Morphological and structural engineering in amorphous Cu₂MoS₄ nanocages for remarkable electrocatalytic hydrogen evolution

Morphological and structural control of amorphous nanomaterials is challenging due to the long-range disordered atomic arrangements. Herein, we firstly propose a controllable self-hydrolyzing etching-precipitating (SHEP) method to fabricate the regular-shaped amorphous Cu₂MoS₄ nanocages (a-Cu₂MoS₄ NCs) with hollow porous structures under ambient conditions. Benefitting from the hollow porous structures and the amorphous characteristics with copious sulfur vacancies, the a-Cu₂MoS₄ NCs possess more enhanced activity toward hydrogen evolution reaction (HER) than their crystalline counterparts. The octahedral a-Cu₂MoS₄ NCs with a shell thickness of 20 nm, which balance the appropriate surface porosity and good structural stability, exhibit the best HER activity with a low overpotential of 96 mV at 10 mA cm⁻² and a small tafel slope of 61 mV decade⁻¹ in alkaline environment. Moreover, this method is very versatile and can be extended to synthesize other ternary nanocages. Our current work may shed light on the precise controllable synthesis of various ternary nanocages and open a new frontier for developing highly active amorphous catalysts.