Nanostructured Nickel Aluminate as a Key Intermediate for the Production of Highly Dispersed and Stable Nickel Nanoparticles Supported within Mesoporous Alumina for Dry Reforming of Methane.

Leila Karam,Jaysen Nelayah,Nissrine El Hassan,Julien Reboul,Pascale Massiani

doi:10.3390/molecules24224107

Abstract

Two routes of preparation of mesoporous Ni-alumina materials favoring the intermediate formation of nanostructured nickel-aluminate are presented. The first one involves an aluminum containing MOF precursor used as sacrificial template to deposit nickel while the second is based on a one-pot synthesis combined to an EISA method. As shown by a set of complementary techniques, the nickel-aluminate nanospecies formed after calcination are homogeneously distributed within the developed mesoporous alumina matrices whose porous characteristics vary depending on the preparation method. A special attention is paid to electron-microscopy observations using especially STEM imaging with high chemical sensitivity and EDS elemental mapping modes that help visualizing the extremely high nickel dispersion and highlight the strong metal anchoring to the support that persists after reduction. This leads to active nickel nanoparticles particularly stable in the reaction of dry reforming of methane.

Highlights

Dry reforming of methane (DRM), a reaction that converts CH4 and CO2 into a mixture of CO
The shape of the isotherm drastically differs for the Ni5wt% -Al2 O3-evaporation induced self-assembly (EISA) material that was prepared in presence of amphiphilic block copolymers assemblies as structuring agent
In view of this work, key features for preparing nickel alumina catalysts with high efficiency and stability for dry reforming of methane consists of: (i) preparing a nanostructured mesoporous hybrid material within which nickel cations efficiently dispersed in contact with the alumina precursors, (ii) calcining the material to remove the organic part and (iii) reducing at high temperature to form small and stable Ni0 nanoparticles anchored to the mesoporous alumina support

Summary

Introduction

Dry reforming of methane (DRM), a reaction that converts CH4 and CO2 into a mixture of CO and H2 (synthesis gas), is gaining significant attention in the research sector. This process uses CH4 and CO2 (greenhouse gases) extracted from natural reserves or produced from renewable sources such as municipal solid wastes, and converts them into valuable syngas that is a feedstock for the production of synthetic fuels and of chemical intermediates in petrochemical industries. The main problem that plagues this reaction from reaching the industrial scale is the challenges faced upon constructing an active and stable catalyst. The drawback of such catalysts is their tendency to deactivate at the high reaction temperatures

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