Mesostructured CeO2/g-C3N4 nanocomposites: Remarkably enhanced photocatalytic activity for CO2 reduction by mutual component activations

CO2 is highly stable and therefore extremely difficult to be reduced at room temperature. Herein, mesostructured CeO2/graphite carbon nitride (m-CeO2/g-C3N4) was designed and synthesized through a hard-template route. The heterogeneous nanocomposites showed greatly enhanced response to solar light, promoted charge carrier separation and transfer efficiency. Consequently, their CO2 photoreduction performance has been remarkably enhanced. Maximum CO and CH4 yields of 0.590 and 0.694 μmol, respectively, have been obtained from the CO2 reduction after one hour irradiation at room temperature on 50 mg nanocomposite photocatalyst. Different from common g-C3N4-based composites in which the additional component only plays a role of electron sink in electron–hole separation, a synergetic effect of mutual activations between the two components is proposed, which is featured with g-C3N4 activation due to significantly promoted separation of photo-generated carriers under Xenon lamp irradiation, and CeO2 activation via the reduction of Ce4+ to Ce3+ by the trapped electrons.