Ni-SiO₂ catalysts for the carbon dioxide reforming of methane: varying support properties by flame spray pyrolysis.

Emma Lovell,Rose Amal,Jason Scott

doi:10.3390/molecules20034594

Abstract

Silica particles were prepared by flame spray pyrolysis (FSP) as a support for nickel catalysts. The impact of precursor feed rate (3, 5 and 7 mL/min) during FSP on the silica characteristics and the ensuing effect on catalytic performance for the carbon dioxide, or dry, reforming of methane (DRM) was probed. Increasing the precursor feed rate: (i) progressively lowered the silica surface area from ≈340 m2/g to ≈240 m2/g; (ii) altered the silanol groups on the silica surface; and (iii) introduced residual carbon-based surface species to the sample at the highest feed rate. The variations in silica properties altered the (5 wt %) nickel deposit characteristics which in turn impacted on the DRM reaction. As the silica surface area increased, the nickel dispersion increased which improved catalyst performance. The residual carbon-based species also appeared to improve nickel dispersion, and in turn catalyst activity, although not to the same extent as the change in silica surface area. The findings illustrate both the importance of silica support characteristics on the catalytic performance of nickel for the DRM reaction and the capacity for using FSP to control these characteristics.

Highlights

The carbon dioxide reforming of methane (DRM) has been extensively investigated in recent decades
A higher precursor feed rate means a higher concentration of silica within the flame, in turn promoting sintering
Is clear is that the difference in surface properties of the flame spray pyrolysis (FSP)-prepared silica has an impact on the dispersion and Ni-support interaction, to a lesser extent than the impact of varying surface area. These findings demonstrate FSP is suitable for producing silica as a support for NiO catalysts with synthesis conditions able to be effectively tuned

Summary

Introduction

The carbon dioxide (dry) reforming of methane (DRM) has been extensively investigated in recent decades. The capacity for the reaction to consume the most destructive greenhouse gases (CO2 and CH4) to produce synthesis gas (H2 and CO; Equation (1)) make it a possible solution to some of the key anthropogenic issues facing society. Synthesis gas (syngas) can be used to produce liquid fuels such as methanol or diesel by the Fischer-Tropsch reaction and allow a transition to a more sustainable future. For catalysts to be utilised on an industrial scale they need to be active, selective and stable as well as economically viable. While noble metal based catalysts are more active and stable with reduced carbon formation [1,2] their costs limit commercial application. Ni provides a viable alternative from an economic perspective which promotes its favoritism as a catalyst in some cases

Results

Discussion

Conclusion