Cu2SnS3 nanocrystals decorated rGO nanosheets towards efficient and stable hydrogen evolution reaction in both acid and alkaline solutions

Abstract Copper-containing bimetallic sulfides are regarded as an emerging low-cost catalyst for electrocatalytic hydrogen generation. In this work, we report for the first time the ternary Cu2SnS3 (CTS) nanocrystals anchored reduced graphene oxide (rGO) nanosheets (CTS@rGO) as a superior electrocatalyst for efficient hydrogen generation. The CTS nanocrystals with 5–10 nm are much homogeneously distributed on the surface of rGO nanosheets. In the CTS@rGO composite, the rGO works as a robust scaffold that can effectively suppress aggregation of the CTS nanocrystals and ensure more exposed active sites on CTS surfaces. Furthermore, the conductive rGO is beneficial to fast charge transfer. Therefore, the CTS@rGO catalyst possesses a large electrocatalytic active surface area and a small charge transfer resistance. As a result, the CTS@rGO exhibits significantly enhanced catalytic activity for hydrogen evolution reaction (HER) in both the acid and alkaline electrolytes in comparison with the pristine CTS nanocrystals. The CTS@rGO delivers a striking catalytic kinetic metrics of a small Tafel slope of 54 mV dec−1, a low overpotential of 252 mV at a current density of 10 mA cm−2, long operation stability of 4 day in the acid electrolyte.