Hydrogen production by thermo-catalytic decomposition of methane: Regeneration of active carbons using CO2

Direct decomposition of methane over Pd promoted Ni/SBA-15 catalysts

“…Currently, global energy 26 production is based on the combustion of non-renewable fossil fuels, which are continuously 27 being depleted due to their excessive usage [1], further impacting the environment. The 28 combustion of fossil fuels primarily results in the generation of a large amount of greenhouse 29 gases such as carbon, nitrogen and sulfur oxides.…”

Kinetic study of the thermal decomposition of methane using carbonaceous catalysts

“…It has been previously reported [17][18][19] that the surface oxygen groups play a key role in the initial reaction rate. Methane thermal decomposition is a free radical process where methane molecules become attached to the active sites present on the carbon surface, the operation of such mechanism is confirmed by the existence of enough stable free radicals on the pyrolitic carbon surface [32]; (2) a pseudo steady state, which is governed by the activity of the crystallites produced from methane; Muradov [5] reported that at certain conditions carbon produced by thermal decomposition of methane would be able to catalyze the process.…”

“…This fact means that the activated carbon has a catalytic effect on the methane decomposition reaction. The CG Norit sample has a high amount of oxygen surface groups, which are known to play an important role in the initial stage of the methane decomposition reaction [17][18][19]. However, this catalytic effect is rapidly inhibited by the deposition of crystallites from methane, which apparently did not show activity towards methane decomposition.…”

“…In a second stage [18], different carbonaceous samples, carbon blacks, showing an external surface area, open and easily accessible to methane molecules were studied as a possible way of delaying the rapid deactivation observed for the activated carbons. In fact, catalyst deactivation is one of the main drawbacks for the use of carbonaceous materials as catalysts for hydrogen production by TCD of methane and so that, in a previous work [19] the evolution of a selected carbon catalyst during successive cycles of TCD of methane and regeneration of the deactivated carbon particles, using CO 2 as activating agent was also studied. The optimum operation conditions for catalysts regeneration were evaluated considering both, the regeneration of surface area and oxygenated surface groups which are essential to reactivate the catalysts and the burn off of the carbon sample, which is essential for the sustainability of the process.…”

Carbonaceous materials as catalysts for decomposition of methane

“…Two different nature catalysts have been used for this process: metallic and carbonaceous catalysts [6][7][8][9]. Carbon catalysts were proposed as an alternative to metallic catalysts [10][11][12][13][14][15][16] because they offer several advantages: (i) higher fuel flexibility and no sulphur poisoning; (ii) lower price; (iii) the carbon formed can be used as catalyst precursor, so that the process is self-sustained.…”