Ultralow-Loading Copper Sulfide Nanosheets on g‑C3N4 as a Visible-Light-Active Photocatalyst for the Regioselective Synthesis of 1,4-Disubstituted 1,2,3-Triazoles

We report for the first time hydrothermally developed copper sulfide–graphitic carbon nitride (Cu1.8S-GCN) nanocomposites as highly efficient photocatalysts for the azide–alkyne cycloaddition (AAC) reaction. Combining GCN with 0.8 wt % (ultralow loading) nanoparticulate Cu1.8S leads to a change in the band structure, resulting in the enhancement of visible-light absorption and thereby mitigating the problems that normally arise from conventional copper-based photocatalytic strategies. The developed strategy provides a sustainable way with high atom economy and easy scalability to furnish 1,4-substituted 1,2,3-triazoles in high yield (up to 99%) with absolute regioselectivity, which outperformed the photocatalysts in recently reported results.