Improved visible-light catalytic activities of novel Au/P-doped g-C3N4 photocatalyst for solar fuel production and mechanism

Abstract

The noble metal decorated photocatalytic materials have received marvelous attention in recent decade owing to their exceptional applications in energy conversion and environmental remediation. Herein, we have successfully fabricated Au decorated phosphorus doped graphitic carbon nitride (Au/P-CN) photocatalyst for the first time via ionic liquid and in situ photo-reduction methods. The resultant photocatalyst exhibits significant visible-light activities for water splitting to evolve H2 and CO2 conversion to CH4. The amount of H2 evolved over Au/P-CN photocatalyst is 97 μmol, ∼12-fold enhanced compared to that of the bare CN (8 μmol). Similarly, the amount of CH4 produced over Au/P-CN photocatalyst is 24 μmol, about 6-fold enhanced compared to that of the bare CN (4 μmol). The calculated quantum efficiencies for H2 evolution and CH4 production are ∼3.60% and ∼2.83%, respectively at λ = 420 nm. The exceptional photocatalytic activities are attributed to the extended visible-light absorption and improved charge carriers separation via the dopant induced surface states and the well decorated Au nanoparticles. This work demonstrate that the Au decorated CN-based photocatalysts show promising applications in photocatalysis for water splitting to evolve H2 and CO2 conversion to CH4 under visible-light irradiation.