Ni-Fe Bimetallic Catalysts Prepared For Decomposition Of Methane

Catalytic methane decomposition（CMD）is a green,eco-friendly,efficient and clean pathway for hydrogen production with simple reactions,only two products（hydrogen and carbon materials with commercialization potential）,easy separation and has attracted a lot of attention in the industry.Currently,CMD technology is still in the laboratory research stage,where the design and preparation of efficient and stable catalysts is a critical challenge for CMD technology.In this paper,loaded bimetallic nickel-iron catalysts were prepared by mechanical grinding and fusion methods using nickel foam as precursors,and the effects of different metal loading,calcination temperature（600-850 ^oC）and reaction temperature（600-850 ^oC）on the performance of nickel foam-based bimetallic catalysts in CMD reactions were studied and investigated.The nickel foam-based bimetallic catalysts were also analytically characterized before and after the CMD reaction.The results indicated that the bimetallic nickel-iron catalysts prepared by both preparation methods exhibited excellent catalytic performance when the loading of nickel was 11 wt%and the loading of iron was 25 wt%.The reaction temperature of850 ^oC is more favorable for the reaction performance of the catalyst.The calculation temperature of 700 ^oC is more convenient for the catalytic activity of the catalysts prepared by mechanical grinding method,while 600 ^oC is more suitable for releasing the catalytic activity of the catalysts prepared by fusion method.Among them,the F-11Ni-25Fe-600 sample prepared by the fusion method has high catalytic activity in the CMD reaction,and the Ni O and Fe₂O₃components in this sample can form Ni-Fe alloy under the action of methane and hydrogen atmosphere in the CMD reaction,which improves the activity and stability of the catalyst(the carbon accumulation can reach 24.3 g _C/g _Ni).The methane conversion of 95%was achieved after 600 min of CMD reaction.The deposited carbon after the reaction was highly graphitized（I_D/I_G of 0.38）and exhibited a carbon fiber morphology.Under the above optimized catalyst preparation conditions,the catalyst samples with nickel nitrate as precursor were prepared by mechanical grinding and fusion methods,and the CMD performance was investigated in a fixed-bed reactor.The experimental results revealed that the reactivity and stability of the F-11Ni_a-25Fe-600 sample prepared by the Fusion method were well established(up to 19.1 g _C/g _Ni of carbon accumulation).After 600 min of CMD reaction,the methane conversion reached 90%and the graphitization of the deposited carbon after the reaction was relatively high（I_D/I_G of 0.44）,which could also exhibit carbon fiber morphology.This research idea enriches and develops the feedstock sources for efficient nickel-based catalysts for hydrogen production from methane decomposition.