A Mg-AI layered double hydroxide (LDH) was prepared from Mg(NO3)2 · 6H2O and AI((NO3)3 · 9H1O by a constant-pH co-precipitation method at room temperature. PdCI2-4~ was successfully introduced into the gallery space of the Mg-AI-LDH via an ion exchange process, and then reduced by hydrazine to produce LDH-supported palladium (LDH-Pd0) nanomaterials. The sample was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). It was found that palladium nanoparticles were well dispersed on the LDH surface. The LDH-Pd0 nanomaterial was immobilized on a glassy carbon electrode (GCE) to oxidize hydrazine in a phosphate buffer solution (PBS, pH 7.0) using cyclic voltammetry (CV). The modified electrode exhibited excellent electrocatalytic activity and thus could be used to determine the concentration of hydrazine. This was verified by examining the amperometric response at a working potential of-0.1 V, where it was found that the anodic peak current of the modified electrodes was linear with hydrazine concentration in the range of 1.0×10-5-2.0*10-4 mol-L-1. The detection limit was 9.5×107 mol·L-1 at a signal-to-noise ratio of 3. The electrochemically effective surface areas were determined by chrono-coulometry (CC) to be 0.02089, 0.02762, and 0.02496 cm2 for GCE, LDH-Pd0/GCE, and LDH/GCE, respectively. The irreversible oxidation of hydrazine on the modified electrode is diffusion controlled with the participation of four electrons and four protons.%利用共沉淀方法制备了载体水滑石(LDH),通过离子交换法将PdCl42-插入水滑石层间,再用水合肼将其还原,制备得到了水滑石负载的分散状钯纳米粒子(LDH-Pd0).利用X射线衍射(XRD)、透射电镜(TEM)和X射线电子能谱(XPs)等手段对所得样品进行了表征,结果表明钯纳米粒子能很好地分散在水滑石上.将该纳米材料修饰的玻碳电极(GCE)用于水合肼的电催化氧化,该修饰电极表现出很好的电化学催化活性.用循环伏安法(CV)、计时库仑法(CC)和计时安培法(i-t)对修饰电极的催化活性、有效表面积和水合肼的催化氧化机理等进行了研究.结果表明水合肼在-0.1 V附近有明显的氧化峰,在1.0×10-6-2.0×10-4 mol·L-1范围内,阳极峰电流与水合肼浓度间有良好的线性关系,其检测限为9.5×10-7 mol·L-1.计算得到GC E,LDH-Pd0/GCE和LDH/GCE 电极活化面积分别为0.02089,0.02762和0.02496 cm2.推知水合肼的氧化过程有4电子和4质子参与,并且其在电极上的反应是受扩散控制的不可逆过程.
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