Nanostructured materials based on LaNixFe1-xO3-d perovskites supported on CeO2-ZrO2 mixed oxides for dry reforming of methane

MURIEL MACORETTA; D.G. LAMAS; S.A. LARRONDO.; L. M. TOSCANI

Buenos Aires

Congreso; 11th World Congress on Chemical Engineering; 2023

Biogas production from anaerobic fermentation of biomass stands as a sustainable alternative to produce energy. However, the conversion of this low calorific power fuel into a high-value product such as synthesis gas (H2+CO, Syngas) remains a major challenge. Syngas can be used as a raw material in the production of several chemical products such as methanol and in the production of liquid fuels through the Fischer Tropsch process. Moreover, Syngas is used in solid oxide fuel cells (SOFCs) for energy production with high efficiency and lower carbon footprint compared to current direct combustion technologies. Biogas revalorization into syngas can be achieved by heterogeneous catalysis through dry reforming of methane (DRM). Nonetheless, traditional noble metals or supported Ni Ni-based catalysts are rapidly deactivated by carbon formation. Thus, the development of new materials is focused on the design of highly active, selective, and stable catalysts in operating conditions. In this regard, LaNixMe1-xO3-δ (Me=Sr, Co, Cu, Fe) perovskite-type materials stand as a potential alternative due to their capacity to exsolve Ni from their structure in a reducing environment, generating in-situ a highly disperse Ni active phase with an excellent interaction with the support.In this work, we present the results of the development of LaNixFe1-xO3-δ (LNFO) perovskite-type catalysts supported on a CeO2-ZrO2 (CZ) mixed oxide for DRM. CZ, LNFO, and LNFO/CZ samples were synthesized via a soft chemical route that involves cation complexation with citric acid. Structural characterization was performed via x-ray powder diffraction (XRD), and redox characterization was performed via temperature temperature-programmed reduction with diluted H2 (H2-TPR). Catalytic tests were carried out in a conventional quartz fixed-bed reactor operated isothermally, at atmospheric pressure, with inlet and outlet gas compositions determined by oin-line Gas Chromatography (TCD).XRD results confirm the formation of LNFO perovskite phase and fluorite phase from CZ without the formation of secondary phases. After a reducing treatment in 50%H2/N2 at 700°C, the exsolution of nano metallic Ni took place over the perovskite surface with the concomitant partial segregation of La2O3. Catalytic activity results show that at temperatures lower than 750°C, sample LNFO exhibits higher methane conversion values in contrast to those of sample LNFO/CZ. However, this trend is reversed markedly at temperatures higher than 750°C. In addition, CO and H2 yield results reveal that sample LNFO/CZ exhibits a much higher selectivity to these products in the whole temperature range compared to LNFO sample. Thus, sample LNFO/CZ stands as a promising alternative as an active, selective, and carbon-resistant catalyst for DRM.