The rapid increase of CO₂ in the atmosphere has caused serious environmental problems. Burning of biomass wastes increases the content of CO₂ in the environment. Herein, we propose a new strategy to convert biomass into photocatalysts for artificial CO₂ reduction. Using a hydrothermal method, carbohydrates from biomass can be converted into hydrothermal carbonaceous carbon (HTCC). The HTCC consists of plenty of sp²-hybridized structures, which are capable of absorbing solar light for photocatalytic CO₂ reduction. Furthermore, with the addition of Cu cocatalysts, higher activity can be obtained for CO₂ reduction. The activity of Cu-HTCC is 32 and 1.7 times higher than that of commercial TiO₂ and pure HTCC, respectively. This method provides a new strategy of trash to treasure, which converts biomass waste into photocatalysts for CO₂ reduction.

Keywords: CO2 reduction; biomass; copper; glucose; hydrothermal carbonaceous carbon; straw.