Melamine (500mg) and piperazine-1,4-dicarbaldehyde (1139mg) were added to 60 ml DMSO at a molar ratio of 2:3 and ultrasonic until the precursor was completely dissolved. Then nitrogen protective condensation refluxed was carried out at 180 °C for 72 hours. Then the white sediment was collected and washed with ethanol, acetone, tetrahydrofuran, and dichloromethane respectively. Finally, vacuum drying at 90 °C for 8 h, and expressed as MelCOF-1. For comparison, MelCOF-2 was synthesized using melamine (500mg) and terephthalaldehyde (1074mg) at the same molar ratio of 2:3 and the same method. To prepare Rh-anchored COF, the RhCl3 methanol solution is introduced into the pre-synthesized COF with a metal content of 5wt% and stirred at room temperature for 24 hours. After the reaction, the excess unloaded RhCl3 was removed by Soxhlet extraction, and then dried in a vacuum at 80 °C for 12 h.