Using transition metal-based deep eutectic solvents to synthesize transition metal-doped carbon nitrides for photo-Fenton degradation of organic dyes and antibiotics

Transition metal doped g-C₃N₄ composites have been proved as promising photo-Fenton catalysts for degrading organic pollutants. The efficient coordination between transition metal ions and nitrogen atoms is crucial to the preparation of transition metal doped g-C₃N₄ composites. However, it is a challenge to ensure the high coordination efficiency of transition metal ions in g-C₃N₄. In this work, two series of monometallic doped Co_x-g-C₃N₄ and bimetallic doped Co_1.2Fe_y-g-C₃N₄ composites were synthesized by employing two transition metal-based deep eutectic solvents (DESs) as reaction media. The mild ionothermal conditions provided a favorable environment for doping transition metal ions in g-C₃N₄. After annealing these composites, the as-formed Co_x-CN and Co_1.2Fe_y-CN composites displayed excellent photo-Fenton activities for degrading organic dyes and antibiotics. Moreover, compared with Co_x-CN, Co_1.2Fe_y-CN exhibited enhanced photo-Fenton activities. This research might offer a new approach for preparing transition metal doped g-C₃N₄ composites in DESs.