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The study describes the synthesis of Mg-Al hydrotalcite (Ht) with the use of starch as a structure controlling biotemplate. Syntheses were carried out at room temperature, by co-precipitation at pH = 10. The investigated synthesis parameters included the nature of the precipitating agent (NaOH/Na2CO3 or NH3aq/(NH4)2CO3), the nature of starch (potato, corn and cassava), the method of starch addition to reagents, the method of drying and the effect of washing. The materials were examined with X-ray diffraction, scanning electron microscopy/energy dispersive X-ray spectroscopy and infrared spectroscopy. The data show that synthesis of Ht materials in the presence of starch, with use of the ammonia-based precipitant, enabled preparation of nanocrystalline Ht with very fine (<50 nm) particle size. All investigated starches had a similar effect on the crystallinity and the grain size of Ht precipitates. Ht with the smallest nanocrystals was obtained when starch was present in all solutions used for synthesis, and the final product subjected to freeze drying. Washing with water was found to enhance recrystallization and exchange of nitrates for carbonates. Infrared spectra showed that an interaction exists between the biopolymer template and the Ht particles, resulting in a higher degree of order within the Ht-adhering starch component.

Within the Waste2Fuel project, innovative, high-performance, and cost-effective fuel production methods from municipal solid wastes (MSWs) are sought for application as energy carriers or direct drop-in fuels/chemicals in the near-future low-carbon power generation systems and internal combustion engines. Among the studied energy vectors, C1-C2 alcohols and ethers are mainly addressed. This study presents a potential bio-derived ethanol oxidative coupling in the gas phase in multicomponent systems derived from hydrotalcite-containing precursors. The reaction of alcohol coupling to ethers has great importance due to their uses in different fields. The samples have been synthesized by the co-precipitation method via layered double hydroxide (LDH) material synthesis, with a controlled pH, where the M(II)/M(III) ≈ 0.35. The chemical composition and topology of the sample surface play essential roles in catalyst activity and product distribution. The multiple redox couples Ni2+/Ni3+, Cr2+/Cr3+, Mn2+/Mn3+, and the oxygen-vacant sites were considered as the main active sites. The introduction of Cr (Cr3+/Cr4+) and Mn (Mn3+/Mn4+) into the crystal lattice could enhance the number of oxygen vacancies and affect the acid/base properties of derived mixed oxides, which are considered as crucial parameters for process selectivity towards bio-DEE and bio-butanol, preventing long CH chain formation and coke deposition at the same time.

Composites of Laponite and Cu–Mn hopcalite-related mixed oxides, prepared from hydrotalcite-like (Htlc) precursors obtained in inverse microemulsions, were synthesized and characterized with XRF, XRD, SEM, TEM, H2 temperature-programmed reduction (TPR), and N2 adsorption/desorption at −196 °C. The Htlc precursors were precipitated either with NaOH or tetrabutylammonium hydroxide (TBAOH). Al was used as an element facilitating Htlc structure formation, and Ce and/or Zr were added as promoters. The composites calcined at 600 °C are mesoporous structures with similar textural characteristics. The copper–manganite spinel phases formed from the TBAOH-precipitated precursors are less crystalline and more susceptible to reduction than the counterparts obtained from the precursors synthesized with NaOH. The Cu–Mn-based composites are active in the combustion of toluene, and their performance improves further upon the addition of promoters in the following order: Ce < Zr < Zr + Ce. The composites whose active phases are prepared with TBAOH are more active than their counterparts obtained with the use of the precursors precipitated with NaOH, due to the better reducibility of the less crystalline mixed oxide active phase.