High-efficiency photoreduction of CO₂ in a low vacuum

Photoreduction of CO₂ into CO, CH₄ or hydrocarbons is attractive, due to environmental compatibility and economic feasibility. Optimizing the reaction engineering of CO₂ reduction is an effective and general strategy that should be given special consideration. In this article, the photocatalytic CO₂ reduction performances are originally investigated in a low vacuum in both dilute (10%) and pure CO₂. We discover that the CH₄ yield increased above one hundred times as the vacuum degree increased from barometric pressure to -80 kPa in dilute CO₂. It also reveals long-term stability and good cycling performance in a low vacuum. The enhanced CO₂ 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 CO₂ reduction in a low vacuum is further verified by Pt-TiO₂ catalysts. This research presents a general route for producing clean fuels by photocatalytic CO₂ reduction in a more effective way.