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Efficient Hole Trapping in Carbon Dot/Oxygen‐Modified Carbon Nitride Heterojunction Photocatalysts for Enhanced Methanol Production from CO 2 under Neutral Conditions
Author(s) -
Wang Yiou,
Godin Robert,
Durrant James R.,
Tang Junwang
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202105570
Subject(s) - carbon nitride , carbon fibers , photochemistry , heterojunction , ultrafast laser spectroscopy , chemistry , photocatalysis , methanol , absorption (acoustics) , materials science , nitride , analytical chemistry (journal) , spectroscopy , optoelectronics , nanotechnology , catalysis , organic chemistry , layer (electronics) , quantum mechanics , composite number , composite material , physics
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.