Sulphur- and nitrogen-codoped layered double hydroxides with expanded interlayer distance for enhanced overall water splitting

Developing highly active, durable, and non-noble electrocatalysts for water-splitting is critical for efficient renewable energy conversion. Nickel-iron layered double-hydroxide (NiFe-LDH) materials show potential in achieving good catalytic performance, however, which was restricted by the scarce active sites and poor conductivity. Herein, we report a series of NiFe-LDH-based materials of expanded interlayer spacing constructed through S/N co-doping with rich active sites, used as a high-efficient bifunctional electrocatalyst for the oxygen and hydrogen evolution reactions (OER and HER). The experimental results indicate that the intercalation/decoration on the interlayer structure of NiFe-LDH can efficiently reduce the energy barrier and accelerate reaction kinetics. Combining with the structural advantages, including the expanded lattice spacing and exposed active surface sites, the resulting S-N/NiFe-LDH anchored in nickel foam (NF) drives an alkaline electrolyzer with a cell voltage of 1.67 V at a current density of 100 mA cm⁻², as well as robust stability over 100 h, which is much superior to the state-of-the-art Pt/C-RuO₂ electrocatalysts.