Photothermally Assisted Photocatalytic Conversion of CO2-H2O into Fuels over a WN-WO3 Z-Scheme Heterostructure

The CO2 conversion into value-added fuels has been considered as a promising solution to solve environmental problems and energy crises. However, the efficiency of photocatalytic CO2 conversion is low. In addition, the infrared light in solar spectrum is not utilized properly in most traditional photocatalytic reaction. Thus, the search of photocatalysts that exploit the wide solar spectrum to achieve efficient water-based CO2 conversion performance is still highly challenged. Herein, we construct WN-WO3 Z-scheme heterostructure to exploit the wide solar spectrum for efficient CO2-H2O conversion into fuels (H2, CO, and CH4) without any sacrificial agents. After 5h irradiation, the yields of H2, CO, and CH4 are 3.0, 1.4, and 1.9 times higher than that of WN, respectively. The activity improvement is ascribed to the direct Z-scheme mechanism of WN-WO3 heterostructure under ultraviolet-visible illumination. In addition, the infrared light in sunlight is also utilized by WN-WO3 heterostructure to generate heat via photo-to-thermal conversion, which further accelerates such conversion reaction. This work offers a unique perspective for designing transition metal nitride/oxide heterostructures and paves a new avenue to boost CO2-to-fuels conversion performance.