Core-Shell Structure Dependent Reactivity of Fe@Fe_2O_3 Nanowires on Aerobic Degradation of 4-Chlorophenol

摘要

In this study, core-shell Fe@Fe_2O_3 nanowiresrnwith different iron oxide shell thickness were synthesizedrnthrough tuning water-aging time after the reduction of ferricrnions with sodium borohydride without any stirring. We foundrnthat these Fe@Fe_2O_3 nanowires exhibited interesting wre-rnshell structure dependent reactivity on the aerobic degradationrnof 4-chlorophenol. Characterization results revealed that therncore-shell structure dependent aerobic oxidative reactivity ofrnFe@Fe_2O_3 nanowires was arisen from the combined effects ofrnincrassated iron oxide shell and more surface bound ferrous ions on amorphous iron oxide shell formed during the water-agingrnprocess. The incrassated iron oxide shell would gradually block the outward electron transfer from iron core for the subsequentrntwo-electron molecular oxygen activation, but more surface bound ferrous ions on iron oxide shell with prolonging aging timerncould favor the single-electron molecular oxygen activation, which was confirmed by electron spin resonance spectroswpy withrnspin trap technique. The mineralization of 4-chiorophenol was monitored by total organic carbon measurement and the oxidativerndegradation intermediates were analyzed by gas chromatography-mass spectrometry. This study provides new physical insightrnon the molecular oxygen activation mechanism of nanoscale zerovalent iron and its application on aerobic pollutant removal.