Combing Hollow Shell Structure and Z-Scheme Heterojunction Construction for Promoting CO2 Photoreduction

CO2 photoreduction is considered one of the potential ways to achieve carbon neutralization since it uses green solar energy without introducing additional carbon sources during the process of converting CO2 to fuels. However, limited light utilization and poor charge separation often give rise to undesirable CO2 photoreduction performance. Herein, a generic approach using carbon spheres as templates to construct transition metal oxides with multishelled hollow structures is reported. The multishelled hollow structure has been proven to be efficient for improving CO2 photoreduction. Furthermore, we constructed a Z-scheme heterojunction photocatalyst (CdS/Au/ZnCrO4) through introducing CdS into a multishelled hollow ZnCrO4 sphere with Au nanoparticles as a charge transfer medium. Benefiting from the multishelled hollow structure's induced light utilization and large surface area and Z-scheme heterojuncion promoted charge separation, a high CO production of 2.95 μmol g–1 h–1 was achieved on CdS/Au/ZnCrO4 without using any sacrificial agents, which was 18.4 times and 24.6 times higher than that of CdS and ZnCrO4. This work provides a generic method for constructing controllable multishelled hollow spheres and is expected to offer guidance for promoting CO2 photoreduction through structure regulation and heterojunction construction.