Impact of Daily Startup–Shutdown Conditions on the Production of Solar Methanol over a Commercial Cu–ZnO–Al 2 O 3 Catalyst

Methanol production with the use of syngas derived from solar‐driven splitting of CO 2 and H 2 O is a promising route to sustainable liquid fuels. Herein, we investigated the effect of using a CO 2 ‐rich syngas with the same composition as that obtained in a solar thermochemical reactor and of applying a daily startup–shutdown (DSS) routine matching the intermittent solar operation over a benchmark Cu–ZnO–Al 2 O 3 catalyst. The catalyst reached fast equilibration (10 h) in the presence of this syngas mixture and reversibly responded to changes in the concentrations of CO and CO 2 by mimicking fluctuations in the feed composition. Remarkably, its deactivation was even less pronounced over 27 cycles under a DSS regime than for a corresponding time on stream under uninterrupted operation if the reactor was purged with H 2 ‐free syngas upon shutdown. Characterization and modeling indicated that this purging avoided the formation of inactive ZnCO 3 and minimized the oxidation of the Cu surface atoms.