Laser-direct-writing of 3D self-supported NiS2/MoS2 heterostructures as an efficient electrocatalyst for hydrogen evolution reaction in alkaline and neutral electrolytes

Searching for low-cost widely applicable electrocatalysts for hydrogen production is very important. Here, 3D self-supported NiS2/MoS2 heterostructures were synthesized via a one-step millisecond-laser-direct-writing method; these structures exhibited excellent hydrogen evolution reaction activities over a wide pH range. The current density of 10 mA cm−2 could be reached at low overpotentials of 98 and 159 mV in alkaline and neutral electrolytes, respectively. Such an outstanding electrocatalytic performance should be attributed to the integration of the 3D self-supported nanostructures, the high conductivity of the framework, and particularly, the incalculable heterointerfaces formed between NiS2 and MoS2. This work provides a new strategy to study interfacial engineering and the mechanism of interface enhancement.