A novel catalyst system for methane decomposition

Abstract

Summary Bulk of present day hydrogen comes from gasification of coal, steam reforming, and partial oxidation of hydrocarbons. Steam reforming accounts for over 50% of world hydrogen production despite producing carbonaceous gases which are harmful to the environment. In this work, five different supported molten metal catalysts comprising varying quantities of nickel and lithium supported on calcium oxide were synthesized and designated according to weight % as; 50%Ni/CaO, 37.5%Ni‐12.5%Li/CaO, 25.0%Ni‐25.0%Li/CaO, 12.5%Ni‐37.5%Li/CaO, and 50%Li/CaO. The synthesized catalysts were characterized by scanning electron microscopy, X‐ray diffraction, Brunauer‐Emmett‐Teller, and transmission electron microscopy and tested for methane decomposition. During decomposition experiments, the performance of each catalyst under different temperature conditions was evaluated in terms of methane conversion, carbon, and hydrogen yield. From experimental data obtained, catalyst 37.5%Ni‐12.5%Li/CaO recorded 65.7% methane conversion and 38.3%hydrogen yield, while catalyst 50%Ni/CaO recorded the lowest methane conversion of 60.2% and a hydrogen yield of 35.7% at 650°C. This confirms that the molten environment aided catalyst activity in methane decomposition reaction.

Enhanced selectivity of syngas in partial oxidation of methane: A new route for promising Ni‐alumina catalysts derived from Ni/ γ‐AlOOH with modified Ni dispersion

“…Addition of rhodium and rhenium was also found to enhance nickel reducibility leading to an increase in the CH 4 conversion during partial oxidation reactions 13‐15 . Different other metal promotors have also shown significant impact on the performance of Ni catalysts 16‐20 …”

“…Improving the performance of Ni catalysts by incorporation of other metals has been the focus of a large number or recent studies where enhanced catalytic performance has been reported. [10][11][12][13][14][15][16][17][18][19][20] Doping Ni catalysts with Ru, as an example, has been reported to hinder surface carbon deposition and to enhance the catalyst stability in POM with tunable H 2 /CO ratio. 10 The addition of Ru to the Ni catalyst was also found to accelerate carbon gasification.…”

“…[13][14][15] Different other metal promotors have also shown significant impact on the performance of Ni catalysts. [16][17][18][19][20] Coke formation during CH 4 partial oxidation and other reforming reactions over Ni catalysts has been found to be one of the main causes of catalysts' deactivation. It is well accepted that such carbon deposits originate from CO disproportionation and CH 4 decomposition reactions shown in Equations (2) and (3) below 21 :…”

Thermochemical waste-heat recuperation by steam methane reforming with flue gas addition

“…In the methane reformer, methane, steam, and carbon dioxide (from combustion products) are reformed due to endothermic reaction: (a) steam methane reforming and (b) dry methane reforming (DMR), to the synthesis gas that is called the synthetic fuel or synfuel. The reaction space of the reformer is activated by the nickel‐based or other catalysts …”

Methane Decomposition Over ZrO2-Supported Fe and Fe–Ni Catalysts—Effects of Doping La2O3 and WO3

“…This was aimed at reducing the operating cost of the whole process, and thus, reduction of the catalysts in the gas feed stream was performed. However, the hydrogen yields for such processes were reported to be low (Enakonda et al, 2016;Musamali and Isa, 2018).…”