Co-Pd-Sn和Cu-Pd-Si固溶體脫合金化制備納米多孔Pd及其電催化性能研究
發(fā)布時間：2018-10-22 10:05
【摘要】：納米多孔金屬材料的制備及其電催化性能的研究是近年來材料領域的熱門研究方向。固溶體合金是制備納米多孔金屬的良好前驅體合金材料,本文研究了Co-Pd-Sn和Cu-Pd-Si兩種系列的固溶體合金,通過電化學脫合金化的方法制備出納米多孔Pd合金,并利用X射線衍射儀(XRD),掃描/透射電子顯微鏡(SEM/TEM),能譜分析技術(EDX)和電化學分析等手段對納米多孔結構的形貌成分和電催化性能進行表征分析。研究工作主要包括以下內(nèi)容：(1)采用微合金化的思路,向Co-Pd二元固溶體合金中添加微量的Sn,通過熔體快淬的方法制備出Co79Pd20Sn1、Co80Pd19Sn1、Co80Pd19.5Sn0.5固溶體合金寬帶樣品,條帶寬度5mm左右,厚度約為60μm。XRD與TEM的分析表明,合金相組成是FCC的Co-Pd固溶體基體與一種金屬間化合物的析出相。在0.1M H2SO4溶液中對樣品進行電化學脫合金化,得到孔徑尺寸在5～20nm左右且結構形貌均勻的納米多孔Pd合金。脫合金化后的條帶樣品表面幾乎沒有裂紋,相比于Co80Pd20二元合金在脫合金化后的明顯開裂,添加Sn元素的固溶體合金強度和完整性有了明顯的改善與提高。(2)煉制了11種成分的Cu-Pd-Si系固溶體合金,利用熔體快淬制備出條帶樣品,在0.5M H2SO4溶液中分別進行動電位極化曲線掃描,結果表明,只有Cu75Pd20Si5、 Cu8oPd15Si5這兩種成分的合金的可實現(xiàn)電化學脫合金化,具有制備納米多孔Pd的條件。選擇適宜的條件進行脫合金化,在Cu75Pd20Si5合金中形成了三維貫通孔徑均勻的納米多孔Pd結構,孔徑大小5～10nm,而在Cu8oPdi5Si5合金中,多孔的形成不均勻且連通性不好。其中Si的加入使得FCC結構的Cu-Pd固溶體基體中有新的析出相Pd2Si,該析出相在固溶體基體中起到了強化基體的作用,防止合金在脫合金化后出現(xiàn)大面積的開裂。(3)對Co80Pd19Sn1和Cu75Pd20Si5兩種成分的前驅體合金經(jīng)脫合金化得到的納米多孔Pd分別進行電催化性能測試：在1M KOH和0.5M甲醇混合溶液中進行循環(huán)伏安(Cyclic Voltammetry)曲線掃描。實驗結果表明,制備的納米多孔Pd在堿性溶液中對甲醇的電氧化反應均表現(xiàn)出較好的催化活性和穩(wěn)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.
【學位授予單位】：大連理工大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：TB383.1;O643.36
本文編號：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.
【學位授予單位】：大連理工大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：TB383.1;O643.36
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