Piezo‐Photocatalytic Synergy in BiFeO₃@COF Z‐Scheme Heterostructures for High‐Efficiency Overall Water Splitting

Abstract

Solar-driven overall water splitting is an ideal way to generate renewable energy while still challenging. For the first time, this work combined covalent organic frameworks (COFs) and piezoelectric material by covalent linkages to form Z-scheme core@shell heterostructure for overall water splitting. Benefiting from the synergistic effect between the polarized electric field and photo-generated charges, as well as the precise adjustment of shell thickness, the carrier separation and utilization efficiency is greatly improved. The optimal BiFeO 3 @TpPa-1-COF photocatalyst revealed hydrogen (H 2 ) and oxygen (O 2 ) production rates of 1416.4 and 708.2 μmol h À 1 g À 1 under the excitation of ultrasonication coupled with light irradiation, which is the best performance among various piezo-and COF-based photocatalysts. This provides a new sight for the practical application of highly efficient photocatalytic overall water splitting.

Overall Utilization of Photoexcited Charges for Simultaneous Photocatalytic Redox Reactions

“…Nevertheless, owing to the complex electron transfer steps and high energy barrier. The poor H2 evolution performance and apparent quantum efficiency (AQE) lead to hard implications of photocatalytic OWS (Table 1) [118][119][120][121][122][123][124][125][126][127][128][129][130][131][132][133][134][135][136][137] .…”

Recent advances in metal-free covalent organic frameworks for photocatalytic applications in energy and environmental fields

“…19,20 In particular, COFbased electrocatalysts have achieved considerable advances in the water cycle, [21][22][23] the carbon energy cycle, [24][25][26] and supercapacitors; 27,28 the developments of these energy storage and conversion applications have been discussed in detail in some very excellent review articles. 29,30 Since the discovery of heterogeneous photocatalysis over semiconducting COFs by Jiang and co-workers, 31 COF-based materials have been widely used in diverse photocatalytic elds, such as water splitting, 32,33 CO 2 reduction, 34,35 organic synthesis 36,37 and environmental remediation. [38][39][40] COF-based photocatalysts have several advantages compared to other inorganic photocatalysts: (i) the dened structure-property relationship in COFs is favourable for modication; (ii) COFs have higher specic surface areas, resulting in hundreds or even thousands of active sites; (iii) COFs have good crystallinity, which ensures their stability and signicantly reduces the electron-hole recombination frequency; (iv) the periodically ordered columnar array of the p-p-conjugated system facilitates electron delocalisation and endows COFs with excellent electron transport properties and photoconductivity; and (v) the designability of the donor-acceptor structure and introduction of suitable building blocks facilitate electron-hole separation and enhance the photocatalytic performance of COFs.…”

Eu3+-Functionalized Nanoporous Covalent Organic Frameworks for Fluorescence Detection and Removal of Tetracycline

“…Covalent organic frameworks (COFs) are a kind of important crystalline organic porous polymers that have attracted extensive interest in versatile fields such as electricity storage, , gas storage, , photocatalysis, , electrocatalysis, , light-emitting devices, electrochemical sensors, , fluorescent sensors, − and so on due to their high specific surface area, modifiable pore channels, and designable functionality. As reported, most crystalline COFs are constructed by thermodynamic reversible organic reactions, but the obtained products show unsatisfied stability in many chemical environments, such as corrosive or moist systems .…”