Constructing superhydrophilic CoRu-LDH/PANI nanowires with optimized electronic structure for hydrogen evolution reaction

Abstract

Promoting the dissociation of water and desorption of hydrogen are both crucial challenges for improving the hydrogen evolution reaction (HER) activity and stability in alkaline media, especially at large current densities. Herein, we demonstrate a polyaniline-coated CoRu-LDH (CoRu-LDH/PANI) nanowire array electrocatalyst for efficient and stable alkaline HER. Benefiting from the optimized electronic structure and surface properties, the as-prepared CoRu-LDH/PANI shows an excellent HER activity with low overpotentials of 250, and 275 mV, respectively, at large current densities of 500 and 1000 mA cm−2 in 1.0 M KOH, superior to the benchmark 20% Pt/C and the pristine CoRu-LDH. Furthermore, CoRu-LDH/PANI exhibits an unprecedented stability at a large current density of 500 mA cm−2 even after 50 h. The combined experimental and density functional theory (DFT) investigations reveal that PANI coating not only performs as an electronic regulator to lift the valence states and reduces the binding strength to hydrogen intermediates, leading to the superior HER performance, but also affords a superhydrophilic surface to promote the rapid transport of electrolytes and bubbles, which is crucial for the long-term stability at large current density. This work provides an effective guidance for engineering efficient alkaline HER eletrocatalysts towards practical water electrolysis.