Both COFs catalysts were synthesized by simple stirring, and the synthesis process was as shown in Scheme 2. Melamine was used as a monomer to react with piperazine-1,4-dicarbaldehyde or terephthalaldehyde in DMSO to obtain MelCOF-1 or MelCOF-2. Then the metal ions were introduced into the COFs by the strong coordination interaction between the metal ions and the N in the substrate of the COFs, and the Rh/MelCOF-1 or Rh/MelCOF-2 was obtained. Rh/MelCOF-1 were 357m 2 g -1 and 239m 2 g -1 respectively. The BET surface areas of MelCOF-2 and Rh/MelCOF-2 were 457 m 2 g -1 and 284 m 2 g -1 , respectively. In addition, according to the Barrett-Joyner-Halenda (BJH) method, the load Rh reduces the Vpore of MelCOF-1 and MelCOF-2 from 0.339 cm 3 and 0.827 cm 3 to 0.289 cm 3 and 0.592 cm 3 , respectively. The reduction of specific surface areas and pore volume can be attributed to the successful encapsulation of ionic rhodium in MelCOF channels after the introduction of Rh. The relatively narrow pore size distribution of Rh/MelCOF-1 and Rh/MelCOF-2 is concentrated between 1.5 nm-5.7 nm, and the pore size changes slightly compared with the carrier MelCOF, indicating that the existence of Rh does not block the cavity channel of Rh/MelCOF. In addition, the Rh/MelCOF-1 and Rh/MelCOF-2 supported by MelCOF materials are further analyzed by EDS. As shown in Figure , there exist S elements in addition to C and N of synthetic COF materials. Although a variety of solvents are used to wash the COF material carrier in the synthesis process, and Soxhlet extraction is used in the process of loading Rh, there is still a small amount of DMSO unwashed, so some S elements is detected. At the same time, the Rh element was also observed. It can be seen that Rh was uniformly loaded into MelCOF, but the content of Rh (1.32Wt%) in Rh/MelCOF-1 was significantly lower than that in Rh/MelCOF-2 (5.86Wt%). Rh3d5/2 (Rh-Nx) energy levels belonging to Rh (III) species. At the same time, the 305.9 eV satellite peak of Rh is also observed. There is also a corresponding peak in Rh/MelCOF-2. In addition, compared with Rh/MelCOF-1, the Rh/MelCOF-2 has more signal peaks of 317.0 eV and 312.1eV, which is attributed to the peak of rhodium chloride that is not strongly coordinated with N in the COF ligand. Thus it can be seen that the Rh species mainly exist in the form of Rh-NX in Rh/MelCOF-1, while in the Rh/MelCOF-2 catalyst, in addition to Rh-NX, there is rhodium chloride that filled in the MelCOF2 channel. Therefore, although the amount of rhodium chloride used in the synthesis process of the two COF catalysts is the same, the content of Rh on the actual load MelCOF-2 is higher than that of MelCOF-1, which also confirms the results of EDS characterization. The binding energy of rhodium chloride decreases from 317.0 eV and 312.1 eV energy to 314.6 eV and 309.7 eV respectively, which indicates the electron transfer from N to Rh and reveals the strong metal-carrier interaction between Rh and MelCOF.