화학공학소재연구정보센터
Catalysis Today, Vol.340, 152-160, 2020
Carbon dots modified WO2-NaxWO3 composite as UV-Vis-NIR broad spectrum-driven photocatalyst for overall water splitting
The utilization of solar energy and valid photocatalyst is one of the most effective strategies to achieve water splitting into hydrogen (H-2) and oxygen (O-2). Although enormous effort has been devoted to photocatalysts, the sunlight still cannot be fully utilized by the developed photocatalysts. It is important but remains challenging to develop a broad spectrum-driven photocatalyst for overall water splitting. Here, we design a UV-Vis-NIR broad spectrum-driven carbon dots modified WO2-NaxWO3 (WO2-NaxWO3-CDs) composite as photocatalyst for overall water splitting without requirement of any sacrificial agents or cocatalysts. When the concentration of CDs in the sample is 0.008 g(CDs)/g(catalyst), the WO2-NaxWO3-CDs shows the highest photocatalytic activity with stoichiometric ratio of H-2/O-2 evolutions and their rates are 0.05/0.02, 2.58/1.24, 4.74/2.28 mu mol/h under UV (lambda < 420 nm), visible (420 nm <= lambda <= 760 nm) and near-infrared (lambda > 760 nm) light irradiation, respectively. It is also impressive that the photocatalyst shows excellent stability for about 6 cycles of repetitive experiments. The WO2-NaxWO3-CDs composites functioned as broad spectrum-driven photocatalyst for overall water splitting should attribute to the synergistic effect of WO2-NaxWO3 and CDs, in which the WO2-NaxWO3 provides the suitable bandgap, while the CDs can enhance light absorption and accelerate separation efficiencies of photo-generated charge carriers.