Gold nanocrystal-loaded 2D supramolecular network for plasmon-enhanced nitrogen fixation

Abstract

Light-driven N₂ fixation represents a promising solution to meet the huge demand for ammonia in the chemical industry in the form of energy saving; however, serious bottlenecks in improving the reaction rate and efficiency still exist. Herein, by anchoring gold nanoparticles and nanorods onto a 2D supramolecular network with a polyoxometalate node via electrostatic interaction, plasmon-enhanced photocatalysts were fabricated. Since gold plasmonic components bear absorption to a wide range of light, plasmon-enhanced photocatalysis in the visible and near-infrared regions is achieved. The gold nanorod-loaded single-layer framework turns out to have a higher activity to N₂ fixation under near-infrared photothermal conditions. When the H₅PMo₁₁VO₄₀ cluster is used in the supramolecular framework, the production efficiency of ammonia reaches the highest value ca. 173.8 μmol L⁻¹ h⁻¹ with a turnover frequency of 869.1 mmol M⁻¹ h⁻¹. The catalyst shows catalytic stability under a photothermal environment and more than 85% of the catalytic activity is sustained after 5 cycles.