Z-Scheme Au@Void@g-C₃N₄/SnS Yolk-Shell Heterostructures for Superior Photocatalytic CO₂ Reduction under Visible Light

Au@g-C₃N₄/SnS yolk-shell Z-scheme photocatalysts are fabricated by a simple template-assisted strategy. The l-cysteine can offer the amine groups and meanwhile anchor on the surface of g-C₃N₄ during solvothermal reaction and thus contributes greatly to the enhanced carbon dioxide adsorption capability. This Z-scheme photocatalytic reduction mechanism of Au@g-C₃N₄/SnS performs valuable functions in the reaction, leading to CH₄ generation much earlier and higher concentration than that of Au@g-C₃N₄. Meanwhile, the unique yolk-shell structure can make the light bounce back and forth in the cavity and thus enhances the availability ratio of light. The application of small amount of noble metal cocatalysts and the large Brunauer-Emmett-Teller surface areas are also benefited for the enhanced photocatalytic activities. Hence, this novel material exhibits a distinguished reduction performance for CO₂ reduction under visible light. The highest yields of CH₄ (3.8 μmol g^-1), CH₃OH (5.3 μmol g^-1), and CO (17.1 μmol g^-1) can be obtained for the sample of Au@g-C₃N₄/SnS (SnS 41.5%), which is higher than 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 transition of CO₂ to clean fuels and can also be enormous feasible utilization in the photocatalytic field.