advancements in catalyst development, product separation, and reactor design are still needed to commercialize methane pyrolysis for hydrogen production. To provide guidance for future research, this review specifically focuses on catalyst design, recent developments in molten salt-based methane cracking, and reactor and process design.