Constructing Surface Plasmon Resonance on BiWO to Boost High-Selective CO Reduction for Methane.

Plasmonic BiWO with strong localized surface plasmon resonance (LSPR) around the 500-1400 region is successfully constructed by electron doping. Oxygen vacancies on W-O-W (V1) and Bi-O-Bi (V2) sites are precisely controlled to obtain BiWO-V with LSPR and BiWO-V with defect absorption. Density functional theory (DFT) calculation demonstrates that the V1-induced energy state facilitates photoelectron collection for a long lifetime, resulting in LSPR of BiWO. Photoelectron trapping on V1 sites is demonstrated by a single-particle photoluminescence (PL) study, and 93% PL quenching efficiency is observed. With strong LSPR, plasmonic BiWO-V exhibits highly selective methane generation with a rate of 9.95 μmol g h during the CO reduction reaction (CO-RR), which is 26-fold higher than 0.37 μmol g h of BiWO-V under UV-visible light irradiation. LSPR-dependent methane generation is confirmed by various photocatalytic results of plasmonic BiWO with tunable LSPR and different light excitations. Furthermore, the DFT-simulated pathway of CO-RR and Fourier transform infrared spectra on the surface of BiWO prove that V1 sites facilitate CH generation. Our work provides a strategy to obtain nonmetallic plasmonic materials by electron doping.