A Universal Synthesis Strategy for Lanthanide Sulfide Nanocrystals with Efficient Photocatalytic Hydrogen Production

Abstract As an important lanthanide (Ln)‐based functional materials, the Ln chalcogenides possess unique properties and various applications. However, the controllable synthesis of Ln chalcogenide nanocrystals still faces great challenges because of the rather poor affinity between Ln and chalcogenide ions (S, Se, Te) as well as strong preference of combination with existed oxygen. Herein, a facile but general heterogeneous nucleation synthetic strategy is established toward a series of colloidal ternary Cu Ln sulfides nanocrystals using the Ln dithiocarbamates and CuI as precursors. To extend this synthetic protocol, similar strategy is used to prepare six kinds of high quality CuLnS 2 nanocrystals, while the bulk ones are only obtained by the traditional solid‐state reaction at rigorous condition. Importantly, high‐entropy nanocrystals CuLnS 2 and CuEu x Ln 2‐x S 3 which contain six Ln elements (Nd, Sm, Gd, Tb, Dy) are readily obtained by the co‐decomposed process attributed to their similar diffusion speed. As a proof‐of‐concept application, CuEu 2 S 3 nanocrystals showed efficient photocatalytic hydrogen production properties.