Gas-solid photo-catalytic reduction of CO2 to CO on calcined sulfonated cobalt phthalocyanine/ZnO/reduced graphene oxide under simulated sunlight

Preventing climate change and achieving carbon neutralization depend on strengthening the carbon cycle in industry and limiting carbon emissions to ambient air. Our aim is to reduce CO2 to valuable CO by gas-solid photo-catalytic reduction under sunlight. We prepared catalysts by one-step synthesis with graphene oxide (GO) and ZnO, surface modified with a monolayer of sulfonated cobalt phthalocyanine (CoPcS), which were calcined to obtain photocatalyst samples containing Co(II), ZnO and reduced graphene oxide (rGO). Results of TEM, SEM-EDS, XRD, XPS, PL and ESR revealed that the photocatalyst samples possessed a hybrid layer microstructure, heterojunction, and excellent electron-hole pair separation. Evaluation of the photocatalytic reduction reactivity showed that CO selectivity reached 96.2–99.0% and top CO yield was 26.15 µmol.g−1.h−1.