Preparation Of Nickel-based Nanowire Arrays And Study On Electrocatalytic Oxidation Degradation Of Urea

Transition metals and their oxides or complexes with other active materials have excellent catalytic properties;nanowire array structures have high specific surface area and can increase the active sites in catalytic reactions by preparing nanowire arrays with surface defects.By alloying,the activation energy of the catalytic reaction can be reduced,so that alloy nano-arrays with high catalytic activity can be prepared.Based on this idea,nickel-based nanowire arrays were prepared by electrodeposition of anodized aluminum oxide?AAO?templates.The morphology and structure of nickel-based nanowire arrays were characterized by field emission scanning electron microscopy?SEM?and X-ray diffraction?XRD?.Cyclic voltammetry?CV?,chronoamperometry and electrochemical impedance spectroscopy?EIS?were used to study the activity of nickel-based nanowire arrays for the electrocatalytic oxidation of urea.Using AAO as a template,nickel nanowire arrays and nickel-cobalt alloy nanowire arrays were prepared by using carbon conductive adhesives to bond AAO templates and nickel-cobalt alloy nanowire arrays deposited by foamed nickel-fixed AAO templates.The results of XRD showed that both nickel nanowires and nickel-cobalt alloy nanowires were fabricated.The face-centered cubic structure,SEM results show that the average diameter of the nanowires is 180 nm,the nanowires themselves have a larger aspect ratio,and highly ordered nanowire arrays are in contact with the substrate through the alloy layer,and have a strong binding force,and The length of nanowires can be controlled by controlling the electrodeposition time.The nanowires with a deposition time of 400 s-700s grow gradually.When the deposition time is 600 s,the length of the Ni-Co alloy nanowires with a length of approximately 10?m just does not agglomerate.As it continued to grow,the length of nanowires also increased and there was a clear agglomeration between nanowires.The results of electrocatalytic oxidation of urea showed that the nickel-cobalt alloy nanowires prepared from the carbon conductive paste adhered to the AAO template had an initial potential of 0.45 V?vs.Hg/HgO?and an oxidation current density of 64.3 mA cm^-2.Nickel-cobalt alloy nanowires were prepared by electrodeposition of foamed nickel-fixed AAO template.The deposition time was 600 s,which had the lowest initial potential?0.372 V vs.Hg/HgO?and the highest oxidation current density?322.82 mA cm-2?.Compared to the test results of nickel-cobalt alloy nanowires prepared by using carbon conductive adhesive template,the improvement of the efficiency of electrocatalytic oxidation of urea by using nickel-cobalt alloy nanowire arrays is due to the fact that one-dimensional free-standing nickel-cobalt alloy nanowire arrays have more The active site,directly in contact with the substrate,facilitates electron transfer and improves the performance of electrocatalytic oxidation of urea.