Pyrochlore-type La2Zr2O7 was prepared through a sol–gel route and served as a Ru-based catalyst support for ammonia decomposition to produce H2 without COx emission. The NH3 conversion over Ru/La2Zr2O7 could reach 69.5 % at 450 °C under the pure NH3 gas hourly space velocity (GHSV) of 30 000 mL.gcat-1h−1, which is approximately 3.1 times of that over Ru/ZrO2 and 2.2 times of Ru/La2O3 under the same conditions, respectively. It was found that the presence of oxygen vacancies on La2Zr2O7 surface can strongly interact with Ru particles to form the electronic strong metal-support interaction (EMSI), increasing the dispersion of Ru nanoparticles. Additionally, the mobile electrons are effectively transferred from La2Zr2O7 to the surface of Ru particles through the EMSI effect, consequently boosting the recombination desorption of N and ultimately contributing to the exceptional catalytic activity of Ru/La2Zr2O7.