Defects engineering and interface regulation on nickel-rich sulphides promoting water/urea/ethanol electrooxidation.

• The CeS 2 incorporation modulates the internal electronic state. • Ce species stabilizes some of the surface sulphide against self-oxidation during OER process. • The strategy of iron dopant is conducive to induce plentiful S-defects. • The nanoparticles-rich structure affords ample holes and irregular flow channels. • Polyvalent Ce species provides great redox property, enhancing the electrocatalytic activity. Design and fabrication of high-efficiency nickel-rich electrocatalytic materials for sluggish oxygen evolution reaction (OER) remains a tremendous challenge. Modulating internal electronic state and accelerating charge transfer are two of vital means to optimizing electrocatalysts. In this work, nanoparticles-rich Fe-(CeS 2 /Ni 3 S 2) hybrid material with abundant heterointerfaces and sulfur-defects are facilely synthesized. The strategy of iron dopant is conducive to induce more sulfur defects. The cerium species can modulate the internal electronic state and stabilize some of the surface sulphide against self-oxidation during OER process. This self-supported heterogeneous material requires overpotentials of 254 and 372 mV to reach the current densities of 100 and 500 mA cm−2 in alkaline condition. The addition of urea or ethanol to the bath solution has been demonstrated as an efficient strategy for reducing the onset potential and decreasing energy consumption, thereby confirming the feasibility of applying this approach to energy-saving hydrogen production through electrolysis wastewater splitting. [ABSTRACT FROM AUTHOR]