Thiol-assisted aerosol synthesis of mesoporous Cu–SiO2 catalysts for effective and stable ethanol dehydrogenation

Abstract

Supported copper nanoparticles play a fundamental role in heterogeneous sustainable catalysis, particularly for the conversion of biomass-derived feedstocks (such as bioethanol) to platform chemicals. However, controlling their fine dispersion and, at the same time, their resistance to sintering remains a challenge, especially when using silica supports. We report a simple one-pot aerosol route to produce mesoporous Cu–SiO₂ catalysts featuring small copper nanoparticles (2–4 nm) partially embedded in the silica matrix. To achieve this, we exploit the affinity between the copper and the thiol function of a mercapto-silane: (3-mercaptopropyl)-trimethoxysilane (MPTMS). As supported by characterization (in particular XRD, XPS, TEM, TPR, UV-VIS, and dispersion measurements) the addition of this molecule during synthesis markedly enhanced Cu dispersion in the calcined catalyst. This is shown to translate into enhanced time-on-stream stability during the ethanol non oxidative dehydrogenation to acetaldehyde. The catalyst obtained via thiol-assisted stabilization of copper demonstrates a sustained acetaldehyde productivity of 2.88 g_aca g_cat⁻¹ h⁻¹ during 23 h test time at 623 K.