Efficient Hole Trapping in Carbon Dot/Oxygen‐Modified Carbon Nitride Heterojunction Photocatalysts for Enhanced Methanol Production from CO2 under Neutral Conditions

Abstract Artificial photosynthesis of alcohols from CO 2 is still unsatisfactory owing to the rapid charge relaxation compared to the sluggish photoreactions and the oxidation of alcohol products. Here, we demonstrate that CO 2 is reduced to methanol with 100 % selectivity using water as the only electron donor on a carbon nitride‐like polymer (FAT) decorated with carbon dots. The quantum efficiency of 5.9 % ( λ =420 nm) is 300 % higher than the previously reported carbon nitride junction. Using transient absorption spectroscopy, we observed that holes in FAT could be extracted by the carbon dots with nearly 75 % efficiency before they become unreactive by trapping. Extraction of holes resulted in a greater density of photoelectrons, indicative of reduced recombination of shorter‐lived reactive electrons. This work offers a strategy to promote photocatalysis by increasing the amount of reactive photogenerated charges via structure engineering and extraction before energy losses by deep trapping.