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

Luyue Wang, Xinxin Xu, Zhongmin Feng, Lijun Bian, Yun Wang

Index: 10.1016/j.jssc.2018.04.002

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Abstract

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 to 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 H2 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.