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

Abstract

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 O2 for the generation of •O2-. Moreover, the photothermal effect of CoPc can further improve the O2 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.