Xiangcheng Zhang,Jingzhen Zhang,Jie Miao,Xue Wen,Chao Chen,Baoxue Zhou,Mingce Long
Photocatalytic H 2 O 2 production is a promising strategy for decentralized applications, but to realize efficient H 2 O 2 production in the ambient conditions and absence of organic sacrifice remains challengeable. Herein, anthraquinone functionalized covalent organic frameworks (TpAQ-COFs) were fabricated by β-ketoenamines links of 2,6-diaminoanthraquinone (AQ) and 2, 4, 6-triformylphloroglucinol (Tp), and the structures and compositions were tuned by controlling the condensation time. The increase of time favors the assembly of TpAQ-COFs into more ordered lamellar stacking structure, and induces the increase of enol-imine form. The critical role of anthraquinone moieties as the active sites for oxygen reduction was proved, that is, facilitating charge separation and enhancing the activity and selectivity of H 2 O 2 production. Upon visible light irradiation, the TpAQ-COF synthesized after 12 h reaction has the highest content of anthraquinone moieties and the best performance for H 2 O 2 production (420 μmol h −1 g −1 ) in the absence of organic sacrificial agents. These findings bring insights to incorporate anthraquinone chemistry into photocatalysts at molecular levels for efficient H 2 O 2 production.
Two-dimension covalent organic frameworks (2D COFs) are porous materials with the interlayer π-π interaction and excellent optoelectronic properties. Their adjustable porous structure and designable molecular structure endow them unlimited possibilities in the field of optoelectronic materials and other functional materials . In this paper, 2D COF electrochromic films were prepared by solvothermal synthesis method with different amounts of functionalized carbon nanotubes (FCNT) loading to improve their conductivity. The morphology characterization of COF DAAQ-TFP reveals its intertwined nanofiber structure. The electrochromic performance of COF DAAQ-TFP film shows that the color of COF DAAQ-TFP and FCNT-COF DAAQ-TFP have a reversible transformation from orange to dark brown during the redox process . When the loading amount of FCNT is 1%, FCNT-COF DAAQ-TFP exhibits best electrochromic properties, which has a contrast of 0.358 and coloring time of 5.7 s. Relative to COFs, FCNT-COF has enhanced contrast and stability, which is a potential electrochromic material in many fields such as smart window and smartphone back case.