Highly Crystalline Pd₁₃Cu₃S₇ Nanoplates Prepared via Partial Cation Exchange of Cu_1.81S Templates as an Efficient Electrocatalyst for the Hydrogen Evolution Reaction

Chemical transformations via postsynthetic modification of colloidal nanocrystals have received great attention as a rational synthetic route to unprecedented nanostructures. In particular, the cation exchange reaction is considered as an effective method to alter the composition of the starting nanostructures while maintaining the initial structural characteristics. Herein, we report the synthesis of highly crystalline Pd₁₃Cu₃S₇ nanoplates (NPs) via partial cation exchange of the Cu_1.81S phase by Pd cations, with Cu_1.94S NPs and Pd₁₃Cu₃S₇/Cu_2-xS janus heterostructure as the intermediate phases. The highly crystalline Pd₁₃Cu₃S₇ ternary NPs exhibit excellent electrocatalytic performance toward the hydrogen evolution reaction (HER) under acidic conditions. The HER activity of Pd₁₃Cu₃S₇ NPs with its overpotential as low as 64 mV at -10 mA cm^-2 is superior to those of amorphous PdCuS and commercial Pd/C catalysts, demonstrating the importance of nanocrystal crystallinity in boosting the HER activity. They also exhibit excellent stability as compared to commercial Pt/C and Pd/C under strongly acidic conditions.