WO3-x based composite material with chitosan derived nitrogen doped mesoporous carbon as matrix for oxygen vacancy induced organic pollutants catalytic reduction and IR driven H2 production

A nitrogen doped mesoporous carbon matrix supported tungsten oxide composite material, WO3-x@NC, (1 > x > 0), was fabricated successfully with chitosan and polyoxometalates as precursors through calcination. In this composite material, tungsten oxide particles with the size about 5-8 nm disperse evenly in the framework of nitrogen doped mesoporous carbon matrix. WO3-x@NC exhibits striking catalytic activity for reductive conversion of 4-nitrophenol to 4-aminophenol with the existence of sodium borohydride (NaBH4). The conversion efficiency reaches almost 100% in 2.5 min with a small amount of WO3-x@NC as catalyst. After 5 successive cycles of reactions, this value still retains above 92%. Besides 4-nitrophenol, WO3-x@NC also possesses excellent activity in catalytic removal of organic dyes, such as Rhodamine B (RhB) and methyl orange (MO). Oxygen vacancies from WO2 and good conductivity of nitrogen doped carbon matrix play important roles in the removal of these organic pollutants. WO3-x@NC also possesses outstanding IR light driven photocatalytic H-2 evolution activity. Furthermore, the influence of calcination temperature on catalysis is studied and an ideal condition to obtain catalyst with high activity has been obtained. We expect that WO3-x@NC will find its way as a promising material in water purification as well as a new resource for hydrogen energy.