High-efficiency photoreduction of CO 2 in a low vacuum.

Photoreduction of CO 2 into CO, CH 4 or hydrocarbons is attractive, due to environmental compatibility and economic feasibility. Optimizing the reaction engineering of CO 2 reduction is an effective and general strategy that should be given special consideration. In this article, the photocatalytic CO 2 reduction performances are originally investigated in a low vacuum in both dilute (10%) and pure CO 2 . We discover that the CH 4 yield increased above one hundred times as the vacuum degree increased from barometric pressure to -80 kPa in dilute CO 2 . It also reveals long-term stability and good cycling performance in a low vacuum. The enhanced CO 2 photoreduction performance in a low vacuum comes from better accumulation of photogenerated electrons, less intense Brownian movement of gas molecules in the environment and hindrance of the active site-blocking of gas molecules in the environment. Improved photocatalytic CO 2 reduction in a low vacuum is further verified by Pt-TiO 2 catalysts. This research presents a general route for producing clean fuels by photocatalytic CO 2 reduction in a more effective way.