Synergy of MoO 2 with Pt as Unilateral Dual Cocatalyst for Improving Photocatalytic Hydrogen Evolution over g-C 3 N 4 .

Pt is usually used as cocatalyst for g-C 3 N 4 to produce H 2 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, MoO 2 /g-C 3 N 4 composites were prepared, in which MoO 2 synergetic with Pt photo-deposited during H 2 evolution reaction worked as unilateral dual cocatalyst to improve the photocatalytic activity. Within 4 hours of irradiation, the hydrogen production rate of MoO 2 -Pt dual cocatalyst modified g-C 3 N 4 reached 3804.89 μmol/g/h, which was 120.18 times of that of pure g-C 3 N 4 (GCN, 31.66 μmol/g/h), 10.98 times of that of MoO 2 modified g-C 3 N 4 (346.39 μmol/g/h), and 9.18 times of that of Pt modified g-C 3 N 4 (413.64 μmol/g/h). Characterization results demonstrate that the deficient MoO 2 not only promoted visible light absorption of g-C 3 N 4 , but also worked as a "electron pool" to capture and transfer electrons to Pt.