Enhanced Methanol Production over Non-promoted Cu–MgO–Al₂O₃ Materials with Ex-solved 2 nm Cu Particles: Insights from an Operando Spectroscopic Study

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