Plasmon assisted highly efficient visible light catalytic CO2 reduction over the noble metal decorated Sr-incorporated g-C3N4

Abstract

The photocatalytic performance of g-C3N4 for CO2 conversion is still inadequate by several shortfalls including the instability, insufficient solar light absorption and rapid charge carrier's recombination rate. To solve these problems, herein, noble metals (Pt and Au) decorated Sr-incorporated g-C3N4 photocatalysts are fabricated via the simple calcination and photo-deposition methods. The Sr-incorporation remarkably reduced the g-C3N4 band gap from 2.7 to 2.54 eV, as evidenced by the UV-visible absorption spectra and the density functional theory results. The CO2 conversion performance of the catalysts was evaluated under visible light irradiation. The Pt/0.15Sr-CN sample produced 48.55 and 74.54 µmol h-1 g-1 of CH4 and CO, respectively. These amounts are far greater than that produced by the Au/0.15Sr-CN, 0.15Sr-CN, and CN samples. A high quantum efficiency of 2.92% is predicted for the Pt/0.15Sr-CN sample. Further, the stability of the photocatalyst is confirmed via the photocatalytic recyclable test. The improved CO2 conversion performance of the catalyst is accredited to the promoted light absorption and remarkably enhanced charge separation via the Sr-incorporated mid gap states and the localized surface plasmon resonance effect induced by noble metal nanoparticles. This work will provide a new approach for promoting the catalytic efficiency of g-C3N4 for efficient solar fuel production.