Triazine-Based Covalent Organic Framework for Photocatalytic Water Oxidation: The Role of Bipyridine Ligand and Cobalt Coordination

Covalent organic frameworks (COFs) are crystalline porousconjugatedpolymers that have been widely used for photocatalytic hydrogen evolutionand CO2 reduction. However, only few COFs showed photocatalyticoxygen evolution, which is a more challenging half-reaction of photocatalyticwater splitting. Here, we presented visible-light-driven photocatalyticwater oxidation of a triazine-based COF (TAPT-Bpy-COF) coordinatedwith cobalt as cocatalysts. The highest oxygen evolution rate (OER)was achieved at 483 & mu;mol g(-1) h(-1) (& GE;420 nm) with an efficient apparent quantum efficiency (AQE)of 7.6% (420 & PLUSMN; 20 nm). The highly photocatalytic oxygen evolutionactivity of TAPT-Bpy-COF could be attributed to its highly orderedstructures, high surface area, good wettability as well as enhancedcharge separation. This work demonstrates the potential of COFs forphotocatalytic oxygen evolution half-reaction and overall water splitting.