Integrating CoNiSe2 Nanorod-arrays onto N-doped Sea-sponge-C spheres for highly efficient electrocatalysis of hydrogen evolution reaction

A key issue for enhancing performance of hydrogen evolution reaction (HER) by utilizing seawater for sustainable clean energy is to develop a highly efficient, stable and economical electrocatalyst. Herein, a uniquely hierarchical nanostructure of CoNiSe2 nanorod-arrays (NRAs) integrated onto N-doped sea-sponge-carbon spheres (CoNiSe2/N-SSCSs) was designed and synthesized using successive ultrasonic spray pyrolysis (USP) and solvothermal - hydrothermal selenization (SHS) processes. Attributed to intrinsic HER activity of CoNiSe2 NRAs together with effective electron-transfer and ion-diffusion pathways of N-SSCSs, the CoNiSe2/N-SSCSs nanocomposites exhibited highly stable HER electrocatalytic performances in both alkaline electrolytes and alkaline simulated seawater. The required overpotential is as low as 88 mV with a Tafel slope of 83 mV dec−1 at 10 mA cm−2 in 1.0 M KOH, which are comparable to the electrode of commercial Pt/C (η10 = 35 mV & b = 58 mV dec−1).