Efficient photothermal-assisted photocatalytic NO removal on molecular cobalt phthalocyanine/Bi2WO6 Z-scheme heterojunctions by promoting charge transfer and oxygen activation

Developing a high-performance photocatalyst with an efficient charge transfer pathway and reasonable active sites for photocatalytic NO removal is a formidable challenge. Herein, a novel Z-scheme molecular cobalt phthalocyanine(CoPc)/Bi2WO6 photothermal-assisted photocatalyst was elaborately designed. The interfacial Co-O-W bond and built-in electric field(BIEF) between Bi2WO6 and CoPc promote a cascade Z-scheme charge transfer system from Bi2WO6 to CoPc, thereby facilitating the charge separation and retaining high redox potential. Meanwhile, the Co-N4(II) sites of CoPc can capture more photoexcited electrons migrating from Z -scheme of the CoPc/Bi2WO6 composite, which facilitates the electron transfer to O-2 for the generation of center dot O-2(-) . Moreover, the photothermal effect of CoPc can further improve the O-2 activation efficiency. Consequently, the obtained photocatalysts exhibit superior photocatalytic activity for NO removal (74.9%) and lower generation of toxic NO2 (< 6 ppb) by-products compared with pristine Bi2WO6. This work offers a new idea for constructing high-efficiency NO photo-oxidation systems.

Automated summary

In this study, a novel Z-scheme molecular photocatalyst was designed, in which the interfacial bonds and built-in electric field between Bi2WO6 and CoPc promoted charge transfer and the CoPc sites facilitated electron transfer and activation of oxygen molecules. The experimental results demonstrated that the photocatalyst exhibited superior activity for NO removal.