Preparation Of Silicon Nanowires And Its Application In The Field Of Catalysis

Due to large specific surface area,good physical and chemical stability,the unique optical,electrical,and mechanical properties,field emission,and thermoelectric performance,Si NWs have widely applied in many fields,such as sensors,lithium ion battery,photoelectrochemical cells,photovoltaic,catalysis,etc.The Si NWs recombined with some metal particles have been used extensively in the catalytic field.However,the study on the relationship between microstructure and function of Si NWs is inadequate.Additionally,the applied range of Si NWs should be further developed.Based on the above situation,Si NWs arrays with different orientation crystal phases were prepared.Their fabricating,catalytic performance and catalytic mechanism are studied in this work.The main research contents are as follows:（1）Enhanced photodegradation activity of hydrogen-terminated Si NWs arrays with different orientation crystal phases:Si NWs arrays with different crystal orientations were prepared via a metal-assisted chemical etching method,which considered as an alternative method for fabricating high-productivity Si NWs with simple process,lower cost and short production time.Their dye photodegradation activities were systematically and comprehensively investigated.Si NWs arrays with（100）crystal orientation exhibit a superior photodegradation activity and stability due to the anisotropy of optical and physical properties.The n-type Si NWs arrays exhibit better photodegradation activity than that of p-type Si NWs arrays with the same crystal orientation and similar length.（2）Application of p-type silicon nanowires in the field of ozone decomposition:the p-type Si NWs exhibit 90%ozone（20 ppm O₃/air）decomposition efficiency with great stability,which is much better than that of n-type Si NWs（50%）with same crystal orientation,similar diameter and specific surface area.The catalytic property difference is mainly attributed to the more delocalization holes in the p-type Si NWs,which can accelerate the desorption of ozone decomposition intermediates（i.e.,adsorbed oxygen species）.