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

Abstract

Plasmonic nanostructures have tremendous potential to be applied in photocatalytic CO 2 reduction, since their localized surface plasmon resonance can collect low-energy-photons to derive energetic "hot electrons" for reducing the CO 2 activation-barrier. However, the hot electron-driven CO 2 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. W 18 O 49 nanowires on the outer surface of Au nanoparticles-embedded TiO 2 electrospun nanofibers are assembled to obtain lots of Au/TiO 2 /W 18 O 49 sandwichlike substructures in the formed plasmonic heterostructure. The short distance (< 10 nm) between Au and adjacent W 18 O 49 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/TiO 2 /W 18 O 49 interface, as evidenced by systematic experiments and simulation analyses. Thus, during photocatalytic CO 2 reduction at 43± 2 °C, these active "hot spots" enriched in the well-designed Au/TiO 2 /W 18 O 49 plasmonic heterostructure can synergistically confine the hot-electron, proton, and CO intermediates for resulting in the CH 4 and CO productionrates at ≈35.55 and ≈2.57 µmol g −1 h −1 , respectively, and the CH 4 -product selectivity at ≈93.3%.

Plasmon-enhanced photocatalytic overall water-splitting over Au nanoparticle-decorated CaNb2O6 electrospun nanofibers

“…4F, the Au 4f 7/2 and Au 4f 5/2 peaks of Au 1 /CaNb 2 O 6 NFs are positioned at 83.4 and 87.1 eV, respectively, which are in accordance with the corresponding values of the metallic Au 0 state. 50 Meanwhile, the valence states of Ca and Nb ions in both the CaNb 2 O 6 and Au 1 /CaNb 2 O 6 NFs are +2 and +5, respectively (Fig. S13†).…”

P25-induced polydopamine conformal assembly on Cu2O polyhedra for hydrophilic and stable photoelectrochemical performance

“…10,11 A TiO 2 coating is an excellent candidate, which allows photogenerated electrons to transfer through owing to its appropriate conduction band position. 12,13 An atomic layer deposited TiO 2 coating can efficiently improve the stability of the p–n Cu 2 O photocathode in aqueous conditions reported by Gong et al 14 Furthermore, lowering the diffusion energy barrier of photogenerated carriers can be achieved by constructing a semiconductor heterojunction. The formed type-II or direct Z heterojunction by TiO 2 /Cu 2 O provides a strong driving force for charge separation.…”

Alkyl group-decorated g-C3N4 for enhanced gas-phase CO2 photoreduction

“…Photocatalytic CO 2 reduction into high value-added chemical fuels is able to simultaneously mitigate the increasingly severe energy crisis and environmental problems, which is considered as one of the photochemical reactions with the most potential. [1][2][3][4][5][6][7] To apply photocatalytic CO 2 reduction technology in practice, the main research aim is to seek the proper photocatalyst. In recent decades, polymeric g-C 3 N 4 has received great attention as a promising photocatalyst because of its excellent physical and chemical stability, easy synthesis methods, low cost, abundant resources, and visible-light response, etc.…”