Plasmonic Active “Hot Spots”‐Confined Photocatalytic CO2 Reduction with High Selectivity for CH4 Production

• Published in: Advanced materials (Weinheim) Vol. 34; no. 14; pp. e2109330 - n/a
• Main Authors: Jiang, Xiaoyi, Huang, Jindou, Bi, Zhenhua, Ni, Wenjun, Gurzadyan, Gagik, Zhu, Yongan, Zhang, Zhenyi
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.04.2022
• Subjects: Carbon dioxide; CH 4 production; CO 2 photoreduction; dual‐hetero‐active‐sites; Gold; Heterostructures; Hot electrons; Incident light; Materials science; metal/nonmetal plasmon coupling; Methane; Nanofibers; Nanoparticles; Nanowires; Photocatalysis; plasmonic “hot spots”; Plasmonics; Protons; Reduction; Selectivity; Titanium dioxide
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202109330

Plasmonic nanostructures have tremendous potential to be applied in photocatalytic CO2 reduction, since their localized surface plasmon resonance can collect low‐energy‐photons to derive energetic “hot electrons” for reducing the CO2 activation‐barrier. However, the hot electron‐driven CO2 reduction is usually limited by poor efficiency and low selectivity for producing kinetically unfavorable hydrocarbons. Here, a new idea of plasmonic active “hot spot”‐confined photocatalysis is proposed to overcome this drawback. W18O49 nanowires on the outer surface of Au nanoparticles‐embedded TiO2 electrospun nanofibers are assembled to obtain lots of Au/TiO2/W18O49 sandwich‐like substructures in the formed plasmonic heterostructure. The short distance (< 10 nm) between Au and adjacent W18O49 can induce an intense plasmon‐coupling to form the active “hot spots” in the substructures. These active “hot spots” are capable of not only gathering the incident light to enhance “hot electrons” generation and migration, but also capturing protons and CO through the dual‐hetero‐active‐sites (Au‐O‐Ti and W‐O‐Ti) at the Au/TiO2/W18O49 interface, as evidenced by systematic experiments and simulation analyses. Thus, during photocatalytic CO2 reduction at 43± 2 °C, these active “hot spots” enriched in the well‐designed Au/TiO2/W18O49 plasmonic heterostructure can synergistically confine the hot‐electron, proton, and CO intermediates for resulting in the CH4 and CO production‐rates at ≈35.55 and ≈2.57 µmol g−1 h−1, respectively, and the CH4‐product selectivity at ≈93.3%. A novel idea of plasmonic active “hot spot”‐confined photocatalytic CO2 reduction is proposed and realized in the well‐designed Au/TiO2/W18O49 plasmonic heterostructure. These active “hot spots” can not only generate high‐energy hot electrons, but also adsorb intermediate products of CO and protons, thereby resulting in high photocatalytic activity and selectivity for CH4 production.