Porphyrin-Based Carbon Dots for Efficient Photocatalytic Reduction of CO<sub>2 </sub>to Methanol

Photocatalytic CO 2 reduction to solar fuel is a potential way to overcome the problem of high carbon dioxide concentrations; however, the process still faces enormous challenges, such as the low light absorption efficiency and high carrier recombination rates. This work synthesized tetraphenylporphyrin-based carbon dots (TPP-CDs) for the photocatalytic CO 2 reduction to CH 3 OH under simulated sunlight to extend the absorption region of the CDs. The conduction band of the TPP-CDs has a sufficiently negative reduction potential to reduce CO 2 . TPP-CDs containing 1 wt.% TPP achieved an optimum CH 3 OH production rate of 173.35 μmol·g cat -1 ·h -1 , with a remarkable 2.06-fold increase compared to pristine CDs without TPP. In this study, TPP-CDs were synthesized by changing the CD precursors to improve the utilization of visible light and apply them to the photocatalytic reduction of CO 2 .