Selenium-induced NiSe2@CuSe2 hierarchical heterostructure for efficient oxygen evolution reaction.

Electrochemical water splitting is widely studied in the hope of solving environmental deterioration and energy shortage. The design of inexpensive metal catalysts exhibiting desired catalytic performance and durable stability for efficient oxygen evolution is the pursuit of sustainable and clean energy fields. Herein, a three-dimensional (3D) flower-like NiSe2 primary structure, modified with highly dispersed CuSe2 nanoclusters as the secondary structure, is obtained by regulating the growth trend of the nanosheets. Benefiting from the metallicity of selenides and the formation of a heterogeneous interface, NiSe2@CuSe2/NF shows comparable performance toward the oxygen evolution reaction (OER) in an alkaline environment. Upon regulating the synthesis conditions, the catalyst exhibits its optimal performance with ultralow overpotential for the OER when the Ni/Cu molar ratio is 1 : 0.2 and the hydrothermal temperature and hydrothermal time are 200 °C and 6 h, respectively. It provides a current density of 10 mA cm-2 when a potential of 201 mV is applied without iR compensation. In this work, the hierarchical heterostructures of NiSe2 and CuSe2 are synthesized, which exhibit high electrocatalytic activity towards the oxygen evolution reaction and provides a new possibility for the extensive application of copper-based compounds in advanced energy fields.