Photocatalytic CO_2 Reduction in Gas-Solid Regime in the Presence of Bare, SiO_2 Supported or Cu-Loaded TiO_2 Samples

摘要

Both commercial and home prepared (HP) TiO_2 samples have been tested for the photocatalytic reduction of CO_2. (HP) TiO_2 powders were prepared by using TiCl_4 or Ti(OC_4H_9)_4 as the precursors to obtain HP1 and HP2 samples, respectively. Also HP Cu-loaded and SiO_2 supported TiO_2 powders were prepared. The HP samples were more active than the commercial ones for the photoreduction of CO_2 with and without water vapour. HP1 produced mainly formaldehyde, HP2 principally methane. Acetaldehyde was found to be the primary product obtained when HP1 was supported on SiO_2. The addition of Cu increased the photocatalytic reactivity either of bulk and SiO_2-supported HP1. In particular, 1 wt % of Cu improved the formaldehyde yield obtained with the bare HP1 by one order of magnitude. Differently, the presence of Cu or SiO_2 in the HP2 samples markedly reduced the production of methane.