Strain-Engineered Ru-NiCr LDH Nanosheets Boosting Alkaline Hydrogen Evolution Reaction

Ruthenium (Ru) has been considered as a promising candidate for alkaline hydrogen evolution reaction (HER); however, the hydrogen adsorption on Ru needs to be optimized to enhance the electrocatalytic activity. Strain engineering is an effective method to regulate the hydrogen adsorption, while the systematic study of the strain effect over hydrogen adsorption of Ru remains a challenge. Herein, Ru-incorporated nickel–chromium-layered double hydroxide (LDH) nanosheets with different levels of compressive strain are constructed to tune the hydrogen adsorption. The strain-engineered Ru-NiCr LDH exhibits a low overpotential of 30 mV at 100 mA cm–2 and good stability over 10,000 potential cycles for HER. When the cathode catalysts are assembled in an anion exchange membrane water electrolyzer (AEMWE), the cell delivers high current densities of 640 and 1940 mA cm–2 at 1.8 V when fed with pure water and 1 M KOH solution, respectively. The enhanced electrocatalytic performance of Ru-NiCr LDH is attributed to the weakened hydrogen adsorption caused by a downshift of the d-band center, which is induced by the strain effect. This work demonstrates the effectiveness of strain engineering in designing active catalysts for hydrogen production.