Antiferroelectric SnO₂ Network with Amorphous Surface for Electrochemical N₂ Fixation

Abstract

Electrochemical nitrogen fixation-a sustainable pathway for converting abundant N₂ into NH₃ using renewable energy-holds transformative potential for revolutionizing artificial nitrogen cycles. Nevertheless, even the state-of-the-art catalytic systems also suffer from inadequate N₂ adsorption capacity, which critically limits ammonia production rates and Faradaic efficiency (FE). To overcome this bottleneck, we strategically leveraged the antiferroelectric properties of SnO₂ to establish dipole-dipole interactions with N₂ molecules, synergistically enhancing both N₂ adsorption and activation kinetics. Building on this foundation, we construct a three-dimensional (3D) porous SnO₂ network with unsaturated amorphous surfaces. Both experiment and first-principles calculations indicate that all the exposed antiferroelectric surfaces could effectively adsorb N₂, enhancing the N₂ adsorption ability and maximizing active sites accessibility. The optimized catalyst delivers exceptional performance, achieving an NH₃ production rate of 57.38 µg h^-1mg^-1 _cat and a FE of 33.26%, representing one of the highest reported values among aqueous-phase ammonia synthesis catalysts. These breakthroughs not only establish a universal design framework for gas-involving electrocatalysts but also pioneer an integrated strategy to elevate nitrogen utilization efficiency in next-generation sustainable energy infrastructures.