Thioether-Functionalized 2D Covalent Organic Framework Featuring Specific Affinity to Au for Photocatalytic Hydrogen Production from Seawater

Abstract

Visible light-driven photocatalytic H2 production from seawater faces challenges from the dissolved salts in seawater, which would lead to undesirable decomposition of catalysts and side reactions. Herein, we show a thioether-functionalized covalent organic framework (TTR-COF), which exhibits remarkable photocatalytic H2 production ability from seawater. With the specific affinity of thioether groups for Au ions, TTR-COF shows selectivity in adsorption of Au over other alkaline and alkaline-earth metal cations in seawater, which is critical for uniform loading of Au as a cocatalyst for efficient charge transfer. Besides, the highly conjugated structure containing triazine units in TTR-COF contributes to the visible light harvesting and photoinduced charge generation and separation. The crucial synergistic effects endow TTR-COF with selective coordination to cocatalysts over other cations, as well as superior catalytic stability among other COFs. These suggest that COFs have great potential for photocatalytic H2 production from seawater by taking advantage of their unique structural features.

Integrating single Ni sites into biomimetic networks of covalent organic frameworks for selective photoreduction of CO2

“…[19][20][21][22][23][24] The periodic and permanent porosity endow COFs with a naturemimicking architecture, while the diverse compositions and synthetic approaches allow COFs with tunable microstructures and optical and electronic structures. [25][26][27][28][29] The highly conjugated structure in-plane in COFs can ensure the mobility of photoinduced charges. [30][31][32][33] Moreover, COFs with tunable porosity can accommodate guest molecules for target applications.…”

Rational Design and Application of Covalent Organic Frameworks for Solar Fuel Production

“…The special affinity of Au towards the thioether functional group was studied by functionalizing a COF with a thioether group (TTR-COF), which assisted in the specific adsorption of Au over other alkaline and alkaline-earth metal cations in seawater. This was then used to produce hydrogen under visible light irradiation conditions [ 55 ]. The 2D thioether functionalized COF was synthesized by a condensation of 1,3,5-tris(4-formylphenyl)triazine (TFPT) and 2,5-bis(2-(ethylthio)ethoxy)terephthalohydrazide (BETH) under solvothermal conditions to form TTR-COF.…”

Two‐Dimensional Covalent‐Organic Frameworks for Photocatalysis: The Critical Roles of Building Block and Linkage

“…It can further be used to immobilize gold species as co‐catalyst ( Figure ). [ 82 ] The uniformly distributed gold in TTR‐COF effectively improve its charge transfer efficiency, leading to a hydrogen production rate of 430 μmol g −1 h −1 in the absence of Pt nanoparticles (NPs). Moreover, it can realize the production of hydrogen from seawater with an average hydrogen production rate of 141 μmol g −1 h −1 for 20 h ( λ > 420 nm, TEOA as sacrificial agent), which demonstrates the potential 2D COFs for photocatalytic seawater splitting.…”