Controlled assemble of hollow heterostructured g-C3N4@CeO2 with rich oxygen vacancies for enhanced photocatalytic CO2 reduction

Hollow heterostructured g-C3N4@CeO2 photocatalysts with rich oxygen vacancies are controllable designed by a facile strategy. The synergetic effect and oxygen vacancies of g-C3N4@CeO2 play the major role in the process of CO2 reduction, leading to CH4 generating much earlier and higher concentration than that of the pristine g-C3N4 and CeO2 alone. Meanwhile, the unique hollow structures can make multiple reflections of light in the cavity, and thus enhance the utilization efficiency of light. Moreover, the L-cysteine offers amine groups and meanwhile is anchored on the surface of g-C3N4 during the synthesis process, and thus contributes greatly to the enhanced CO2 adsorption capability. Additionally, the large CO2 adsorption capability is also beneficial for the enhanced photocatalytic activity. Therefore, the novel photocatalysts exhibit a remarkable reduction performance for CO2 reduction under visible light irradiation. The g-C3N4@CeO2 (CeO2 49.7 wt %) shows the highest yields of CH4 (3.5 μmol g−1), CH3OH (5.2 μmol g−1) and CO (16.8 μmol g−1), which are higher than most of other latest reported g-C3N4 based photocatalysts for CO2 photoreduction, including coupled with semiconductors and noble metal cocatalysts. This strategy might represent a novel way for the effective conversion of CO2 to clean fuels and can also be great potential used in the energy and environmental science.