Synergy of MoO2 with Pt as Unilateral Dual Cocatalyst for Improving Photocatalytic Hydrogen Evolution over g-C3 N4.

ABSTRACT

Pt is usually used as cocatalyst for g-C3 N4 to produce H2 by photocatalytic splitting of water. However, the photocatalytic performance is still limited by the fast recombination of photo-generated electrons and holes, as well as the poor absorption of visible light. In this work, MoO2 /g-C3 N4 composites were prepared, in which MoO2 synergetic with Pt photo-deposited during H2 evolution reaction worked as unilateral dual cocatalyst to improve the photocatalytic activity. Within 4 hours of irradiation, the hydrogen production rate of MoO2 -Pt dual cocatalyst modified g-C3 N4 reached 3804.89 µmol/g/h, which was 120.18 times of that of pure g-C3 N4 (GCN, 31.66 µmol/g/h), 10.98 times of that of MoO2 modified g-C3 N4 (346.39 µmol/g/h), and 9.18 times of that of Pt modified g-C3 N4 (413.64 µmol/g/h). Characterization results demonstrate that the deficient MoO2 not only promoted visible light absorption of g-C3 N4 , but also worked as a "electron pool" to capture and transfer electrons to Pt.