Boosting photocatalytic Cr(VI) reduction activities of layered COF through regulating donor-acceptor units and the orientation of imine bonds

A novel covalent organic framework for efficient photocatalytic reduction of Cr(vi) and synergistic removal of organic pollutants under visible light irradiation

“…Furthermore, IPA acted as an ·OH scavenger and blocked the oxidation of Cr( iii ) on the HDU-26 surface, preventing its conversion to Cr( vi ). 36,54 In contrast, the reduction rate of Cr( vi ) decreased significantly after adding Na 2 S 2 O 8 , and it was only 29% after 60 min of reaction. The reduction rate of Cr( vi ) was decreased by the addition of BQ.…”

“…Previous studies have shown that the π-conjugated structural units in D-A type COFs play a crucial role in light trapping. 18,35,36 Our conjugated structure had thiophene in BTT as the electron-donor unit and benzothiadiazole in BT as the electron-absorbing unit, and this structure promoted the spatial segregation of charge carriers, thus attenuating charge complexation and giving HDU-26 excellent photocatalytic performance. Consequently, the photocatalytic active sites are assumed to be mainly located on the thiophene and benzothiadiazole units.…”

Enhancement of Mass Transfer Process for Photocatalytic Reduction in Cr(VI) by Electric Field Assistance

“…When any of the factors of TA, light, catalyst or electricity are absent, the catalytic effect is greatly reduced. Due to the synergistic effect of CDI and photocatalysis with TA attached, this PCS process exhibits a robust Cr(VI) photoreduction capability, which is superior to most of the current POPs-based photocatalysts ( Table S5 [ 21 , 46 , 47 , 48 , 49 , 50 ]). For 10 ppm Cr(VI), 100% removal can be achieved in 60 min.…”

“…Therefore, how to improve the photoreduction ability of materials for Cr(VI) has become a hot topic [ 20 ]. On the one hand, the visible light utilization and free radical generation of the photocatalysts can be enhanced by molecular design [ 21 , 22 ], structural modulation [ 23 ], and heterogeneous structures [ 24 , 25 ]. On the other hand, the mass transfer process can also be enhanced to improve the photocatalytic performance.…”

Embedding Au nanoclusters into the pores of carboxylated COF for the efficient photocatalytic production of hydrogen peroxide

“…33,34 Gong et al loaded Au NPs onto the backbone of covalent organic frameworks (COFs) synthesized at room temperature and these composites exhibited excellent photocatalytic reduction activity for Cr(VI). 35 Zhang et al immobilized Pt or Pd nanoparticles (1.7 ± 0.2 nm) in the pores of COF and they showed excellent catalytic activity for nitrophenol reduction and Suzuki-Miyaura coupling reactions under mild conditions. 36 Wei and co-workers integrated plasmonic Au NCs into a single COF particle via a synchronized assembly/interfacial polymerization method to form Au/COF hybrids, which exhibited excellent photocatalytic degradation of organic pollutants in water.…”