Enhanced methanol production is obtained over a non-promoted Cu–MgO–Al₂O₃ mixed oxide catalyst derived from a Cu–Mg–Al hydrotalcite precursor (HT) containing narrowly distributed small Cu NPs (2 nm). Conversions close to the equilibrium (∼20%) with a methanol selectivity of 67% are achieved at 230 °C, 20 bar, and a space velocity of 571 mL·g_cat^–1·h^–1. Based on operando spectroscopic studies, the striking activity of this Cu-based catalyst is ascribed to the stabilization of Cu⁺ ions favored under reaction conditions due to lattice reorganization associated with the “HT-memory effect” promoted by water. Temperature-resolved infrared–mass spectrometry experiments have enabled the discernment of monodentate formate species, stabilized on Cu⁺ as the intermediate in methanol synthesis, in line with the results of density functional theory calculations. These monodentate formate species are much more reactive than bridge formate species, the latter ones behaving as intermediates in methane and CO formation. Moreover, poisoning of the Cu⁰ surface by strongly adsorbed species behaving as spectators is observed under reaction conditions. This work presents a detailed spectroscopic study highlighting the influence of the reaction pressure on the stabilization of active surface sites, and the possibility of enhancing methanol production on usually less active non-promoted nano-sized copper catalysts, provided that the proper support is selected, allowing the stabilization of doped Cu⁺. Thus, a methanol formation rate of 2.6 × 10^–3 mol_MeOH·g_cat^–1·h^–1 at 230 °C, 20 bar, and WHSV = 28 500 mL·g_cat^–1·h^–1 is obtained on the Cu–MgO–Al₂O₃ HT-derived catalyst with 71% methanol selectivity, compared to 2.2 × 10^–4 mol_MeOH·g_cat^–1·h^–1 with 54% methanol selectivity obtained on a reference Cu/(Al₂O₃/MgO) catalyst not derived from a HT structure.

One of the key reactions to achieve good productivity in the transformations of cellulose derived from biomass feedstocks is the isomerization of glucose to fructose, the latest being the platform molecule for obtaining other important derivatives. In this work, Ca–Al containing catalysts based on hydrotalcite-type derived materials were used to perform the selective isomerization of glucose to fructose, and the selective epimerization of glucose to mannose, using water as the solvent under mild reaction conditions. The catalysts showed high activity (conversion = 51–87%), and excellent selectivity (63–88%) towards fructose, compared with the current industrial process based on the glucose transformation via biocatalysis. It was also possible to modulate the selectivity towards fructose or mannose by tuning the amount of basic sites of the catalysts and their composition. The combination of basic and acid sites present in the Ca–Al-based catalysts plays a key role in the reaction, a fact that is discussed in the text together with other important operational parameters. The stability and recyclability of the catalysts were tested, detecting only a small activity loss after 5 consecutive runs. The synthesis of the catalysts and their characterization are also discussed since they are one of the few cases found in the literature of this kind of hydrotalcite-type material with such a high level of Ca incorporation. Some green metrics, such as E-factor, have been calculated to evaluate our system as an environmentally friendly process.