Preparation Of Hierarchically Hollow CuSiO/CuO_x Nanofibers And Their Application In Environmental Improvement

With the rapid development of the economy,energy over-consumption and environmental pollution problemhave become two serious issues,which not only damages the ecological environment,but also endangers the survival and development of human beings.The remediation of environmental is imminent.Catalytic degradation of pollutants is one of the most direct and effective methods to curb the environmental pollution.However,traditional catalysts have limited development and practical applications due to their low activity,high cost and difficulty for recovery in the catalytic system.Therefore,it is particularly important to develop a cheap and green catalyst with high catalytic activity and recyclability.Among many materials,metal silicate exhibits great catalytic potential and application prospects in environmental treatment because of its good chemical stability and low price.In this paper,three kinds of silicate-based catalysts have been prepared by combining the electrospinning technique,hydrothermal method and high-temperature reduction method,and their structures,compositions and morphologies have also been characterized by XRD,XPS,TEM,SEM and etc.In addition,we investigated the performance of the catalyst on the adsorption of organic dyes,the reverse water gas shift reaction?RWGS?and the reduction of4-nitrophenol as model reactions.The specific contents are as follows:?1?SiO₂ hollow nanofibers were firstly synthesized by electrospinning and hydrothermal method,then hierarchical double-walled CuSiO hollow nanofibers were obtained with the SiO2 hollow nanofibers as a template.The adsorption properties of double-walled CuSiO hollow nanofibers on different organic dyes,such as methylene blue,rhodamine B and malachite green organic dyes,have also been investigated.The results showed that CuSiO hollow nanofibers exhibited good adsorption properties on organic dyes.?2?As a Cu source and supporter,double-walled CuSiO hollow nanofibers were calcined in hydrogen atmosphere to prepare CuO_x/CuSiO composite nanofibers by an in situ self-reduction method.Well-dispersed CuO_x NPs on the surface of CuSiO nanofibers with a small size had a strong interaction with CuSiO supporter.The composite nanofibers were used as a catalyst in reverse water gas shift reaction.The results showed that the CuO_x/CuSiO composite nanofibers synthesized by an in situ self-reduction method had a better catalytic activity than that of the Cu/TiO₂ and Cu/SiO₂ nanocomposites obtained from the impregnation method.?3?Fibrous CuO_x/CuSiO-X nanocomposites were prepared by the high temperature reduction of double-walled CuSiO hollow nanofibers in the hydrogen atmosphere at different time,which was used as catalysts in the reduction of 4-nitrophenol?4-NP?.The catalytic activities of the products obtained at different reduction time were compared the.The experimental results demonstrated that the CuO_x/CuSiO-X composite nanofibers obtained with the reduction time of 2 h exhibited the highest catalytic activity.CuO_x/CuSiO-X nanofibers also showed good catalytic activities in the catalytic reduction of 2-nitrophenol,3-nitrophenol,4-nitroaniline and 4-nitrochlorobenzene.