CuS–Cu9S8 nanoparticles as an efficient catalyst: A facile method via anion controlled

In this paper, a facile, surfactant-free and mild solution chemistry route was employed to prepare copper sulfide (CuS–Cu 9 S 8 ) nanoparticles (NPs) by using anion-controlled agents with a different electronegativity. Counterions CH 3 COO − were found to be suitable for regular hexagonal morphology formation, whereas in the presence of NO − 3 ${\text{NO}}_3^{-}$ , irregular structure is obtained. By changing the anion of the copper precursor, the ratio of formation of Cu 9 S 8 and CuS can be changed, and the band gap energy ( Eg ) of as-prepared NPs can be controlled in the presence of anion-controlled agents. Moreover, we demonstrate here the catalytic performance of the as-prepared samples for the degradation of methylene blue (MB) both under the simulated natural light and in dark, and the result shows that the CuS–Cu 9 S 8 NPs exhibited better catalytic activity under visible light ( > 5 0 $>50$ %) than in darkness (45%), and CuS–Cu 9 S 8 NPs with higher electronegativity of anion-controlled exhibited the higher catalytic performance. In addition, a simple and direct diagram was applied to illustrate the mechanism of the degradation of MB.