Coal-based SiO₂/GO nanosheets were prepared by modified Hummers method using Xinjiang Wucaiwan coal as raw materials. According the characterization tests results, graphite-like crystal structures had formed. Meanwhile, the Si elements presented in coal could form SiO₂ particles during the oxidation process and loaded onto the GO surface in situ to produce structurally stable coal-based SiO₂/GO sheets which is quite advantageous as carrier. Ag nanoparticles prepared by thermal reduction was loaded on the surface of coal-based SiO₂/GO. The structure of Ag/SiO₂/GO was characterized, and the photocatalytic performance of nitrogen fixation to ammonia was discussed. It was found that coal-based SiO₂/GO as a carrier not only improved the dispersion of Ag nanoparticles through avoiding the agglomeration, but also improved the absorption of visible light of the composite photocatalyst, which in turn improved the performance of Ag/SiO₂/GO for ammonia synthesis. The ammonia yield reached 449.32 μmol L⁻¹ g⁻¹·cat when 80%-Ag/SiO₂/GO was used as photocatalyst reacting for 4 h. Besides, the composite photocatalyst had good stability and lifetime. The ammonia yield could still reach 82.49% after five cycles.

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