Identification of the Active Sites on Metallic MoO2-x Nano-Sea-Urchin for Atmospheric CO2 Photoreduction Under UV, Visible, and Near-Infrared Light Illumination.

Abstract

We report an oxygen vacancy (Vo )-rich metallic MoO2-x nano-sea-urchin with partially occupied band, which exhibits super CO2 (even directly from the air) photoreduction performance under UV, visible and near-infrared (NIR) light illumination. The Vo -rich MoO2-x nano-sea-urchin displays a CH4 evolution rate of 12.2 and 5.8 μmol gcatalyst -1 h-1 under full spectrum and NIR light illumination in concentrated CO2 , which is ca. 7- and 10-fold higher than the Vo -poor MoO2-x , respectively. More interestingly, the as-developed Vo -rich MoO2-x nano-sea-urchin can even reduce CO2 directly from the air with a CO evolution rate of 6.5 μmol gcatalyst -1 h-1 under NIR light illumination. Experiments together with theoretical calculations demonstrate that the oxygen vacancy in MoO2-x can facilitate CO2 adsorption/activation to generate *COOH as well as the subsequent protonation of *CO towards the formation of CH4 because of the formation of a highly stable Mo-C-O-Mo intermediate.