Figure 4

Schematic diagrams of the structure change of the products (a) Cu@CuS of the first reaction, (b) Cu@CuS-2 of the secondary reaction for 2 h and (c) CuS@Cu9S5-1 of cation exchange with DMF and EG as solvents, respectively.

Schematic diagrams of the structure change of the products (a) Cu@CuS of the first reaction, (b) Cu@CuS-2 of the secondary reaction for 2 h and (c) CuS@Cu9S5-1 of cation exchange with DMF and EG as solvents, respectively.