High efficiency of graphene/CoFe2O4 nanomaterial in the photocatalytic conversion of CO2 dissolved in water under solar irradiation simulator

The present work describes the excellent performance of GH–CoFe2O4 photocatalysts based on graphene ferrite, synthesized using water rich in natural organic matter (NOM) as a solvent, for the photocatalytic reduction of CO2 under artificial visible light, at ambient temperature and pressure. The nano-photocatalysts presented excellent photocatalytic activity, with high selectivity towards the conversion of CO2 to methanol as the main product, for both semiconductors tested (CoFe2O4 and GH–CoFe2O4). The presence of graphene improved photoexcitation under visible light, decreasing the CoFe2O4 band gap value from 1.47 to 1.25 eV, resulting in decreased recombination of the e−/h+ pairs. The rates of formation of methanol were 1105.7 and 1389.9 µmol g−1 h−1 for CoFe2O4 and GH–CoFe2O4, respectively. The findings reveal the potential of photocatalysts based on ferrite and graphene for use in the conversion of CO2 dissolved in water without any added chemical into high added-value products.