Co-Pd-Sn和Cu-Pd-Si固溶体脱合金化制备纳米多孔Pd及其电催化性能研究
发布时间：2018-10-22 10:05
【摘要】：纳米多孔金属材料的制备及其电催化性能的研究是近年来材料领域的热门研究方向。固溶体合金是制备纳米多孔金属的良好前驱体合金材料,本文研究了Co-Pd-Sn和Cu-Pd-Si两种系列的固溶体合金,通过电化学脱合金化的方法制备出纳米多孔Pd合金,并利用X射线衍射仪(XRD),扫描/透射电子显微镜(SEM/TEM),能谱分析技术(EDX)和电化学分析等手段对纳米多孔结构的形貌成分和电催化性能进行表征分析。研究工作主要包括以下内容：(1)采用微合金化的思路,向Co-Pd二元固溶体合金中添加微量的Sn,通过熔体快淬的方法制备出Co79Pd20Sn1、Co80Pd19Sn1、Co80Pd19.5Sn0.5固溶体合金宽带样品,条带宽度5mm左右,厚度约为60μm。XRD与TEM的分析表明,合金相组成是FCC的Co-Pd固溶体基体与一种金属间化合物的析出相。在0.1M H2SO4溶液中对样品进行电化学脱合金化,得到孔径尺寸在5～20nm左右且结构形貌均匀的纳米多孔Pd合金。脱合金化后的条带样品表面几乎没有裂纹,相比于Co80Pd20二元合金在脱合金化后的明显开裂,添加Sn元素的固溶体合金强度和完整性有了明显的改善与提高。(2)炼制了11种成分的Cu-Pd-Si系固溶体合金,利用熔体快淬制备出条带样品,在0.5M H2SO4溶液中分别进行动电位极化曲线扫描,结果表明,只有Cu75Pd20Si5、 Cu8oPd15Si5这两种成分的合金的可实现电化学脱合金化,具有制备纳米多孔Pd的条件。选择适宜的条件进行脱合金化,在Cu75Pd20Si5合金中形成了三维贯通孔径均匀的纳米多孔Pd结构,孔径大小5～10nm,而在Cu8oPdi5Si5合金中,多孔的形成不均匀且连通性不好。其中Si的加入使得FCC结构的Cu-Pd固溶体基体中有新的析出相Pd2Si,该析出相在固溶体基体中起到了强化基体的作用,防止合金在脱合金化后出现大面积的开裂。(3)对Co80Pd19Sn1和Cu75Pd20Si5两种成分的前驱体合金经脱合金化得到的纳米多孔Pd分别进行电催化性能测试：在1M KOH和0.5M甲醇混合溶液中进行循环伏安(Cyclic Voltammetry)曲线扫描。实验结果表明,制备的纳米多孔Pd在碱性溶液中对甲醇的电氧化反应均表现出较好的催化活性和稳定性。
[Abstract]:The preparation of nano-porous metal materials and their electrocatalytic properties are the hot research directions in the field of materials in recent years. The solid solution alloy is a good precursor material for the preparation of nano-porous metal. In this paper, two series of solid solution alloys, Co-Pd-Sn and Cu-Pd-Si, were prepared by electrochemical de-alloying. X-ray diffractometer (XRD),) scanning / transmission electron microscopy (SEM/TEM), energy dispersive spectroscopy (EDX) and electrochemical analysis were used to characterize the morphology and electrocatalytic properties of the porous nanostructures. The main contents of the research are as follows: (1) by using the idea of microalloying, adding a small amount of Sn, to Co-Pd binary solid solution alloy, a wide band of Co79Pd20Sn1,Co80Pd19Sn1,Co80Pd19.5Sn0.5 solid solution alloy samples were prepared by melt rapid quenching. The band width of Co79Pd20Sn1,Co80Pd19Sn1,Co80Pd19.5Sn0.5 solid solution alloy was about 5mm. The analysis of thickness about 60 渭 m.XRD and TEM shows that the phase composition of the alloy is the precipitated phase of the Co-Pd solid solution matrix of FCC and an intermetallic compound. The nano-porous Pd alloy with pore size about 5~20nm and uniform structure was obtained by electrochemical de-alloying in 0.1M H2SO4 solution. There was almost no crack on the surface of the strip after dealloying, which was obviously different from that of Co80Pd20 binary alloy after dealloying. The strength and integrity of the solid solution alloy with the addition of Sn elements have been obviously improved and improved. (2) 11 kinds of Cu-Pd-Si system solid solution alloys were refined, and the strip samples were prepared by melt rapid quenching. The potentiodynamic polarization curves were scanned in 0.5m H2SO4 solution. The results showed that only the alloys with two components of Cu75Pd20Si5, Cu8oPd15Si5 could be dealloyed by electrochemical method, and the conditions for the preparation of nano-porous Pd were obtained. When suitable conditions were chosen for dealloying, a three-dimensional porous Pd structure with uniform perforated pore size was formed in Cu75Pd20Si5 alloy, and the pore size was 510nm, while in Cu8oPdi5Si5 alloy, the formation of pores was not uniform and the connectivity was not good. With the addition of Si, there is a new precipitated phase Pd2Si, in the Cu-Pd solid solution matrix of FCC structure, which plays the role of strengthening the matrix in the solid solution matrix. (3) the electrocatalytic properties of Co80Pd19Sn1 and Cu75Pd20Si5 precursor alloys obtained by dealloying nano-porous Pd were tested in 1m KOH and 0.5M methanol mixed solution respectively. (3) to prevent the alloy from cracking in large area after dealloying. (3) the electrocatalytic properties of nano-porous Pd obtained from the dealloying of Co80Pd19Sn1 and Cu75Pd20Si5 were tested respectively in the mixture of 1 M KOH and 0.5 M methanol. The cyclic voltammetry (Cyclic Voltammetry) curves were scanned. The experimental results showed that the prepared nano-porous Pd exhibited good catalytic activity and stability for methanol electrooxidation in alkaline solution.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB383.1;O643.36
本文编号：2286864
[Abstract]:The preparation of nano-porous metal materials and their electrocatalytic properties are the hot research directions in the field of materials in recent years. The solid solution alloy is a good precursor material for the preparation of nano-porous metal. In this paper, two series of solid solution alloys, Co-Pd-Sn and Cu-Pd-Si, were prepared by electrochemical de-alloying. X-ray diffractometer (XRD),) scanning / transmission electron microscopy (SEM/TEM), energy dispersive spectroscopy (EDX) and electrochemical analysis were used to characterize the morphology and electrocatalytic properties of the porous nanostructures. The main contents of the research are as follows: (1) by using the idea of microalloying, adding a small amount of Sn, to Co-Pd binary solid solution alloy, a wide band of Co79Pd20Sn1,Co80Pd19Sn1,Co80Pd19.5Sn0.5 solid solution alloy samples were prepared by melt rapid quenching. The band width of Co79Pd20Sn1,Co80Pd19Sn1,Co80Pd19.5Sn0.5 solid solution alloy was about 5mm. The analysis of thickness about 60 渭 m.XRD and TEM shows that the phase composition of the alloy is the precipitated phase of the Co-Pd solid solution matrix of FCC and an intermetallic compound. The nano-porous Pd alloy with pore size about 5~20nm and uniform structure was obtained by electrochemical de-alloying in 0.1M H2SO4 solution. There was almost no crack on the surface of the strip after dealloying, which was obviously different from that of Co80Pd20 binary alloy after dealloying. The strength and integrity of the solid solution alloy with the addition of Sn elements have been obviously improved and improved. (2) 11 kinds of Cu-Pd-Si system solid solution alloys were refined, and the strip samples were prepared by melt rapid quenching. The potentiodynamic polarization curves were scanned in 0.5m H2SO4 solution. The results showed that only the alloys with two components of Cu75Pd20Si5, Cu8oPd15Si5 could be dealloyed by electrochemical method, and the conditions for the preparation of nano-porous Pd were obtained. When suitable conditions were chosen for dealloying, a three-dimensional porous Pd structure with uniform perforated pore size was formed in Cu75Pd20Si5 alloy, and the pore size was 510nm, while in Cu8oPdi5Si5 alloy, the formation of pores was not uniform and the connectivity was not good. With the addition of Si, there is a new precipitated phase Pd2Si, in the Cu-Pd solid solution matrix of FCC structure, which plays the role of strengthening the matrix in the solid solution matrix. (3) the electrocatalytic properties of Co80Pd19Sn1 and Cu75Pd20Si5 precursor alloys obtained by dealloying nano-porous Pd were tested in 1m KOH and 0.5M methanol mixed solution respectively. (3) to prevent the alloy from cracking in large area after dealloying. (3) the electrocatalytic properties of nano-porous Pd obtained from the dealloying of Co80Pd19Sn1 and Cu75Pd20Si5 were tested respectively in the mixture of 1 M KOH and 0.5 M methanol. The cyclic voltammetry (Cyclic Voltammetry) curves were scanned. The experimental results showed that the prepared nano-porous Pd exhibited good catalytic activity and stability for methanol electrooxidation in alkaline solution.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB383.1;O643.36
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