Photothermally assisted photocatalytic conversion of CO2–H2O into fuels over a WN–WO3 Z-scheme heterostructure

Abstract

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, infrared light in the solar spectrum is not utilized properly in most traditional photocatalytic reactions. Thus, the search for photocatalysts that exploit the wide solar spectrum to achieve an efficient water-based CO₂ conversion performance is still highly challenging. Herein, we construct a 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 5 h 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 the WN–WO₃ heterostructure under ultraviolet-visible illumination. In addition, the infrared light in sunlight is also utilized by the WN–WO₃ heterostructure to generate heat via photo-to-thermal conversion, which further accelerates such a conversion reaction. This work offers a unique perspective for designing transition metal nitride/oxide heterostructures and paves a new way to boost the CO₂-to-fuel conversion performance.