S bridging active centers coordination with oxygen vacancy of metastable blue WO3 for efficient C–C coupling and highly selective photoconversion CO2 to ethylene

This study proposes that metastable WO3 exhibits efficient photoconversion of CO2 to ethylene (C2H4). It is found that 1) the metastable hexagonal WO3 (h-WO3) offers a suitable bandgap for CO2 reduction, and its surface oxygen vacancy can enhance the light absorption capability and promote the separation of photogenerated electron-hole pairs, simultaneously; 2) S atoms replace oxygen atoms as the bridges to connect the adjacent W atoms to form W-S-W sites are beneficial to adsorb the *CH2 intermediates. Consequently, the optimized h-WO3 nanorods integrating oxygen vacancy and sulfur doping together have achieved the C2H4 generation yield of 1121.39 μmol g−1 with the record-high yield-based selectivity of 87.6% and electron-based selectivity of 95.7% in the field of photocatalytic CO2 reduction so far. This work provides a new avenue for the realization of CO2 photoconversion to C2+ products on a single metal oxide by virtue of O vacancy and S doping synergistic utilization.