Nickel Phosphide Catalysts as Efficient Systems for CO2 Upgrading via Dry Reforming of Methane

Miriam González-Castaño,Harvey Arellano-García,Qiang Wang,Laura Pastor-Pérez,Estelle Le Saché,Cameron Berry,Tomás Reina

doi:10.3390/catal11040446

Abstract

This work establishes the primordial role played by the support’s nature when aimed at the constitution of Ni2P active phases for supported catalysts. Thus, carbon dioxide reforming of methane was studied over three novel Ni2P catalysts supported on Al2O3, CeO2 and SiO2-Al2O3 oxides. The catalytic performance, shown by the catalysts’ series, decreased according to the sequence: Ni2P/Al2O3 > Ni2P/CeO2 > Ni2P/SiO2-Al2O3. The depleted CO2 conversion rates discerned for the Ni2P/SiO2-Al2O3 sample were associated to the high sintering rates, large amounts of coke deposits and lower fractions of Ni2P constituted in the catalyst surface. The strong deactivation issues found for the Ni2P/CeO2 catalyst, which also exhibited small amounts of Ni2P species, were majorly associated to Ni oxidation issues. Along with lower surface areas, oxidation reactions might also affect the catalytic behaviour exhibited by the Ni2P/CeO2 sample. With the highest conversion rate and optimal stabilities, the excellent performance depicted by the Ni2P/Al2O3 catalyst was mostly related to the noticeable larger fractions of Ni2P species established.

Highlights

The reduction of atmospheric carbon dioxide, and the greenhouse effect, is one of the defining scientific and engineering challenges of our time
Different hysteresis was noticed for the Ni2 P/CeO2 system, which presented type H3 isotherm shapes usually associated to aggregated particles
Compared to Ni2 P/Al2 O3 and Ni2 P/SiO2 -Al2 O3 catalysts, significantly lower surface areas were discerned for the Ni/CeO2 catalyst

Summary

Introduction

The reduction of atmospheric carbon dioxide, and the greenhouse effect, is one of the defining scientific and engineering challenges of our time. One technology with great potential in this field is the dry reforming of methane (DRM, CO2 + CH4 = 2CO + 2H2 ) to produce a mixture of carbon monoxide and hydrogen—syngas. Dry reforming was first studied by Fischer and Tropsch as early as 1928 [2], and today attracts ever increasing interest due to the rising importance of CO2 mitigation. Methane is a potent greenhouse gas, so the reduction of this pollutant in the atmosphere is highly desirable. The product syngas, as well as being a viable fuel for internal combustion [3], is an important feedstock for the production of higher hydrocarbon fuels through the Fischer Tropsch process [4] and for methanol production [5]

Objectives

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Conclusion