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

Abstract

A leading method for hydrogen production that is free of carbon oxides is catalytic methane decomposition. In this research, Fe and Fe-Ni supported catalysts prepared by the wet impregnation method were used in methane decomposition. The effects of doping the parent support (ZrO 2) with La 2 O 3 and WO 3 were studied. It was discovered that the support doped with La 2 O 3 gave the best performance in terms of CH 4 conversion, H 2 yield, and stability at the test condition, 800 • C and 4,000-ml h −1 g −1 cat. space velocity. The addition of Ni significantly improved the performance of all the monometallic catalysts. The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), temperature-programmed reduction/oxidation (TPR/TPO), thermogravimetric analyzer (TGA), and microscopy (SEM and Raman) techniques. Phases of the different forms of Fe were identified by XRD. BET showed a drastic decline in the specific surface area of the catalysts with respect to the supports. TPR profiles revealed a progressive change in the valency of Fe in its combined form to the zero valence-free metal. The La 2 O 3-promoted support gave the best performance and maintained good stability during the time on stream.

Methane decomposition into CO x ‐free hydrogen over a Ni‐based catalyst: An overview

“…After passing this initial stage, hydrogen production and methane conversion gradually become stable with time on stream. In the case of the Fe promoter, improved stability at a given reaction time also was achieved in case of Ni‐Fe/ZrO 2 23,94 and Ni‐Fe/Al 2 O 3. 21 The addition of the second element as a promoter for Ni affords an alloy catalyst, which enhances the catalytic activity and stability, and the metal alloy increases the carbon diffusion rate and subsequently prevents deactivation 95 .…”

“…As oxide supports, metal oxides such as Al 2 O 3, 21,80,97,107 TiO 2, 108,109 SiO 2, 79,110‐114 MgO, 101,115 CeO 2, 100,116 ZrO 2, 23,94 and zeolite 22,104 are frequently used for a Ni‐based catalyst. In practice, active metal particles must be dispersed onto the oxide support surface.…”

“…Catalyst performance is directly affected by the synthesis method, and the dispersion of metal particles on the support, particle size, and type of MSI considerably depend on the synthesis method. Synthesis methods that can produce an active and a stable Ni‐based catalyst for the CMD reaction include impregnation, 19,21‐23,60,77‐80,84,96,100,101,103,104,109‐111,114,127‐130 precipitation, 76,87,95,105,112,131‐134 and the sol‐gel method 67,68,94,97,108,116 . In addition, polyol reduction, 113,118,135 EISA, 85,115 fusion, 82 and emulsion 136 are employed.…”

“…Based on the raw material, methods to produce hydrogen can be categorized as conventional (fossil fuel) or renewable. Some examples of conventional hydrogen production methods include steam methane reforming, 2‐15 partial oxidation reforming, 16‐18 and methane pyrolysis, including nonoxidative catalytic methane decomposition (CMD) 19‐23 . Examples of renewable hydrogen production methods include electrolysis 24‐27 and photocatalysis 28‐30 .…”

Hydrogen production from CO2 reforming of methane using zirconia supported nickel catalyst

“… 23 Fakeeha et al ; studied the effect of doping La 2 O 3 and WO 3 on the decomposition of methane by the Fe–Ni catalyst over the ZrO 2 support. 24 Their study revealed that the La 2 O 3 doped ZrO 2 support resulted in the maximum decomposition of methane to hydrogen with relatively high stability. Zhang et al ; investigated the stabilization of the metastable structure of ZrO 2 by reflux treatment and the improvement of Ni/ZrO 2 catalyst for CRM.…”