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

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.