All-solid-state Z-scheme photocatalysts of g-C3N4/Pt/macroporous-(TiO2@carbon) for selective boosting visible-light-driven conversion of CO2 to CH4

Abstract

The artificial photosynthesis for visible-light-driven CO2 reduction with H2O is promising to solve both energy and environmental issues simultaneously. Herein, we have successfully fabricated all-solid-state Z-scheme ternary photocatalysts, consisting of two isolated photochemical systems of graphitic carbon nitride (g-C3N4) and three-dimensional ordered macroporous carbon-coated TiO2 (3DOM-TiO2@C) combined with Pt nanoparticles as electron-transfer system. Photonic crystal structure and carbon-coated nanolayers of 3DOM-TiO2@C support enhance visible light-harvesting efficiency. The vectorial photoelectron transferring of TiO2@C → Pt → g-C3N4 boosts the separation and surface enrichment efficiencies of photogenerated electrons and holes. All-solid-state Z-scheme ternary photocatalyst exhibits the outstanding yields of CH4 (6.56 μmol h−1, 0.1 g catalyst) and high-efficient quantum efficiency (5.67%) during visible-light-driven conversion of CO2 with H2O. The surface enrichment of electrons and CO2 is the rate-determining step of selective CO2 photoreduction. This study is expected to throw new light on the fabrication of high-efficient photocatalyst for CO2 conversion to hydrocarbon.