本文要点：
由H2O和O2光催化合成H2O2被认为是最有前途的制备H2O2的替代方法之一。开发高活性、高选择性的光催化剂对实现高效的H2O2光合作用具有重要意义。
本文通过缺电子单元4,4′,4″-（1,3,5-苯三基-2,1-乙二基）三苯胺与富电子单元苯并[1,2-b:3,4-b′：5,6-b″]三噻吩-2,5,8-三羧醛之间的缩合反应制备了乙炔基连接的供体-受体共价有机骨架，命名为EBBT-COF。
粉末X射线衍射和N2吸附等温线揭示了EBBT-COF的结晶多孔hcb网络，孔中心尺寸约为2.3 nm。光谱表征表明，由于其供体-受体结构，EBBT-COF具有优异的可见光吸收能力和增强的光诱导电荷分离和传输效率。
密度泛函理论计算和电化学测试表明，EBBT-COF对三乙炔基苯和三噻吩的2e- O2还原反应和2e-水氧化反应具有较高的活性和选择性，分别加速了O2到H2O2和H2O到H2O2的转化。
这些优点使EBBT-COF成为一种很有前途的光催化剂，可以从H2O和O2中生成H2O2， H2O2产率为5686 µmol g−1 h−1，最佳表观量子产率为15.14%，光化学转换效率为1.17% (λ > 400 nm)，是目前报道的性能最好的COF基光催化剂之一。
Figure 1. a) The synthesis of EBBT-COF and PBBT-COF. The simulated AA stacking of b,c) EBBT-COF and d,e) PBBT-COF. f) PXRD, g) N2 sorption isotherms, h) SEM image, and i) HR-TEM image of EBBT-COF. j) PXRD, k) N2 sorption isotherms, l) SEM image, and m) HR-TEM image of PBBT-COF.
Figure 2. a) UV–vis DRS spectra of EBBT-COF and PBBT-COF. b) Tauc plots of EBBT-COF and PBBT-COF. c) Bandgap structure diagram of EBBT-COF and PBBT-COF. d) Transient photocurrents of EBBT-COF and PBBT-COF. e)H2O2 yield of EBBT-COF and PBBT-COF. f) AQY of EBBT-COF. g) Comparison of SCC efficiency and H2O2 yield for EBBT-COF with COF-based photocatalysts reported thus far. h) H2O2 yield of EBBT-COF and PBBT-COF in the five successive cycles of photocatalytic reactions.
Figure 3. a) The ORR polarization curves and Koutecky–Levich plots obtained by RDE measurements. b) RRED measurements of EBBT-COF and PBBTCOF. c) H2O2 selectivity and n of EBBT-COF and PBBT-COF. WOR polarization curves with a potential of d) +0.60 V versus Ag/AgCl and e) −0.23 V versus Ag/AgCl applied on Pt ring electrode. f) EPR trapping experiments for ·O2− on EBBT-COF and PBBT-COF by DMPO in the dark and illumination for 10 min. g) Photocatalytic yield of ROS for EBBT-COF and PBBT-COF. h) In situ DRIFTS spectra for the photocatalytic system of EBBT-COF.
Figure 4. a) The materials/electrons flowing pathway according to theoretical calculation. The numbers in circles are corresponding to the reaction Equations in the text (i.e., ① means Equation (1)) b) Gibbs free energy evolution during the reaction process. c) The 𝜋-linking strength of the bond between the central and peripheral benzene rings in EBBT-COF and PBBT-COF.
https://doi.org/10.1002/aenm.202404497
