Synthesis of Pore‐Wall‐Modified Stable COF/TiO₂ Heterostructures via Site‐Specific Nucleation for an Enhanced Photoreduction of Carbon Dioxide

Abstract

Constructing stable heterostructures with appropriate active site architectures in covalent organic frameworks (COFs) can improve the active site accessibility and facilitate charge transfer, thereby increasing the catalytic efficiency. Herein, a pore‐wall modification strategy is proposed to achieve regularly arranged TiO2 nanodots (≈1.82 nm) in the pores of COFs via site‐specific nucleation. The site‐specific nucleation strategy stabilizes the TiO2 nanodots as well as enables the controlled growth of TiO2 throughout the COFs’ matrix. In a typical process, the pore wall is modified and site‐specific nucleation is induced between the metal precursors and the organic walls of the COFs through a careful ligand selection, and the strongly bonded metal precursors drive the confined growth of ultrasmall TiO2 nanodots during the subsequent hydrolysis. This will result in remarkably improved surface reactions, owing to the superior catalytic activity of TiO2 nanodots functionalized to COFs through strong NTiO bonds. Furthermore, density functional theory studies reveal that pore‐wall modification is beneficial for inducing strong interactions between the COF and TiO2 and results in a large energy transfer via the NTiO bonds. This work highlights the feasibility of developing stable COF and metal oxide based heterostructures via organic wall modifications to produce carbon fuels by artificial photosynthesis.

Boosting Photocatalytic CO2 Reduction with H2O by Oxygen Vacancy- and Hydroxyl-Tailored SrBi2Ta2O9 Surface-Frustrated Lewis Pairs

“…The E VB‑NHE values of SBT and V O -SBT-OH were calculated to be 2.26 and 2.24 V, respectively, according to eq as follows: E VB − NHE = φ + E VB − VAC − 4.44 where the E VB‑NHE is E VB vs normal hydrogen electrode and the φ is the instrument work function with a value of 4.50 eV. The conduction band potential versus normal hydrogen electrode ( E CB‑NHE ) was calculated through eq E CB − NHE = E VB − NHE − E g Therefore, the E CB‑NHE values of SBT and V O -SBT-OH are calculated to be −0.70 and −0.68 V, respectively (the inset of Figure b).…”

Covalent Organic Frameworks Meet Titanium Oxide

“…The abundant (N^N) sites in the COF can anchor the TiO 2 within the pores, forming pore-wall-modified COF/TiO 2 heterostructures. 131 Zhang and co-workers synthesized TpTa-COF using Tp and Ta as building blocks. Then, the prepared TpTa-COF, TBT, and Fe(NO 3 ) 3 •9H 2 O were mixed to prepare Fe-TiO 2 @COFs by the solvothermal method.…”

Combination of covalent organic frameworks (COFs) and polyoxometalates (POMs): the preparation strategy and potential application of COF–POM hybrids

“…26,27 In recent studies, scientists have thoroughly investigated the topological semimetal and higher-order topological insulator properties of COFs through quantum chemical calculations, which are important for a deeper understanding of COFs and for the design and development of their properties. 28–30 In order to expand the usage of COFs and improve their performance, they are also mixed with other materials, such as graphene, 31 carbon nanotubes, 32 metal oxides, 33 metal nanoparticles, 34 conductive polymers, 35 MOFs (metal–organic frameworks), 36 MXenes 37 and so on. Recently, POMs were introduced into COFs to construct COF–POM hybrids.…”