Engineering of Single Atomic Cu-N<sub>3</sub> Active Sites for Efficient Singlet Oxygen Production in Photocatalysis
Laiyu Luo, Xudong Xiao, Qi Li, Siyu Wang, Yuxin Li, Jungang Hou, Baojiang Jiang
Abstract
Photocatalytic generation of singlet oxygen (1O2) is an attractive strategy to convert organic chemicals to high value-added products. However, the scarcity of suitable active sites in photocatalysts commonly leads to the poor adsorption and activation of oxygen molecules from a triplet state to a singlet state. Here, we report single atomic Cu-N3 sites on tubular g-C3N4 for the production of singlet oxygen. X-ray absorption fine spectroscopy, in combination with high-resolution electron microscopy techniques, determines the existence of atomically dispersed Cu sites with Cu-N3 coordination mode. The combined analysis of electron spin resonance and time-resolved optical spectra confirmed that a single atomic Cu-N3 structure facilitates a high concentration of 1O2 generation due to charge transport, electron–hole interaction, and exciton effect. Benefiting from the merits, a single atomic photocatalyst yields nearly 100% conversion and selectivity from thioanisole to sulfoxide within 2.5 h under visible light irradiation. This work deeply reveals the design and construction of catalysts with specific active sites, which are helpful to improve the activation efficiency of oxygen.