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

Visible light-driven photocatalytic H-2 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 H-2 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 H-2 production from seawater by taking advantage of their unique structural features.