Surface plasmon resonance and defects on tungsten oxides synergistically boost high-selective CO2 reduction for ethylene

Photocatalytic CO2 reduction reaction (CO2-RR) driven by solar energy is one expected “green technology” to produce hydrocarbon, however, the high-valuble C2/Cx-compounds converted from CO2 face great challenges. Herein, high-selective ethylene production is achieved via photocatalytic CO2-RR by using plasmonic tungsten oxides as catalyst under solar light irradiation. Tungsten oxides (WO3-x-2) synthesized by using acid-assisted solvothermal method exhibits thin amorphous surface structure with abundant oxygen vacancies and low-valence tungsten ions (26.1 mol% W5+ and 7.1 mol% W4+). Under full-spectrum light irradiation, ethylene generation rate of WO3-x-2 is 61.6 μmol g − 1 h − 1 (selectivity of 89.3%) and is 20-fold higher than that of WO3-x-0 with thick amorphous surface. The amorphous surface of tungsten oxides with abundant defects is clearly observed by atomic-resolution high-angle annular dark field scanning transmission electronic microscopy (HAADF-STEM). Light-dependent photocatalytic results demonstrate the synergetic effect of oxygen vacancies, plasmonic hot electrons and photothermal heating boosting CO2-RR on tungsten oxide catalysts for ethylene generation. One possible ethylene generation pathway is proposed based on the detected intermediates during CO2-RR. As far as we known, our work is the first report on plasmonic photocatalytic CO2-RR for high-selective ethylene generation.