Mesoporous Silica-Encapsulated Cu Nanoparticles with Enhanced Performance for Ethanol Dehydrogenation to Acetaldehyde

The selective dehydrogenation of ethanol to acetaldehyde over copper-based catalysts is a highly desirable solution for biomass valorization but with a significant challenge of severe deactivation caused by Cu sintering. Herein, a series of mesoporous silica-encapsulated nano-Cu catalysts (Cu@mSiO2) with different Cu loadings of 1–7 wt % were prepared via a modified Stöber method for ethanol dehydrogenation to acetaldehyde. The as-synthesized Cu@mSiO2 catalysts were characterized by XRD, N2 adsorption, SEM, TEM, XPS, and TPR. The 7Cu@mSiO2 catalyst exhibits a stable acetaldehyde yield of around 84% over 100 h on stream at 260 °C and a WHSV of 1.5 h–1, stemming from the spatial confinement effect of the mesoporous silica shell on the Cu nanoparticles. Cu+ and Cu0 species coexisting on the catalyst conduct as synergistic dual active sites for the titled reaction. The acetaldehyde productivity can be controlled by adjusting the Cu+/(Cu0 + Cu+) ratio on catalysts.