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通过电沉积法在碳纸表面制备了枝状银微纳结构(Ag-Fr),再利用电置换反应(GRR),在枝状银表面置换上一层钯元素,形成枝状银-钯复合材料(Ag_xPd_y-Fr)。所得复合材料的形貌和成分经过粉末X射线衍射(XRD)、扫描电镜(SEM)、电感耦合等离子体原子发射光谱(ICPOES)等手段表征。利用电化学方法研究了枝状银-钯复合材料Ag_xPd_y-Fr在碱性条件下对乙醇的电催化氧化活性,并与与商业Pd/C催化剂进行了比较。通过对比,在制备的几种催化剂中,Ag_(94)Pd_6-Fr在碱性条件下对乙醇的电催化氧化活性最高。由电催化氧化乙醇(EOR)的循环伏安(CVs)研究可知,乙醇在Ag_(94)Pd_6-Fr上的正向扫描氧化峰电流密度最高,为~33 m A·cm~(-2),约为Pd/C上的11倍,且起始峰电位约比Pd/C上的低0.08 V。乙醇在Ag_(91)Pd_9-Fr和Ag_(87)Pd_(13)-Fr上的正向扫描氧化峰电流密度分别为Pd/C上的9.3倍和5.4倍,起始峰电位分别比Pd/C上的低0.06和0.01 V。当置换时间超过2 h后,枝状结构的细微结构消失,整个结构间的空隙变小,比表面积减小,加上表面AgCl沉淀的生成和覆盖,虽然此时枝状复合材料的钯含量增,但电催化活性较低。
Dendritic silver micro-nanostructures (Ag-Fr) were prepared on the surface of carbon paper by electrodeposition. Replacing the surface of the dendritic silver with a layer of palladium element by electropolishing reaction (GRR) to form dendritic silver-palladium composite Material (Ag_xPd_y-Fr). The morphology and composition of the obtained composites were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and inductively coupled plasma atomic emission spectrometry (ICPOES). The electrocatalytic activity of Ag_xPd_y-Fr, which is a dendritic silver-palladium composite, to ethanol under basic conditions was investigated by electrochemical method and compared with that of commercial Pd / C catalyst. By comparison, the electrocatalytic oxidation of Ag_ (94) Pd_6-Fr to ethanol under alkaline conditions was the highest among the prepared catalysts. The cyclic voltammetry (CVs) of electrocatalytic oxidation of ethanol (EOR) showed that the current density of forward scan oxidation peak of ethanol on Ag 94 Pd 6-Fr was the highest, which was ~ 33 m A · cm -2 About 11 times Pd / C, and the starting peak potential is about 0.08 V lower than that on Pd / C. The forward scan oxidation peak current density of ethanol on Ag_ (91) Pd_9-Fr and Ag_ (87) Pd_ (13) -Fr was 9.3 times and 5.4 times higher than Pd / C, 0.06 and 0.01 V lower on C. When the replacement time exceeds 2 h, the fine structure of the dendritic structure disappears, the voids between the whole structure become smaller, the specific surface area decreases, and the generation and coverage of AgCl precipitation on the surface are formed. Although the palladium content of the dendritic composite increases , But the electrocatalytic activity is low.