The confinement effects of ordered mesoporous carbon on copper nanoparticles for methanol oxidative carbonylation

Abstract

Copper nanoparticles confined in the mesopores of ordered mesoporous carbon (OMC) are prepared to catalyze methanol oxidative carbonylation, and the confinement effects on the properties of the catalysts are investigated. Using SBA-15 as the reverse-replicated template, OMC samples with ordered mesopore diameters between 3.6 nm and 5.1 nm are prepared via regulating the crystallizing temperature of SBA-15. Upon using these OMC materials to support nano-Cu catalysts, Cu nanoparticles are successfully confined in the ordered mesopores. Decreasing the mesopore size is found to be favorable for strengthening the Cu-carbon surface interactions, and for promoting electron shifts from the carbon surface towards the Cu nanoparticles, further facilitating the auto-reduction of CuO to active Cu₂O species. These confinement effects in the narrow mesopores further give rise to high and stable catalytic activity during the oxidative carbonylation of methanol. The average space-time yield of DMC over 10 h increases by 24.2% when the OMC mesopore diameter is decreased from 5.1 nm to 3.6 nm. This concept of decreasing the mesopore size to confine metal nanoparticles and to enhance the metal-support interactions can be further extended to the preparation of other metal-supported catalysts.