H2 Production from Catalytic Methane Decomposition Using Fe/x-ZrO2 and Fe-Ni/(x-ZrO2) (x = 0, La2O3, WO3) Catalysts

Fahad Al-Mubaddel,Ahmed A Ibrahim,Anis H Fakeeha,Abdulrhman S Al-Awadi,Samsudeen Kasim,Ahmed S Al-Fatesh

doi:10.3390/catal10070793

Abstract

An environmentally-benign way of producing hydrogen is methane decomposition. This study focused on methane decomposition using Fe and Fe-Ni catalysts, which were dispersed over different supports by the wet-impregnation method. We observed the effect of modifying ZrO2 with La2O3 and WO3 in terms of H2 yield and carbon deposits. The modification led to a higher H2 yield in all cases and WO3-modified support gave the highest yield of about 90% and was stable throughout the reaction period. The reaction conditions were at 1 atm, 800 °C, and 4000 mL(hgcat)−1 space velocity. Adding Ni to Fe/x-ZrO2 gave a higher H2 yield and stability for ZrO2 and La2O3 + ZrO2-supported catalysts whose prior performances and stabilities were very poor. Catalyst samples were analyzed by characterization techniques like X-ray diffraction (XRD), nitrogen physisorption, temperature-programmed reduction (TPR), thermo-gravimetric analysis (TGA), and Raman spectroscopy. The phases of iron and the supports were identified using XRD while the BET revealed a significant decrease in the specific surface areas of fresh catalysts relative to supports. A progressive change in Fe’s oxidation state from Fe3+ to Fe0 was observed from the H2-TPR results. The carbon deposits on Fe/ZrO2 and Fe/La2O3 + ZrO2 are mainly amorphous, while Fe/WO3 + ZrO2 and Fe-Ni/x-ZrO2 are characterized by graphitic carbon.

Highlights

Hydrogen has been touted to be the energy of the future, as it burns cleanly without introducing any pollutant to the environment
It has a calorific value that is thrice that of traditional fuel [1]. It could as well substitute for fossil fuel in the near future
We studied the conversion of methane over these catalysts [22]

Summary

Introduction

Hydrogen has been touted to be the energy of the future, as it burns cleanly without introducing any pollutant to the environment. It has a calorific value that is thrice that of traditional fuel (e.g., gasoline) [1]. It could as well substitute for fossil fuel in the near future. Hydrogen happens to be the lightest and most plentiful element. It accounts for 74% or thereabouts of the whole universe [2]. The green solar energy that we obtain from the sun originates from the fusion of hydrogen. The provision of hydrogen by the sun will be enough to keep the fusion reaction going on for more than 5 × 109 years [3]

Methods

Results

Conclusion