Layered-Double-Hydroxide Nanosheets as Efficient Visible-Light-Driven Photocatalysts for Dinitrogen Fixation

Abstract

Semiconductor photocatalysis attracts widespread interest in water splitting, CO₂ reduction, and N₂ fixation. N₂ reduction to NH₃ is essential to the chemical industry and to the Earth's nitrogen cycle. Industrially, NH₃ is synthesized by the Haber–Bosch process under extreme conditions (400–500 °C, 200–250 bar), stimulating research into the development of sustainable technologies for NH₃ production. Herein, this study demonstrates that ultrathin layered-double-hydroxide (LDH) photocatalysts, in particular CuCr-LDH nanosheets, possess remarkable photocatalytic activity for the photoreduction of N₂ to NH₃ in water at 25 °C under visible-light irradiation. The excellent activity can be attributed to the severely distorted structure and compressive strain in the LDH nanosheets, which significantly enhances N₂ chemisorption and thereby promotes NH₃ formation.

Layered-double-hydroxide (LDH) nanosheets are shown to exhibit outstanding visible-light-driven photocatalytic activity for the reduction of N₂ to NH₃ under ambient conditions. Irradiation of CuCr-LDH nanosheets in N₂-saturated water with 500 nm monochromatic light produces NH₃. The excellent activity can be attributed to the severely distorted structure and compressive strain of the LDH nanosheets, promoting NH₃ formation.

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