Cooperation plasmonic Ag nanoparticles with TiO_2−x/AgFeO₂ nanocomposite for effectual photocatalytic NH₃ generation

Photocatalytic ammonia synthesis, as a sustainable and renewable strategy, could have a great contribution to the suppression of the energy crisis. Herein, TiO_2−x/AgFeO₂/Ag is developed with oxygen vacancies through hydrothermal conditions, which are accompanied with the surface plasmon resonance of silver nanoparticles. Impressively, the maximal ammonia evolution rate over TiO_2−x/AgFeO₂/Ag nanocomposite reached 28,491 µmol L⁻¹ g⁻¹, which was 7.42 and 2.70 times higher than that of TiO₂ and AgFeO₂/Ag photocatalysts. Oxygen vacancies were considered as the active centers to effectively adsorb and activate dinitrogen molecules, while silver nanoparticles generated hot electrons through surface plasmon resonance by effectual harnessing solar energy. The synergy of surface plasmon resonance and oxygen vacancies results in the enhanced carriers segregation as well as electron transition to nitrogen, thereby leading to improved nitrogen adsorption and activation over modified TiO_2−x/AgFeO₂/Ag nanocomposite. Moreover, ammonia evolution rate hardly decreased after 15 h course of reaction, and the ammonia evolution rate reached 24,564 µmol L⁻¹ g⁻¹ in the fifth run, demonstrating the supreme photocatalytic stability. Thereby, the outcomes will shed new insight on rational engineering of catalysts, activation centers, and carriers segregation for effectual photocatalytic nitrogen reduction.