Superlattice‐based Plasmonic Catalysis: Concentrating Light at the Nanoscale to Drive Efficient Nitrogen‐to‐Ammonia Fixation at Ambient Conditions

• Published in: Angewandte Chemie 2023-02, Vol.135 (7), p.n/a
• Main Authors: Boong, Siew Kheng, Chong, Carice, Lee, Jinn‐Kye, Ang, Zhi Zhong, Li, Haitao, Lee, Hiang Kwee
• Format: Article
• Language: English
• Subjects: Ammonia; Ammonia Generation; Catalysis; Catalysts; Chemical synthesis; Chemistry; Electromagnetic fields; Gas-to-Fuel/Chemical; Hot electrons; Nitrogen; Nitrogen Fixation; Plasmonic Catalysis; Plasmonics; Superlattice; Superlattices
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202216562

Plasmonic catalysis promises green ammonia synthesis but is limited by the need for co‐catalysts and poor performances due to weak electromagnetic field enhancement. Here, we use two‐dimensional plasmonic superlattices with dense electromagnetic hotspots to boost ambient nitrogen‐to‐ammonia photoconversion without needing co‐catalyst. By organizing Ag octahedra into a square superlattice to concentrate light, the ammonia formation is enhanced by ≈15‐fold and 4‐fold over hexagonal superlattice and disorganized array, respectively. Our unique catalyst achieves superior ammonia formation rate and apparent quantum yield up to ≈15‐fold and ≈103‐fold, respectively, better than traditional designs. Mechanistic investigations reveal the abundance of intense plasmonic hotspots is crucial to promote hot electron generation and transfer for nitrogen reduction. Our work offers valuable insights to design electromagnetically hot plasmonic catalysts for diverse chemical and energy applications. Organizing anisotropic plasmonic nanoparticles into a two‐dimensional superlattice is important to intensify the electromagnetic field at both the single‐particle and ensemble levels for efficient nitrogen‐to‐ammonia photoconversion at ambient conditions. Our unique superlattice‐based plasmonic catalysts boost the ammonia formation rate and apparent quantum efficiency by up to ≈15‐fold and ≈103‐fold, respectively, when compared to traditional photocatalytic and hybrid plasmonic‐photocatalytic designs.