Nanomaterials (Oct 2021)

Support Induced Effects on the Ir Nanoparticles Activity, Selectivity and Stability Performance under CO<sub>2</sub> Reforming of Methane

  • Ersi Nikolaraki,
  • Grammatiki Goula,
  • Paraskevi Panagiotopoulou,
  • Martin J. Taylor,
  • Kalliopi Kousi,
  • Georgios Kyriakou,
  • Dimitris I. Kondarides,
  • Richard M. Lambert,
  • Ioannis V. Yentekakis

DOI
https://doi.org/10.3390/nano11112880
Journal volume & issue
Vol. 11, no. 11
p. 2880

Abstract

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The production of syngas (H2 and CO)—a key building block for the manufacture of liquid energy carriers, ammonia and hydrogen—through the dry (CO2−) reforming of methane (DRM) continues to gain attention in heterogeneous catalysis, renewable energy technologies and sustainable economy. Here we report on the effects of the metal oxide support (γ-Al2O3, alumina-ceria-zirconia (ACZ) and ceria-zirconia (CZ)) on the low-temperature (ca. 500–750 ∘C) DRM activity, selectivity, resistance against carbon deposition and iridium nanoparticles sintering under oxidative thermal aging. A variety of characterization techniques were implemented to provide insight into the factors that determine iridium intrinsic DRM kinetics and stability, including metal-support interactions and physicochemical properties of materials. All Ir/γ-Al2O3, Ir/ACZ and Ir/CZ catalysts have stable DRM performance with time-on-stream, although supports with high oxygen storage capacity (ACZ and CZ) promoted CO2 conversion, yielding CO-enriched syngas. CZ-based supports endow Ir exceptional anti-sintering characteristics. The amount of carbon deposition was small in all catalysts, however decreasing as Ir/γ-Al2O3 > Ir/ACZ > Ir/CZ. The experimental findings are consistent with a bifunctional reaction mechanism involving participation of oxygen vacancies on the support’s surface in CO2 activation and carbon removal, and overall suggest that CZ-supported Ir nanoparticles are promising catalysts for low-temperature dry reforming of methane (LT-DRM).

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