SYNTHESIS AND CHARACTERIZATION OF MIXED OXIDES BASED ON CERIUM AND NIOBIUM FOR APPLICATION IN BIOMASS CONVERSION
Biomass; synthesis methods; heterogeneous catalysts; and metal oxides.
The dependence on fossil fuels in the global energy matrix has triggered environmental and economic crises. To address these issues, the introduction of renewable and low-cost alternative resources, such as biomass, has emerged as a beneficial ally in mitigating climate change. Biomass, mainly composed of carbohydrates such as fructose, plays a crucial role in the production of industrially important chemicals, such as 5hydroxymethylfurfural. In this scenario, the advancement of selective and efficient catalytic systems for this purpose has been extensively researched, with a particular focus on heterogeneous catalysts, due to their multiple advantages, such as recovery and reuse. Therefore, in this study, several Ce and/or Nbbased oxides were synthesized by varying the theoretical niobium load by 5, 15 and 25%, using two synthesis methodologies: the glycerol-modified Pechini method and the metal-chitosan complexation method. The subsequent idea involves the exploitation of these materials in the conversion of biomass. Thus, in order to elucidate the structural, textural and electronic properties, the catalysts were widely characterized by the mid-infrared absorption spectroscopy (FTIR) technique, nitrogen physisorption analysis (by the BET and BJH methods), thermogravimetric analysis (TG/DTG), X-ray diffraction (XRD), Ultraviolet-Visible Diffuse Reflectance Spectroscopy (DRS), Raman spectroscopy and scanning electron microscopy (SEM).