K2CO3-promoted methane pyrolysis on nickel/coal-char hybrids

Methane Cracking for Hydrogen Production: A Review of Catalytic and Molten Media Pyrolysis

“…Different types of carbonaceous catalysts, such as activated char [24], biochar [24], coal char [27], carbon black [23,79], etc., have been studied for methane pyrolysis. They present several advantages over metallic catalysts: (i) lower cost, (ii) higher resistance to high temperature, (iii) safe storage, (iv) tolerance to impurities as sulfur, (v) no contamination of the carbon byproduct, (vi) generally no need for regeneration, (vii) additional self-catalytic effects of the produced carbon, and (viii) mitigation of CO 2 emissions, compared with metals, because the regeneration of metallic catalysts requires burning of the C on their surfaces which emits CO/CO 2 [24,80,81].…”

Methane Pyrolysis for CO2‐Free H2 Production: A Green Process to Overcome Renewable Energies Unsteadiness

“…Carbon materials usually exhibit lower catalytic activity than metal catalysts and must operate at relatively high temperatures of around 800-1100°C to achieve good hydrogen yields [116]. Nevertheless, carbon catalysts show important advantages that overcome the problems attributed to metal catalysts [17,20,117]: -lower cost -higher resistance to temperature and better stability -safe storage of the carbon product due to non-toxicity -tolerance to impurities, e.g., sulfur resistance -no contamination of the carbon by-product with metal particles -mitigation of CO 2 emissions (unlike metal catalysts: the regeneration of metal catalysts by burning the carbon accumulated on the catalyst surface produces significant amounts of CO x ) -the produced carbon may also have some catalytic effects -no need for catalyst regeneration Different carbon materials have been investigated for the thermal decomposition of methane: activated carbon (AC), carbon black (CB), glassy carbon, acetylene black, graphite (graph), diamond powder, coal char, fullerene soot, fullerenes C 60/70 , carbon nanotubes, and ordered mesoporous carbons (CMK materials). According to their crystallinity, carbon materials are classified into highly ordered (graphite and diamond), less ordered (turbostratic and pyrolytic carbon, such as glassy carbon, fullerene soot, fullerenes C 60/70 , carbon nanotubes, and CMK materials), and disordered (amorphous, microcrystalline, such as activated carbon, carbon black, coal char, and acetylene black) carbons [23,79].…”

“…Carbon materials usually exhibit lower catalytic activity than metal catalysts and must operate at relatively high temperatures of around 800–1100 °C to achieve good hydrogen yields . Nevertheless, carbon catalysts show important advantages that overcome the problems attributed to metal catalysts , , : lower cost higher resistance to temperature and better stability safe storage of the carbon product due to non‐toxicity tolerance to impurities, e.g., sulfur resistance no contamination of the carbon by‐product with metal particles mitigation of CO 2 emissions (unlike metal catalysts: the regeneration of metal catalysts by burning the carbon accumulated on the catalyst surface produces significant amounts of CO x ) the produced carbon may also have some catalytic effects no need for catalyst regeneration …”

Methane Pyrolysis for Zero-Emission Hydrogen Production: A Potential Bridge Technology from Fossil Fuels to a Renewable and Sustainable Hydrogen Economy

“…In addition to this, the combustion of hydrogen originates more energy on a mass basis than conventional fossil fuels. , Hydrogen has received special attention for its application in fuel cells and internal combustion engines, enabling the creation of a low-carbon hydrogen economy . The chemical energy of hydrogen can be efficiently converted to electricity and other energy forms without GHG emissions. ,,, Hydrogen also plays a major role in the development of new strategies for converting industrial CO 2 emissions into important platform chemicals. This is actually one of the objectives set within the Carbon2Chem project, which aims to convert steel mill gases into base chemicals such as methanol. , Thereby, the transformation of industrial emissions into chemicals prevents the release of GHG into the atmosphere.…”