钯基催化剂的制备及甲醇电催化性能的研究

发布时间：2018-03-15 22:39

本文选题：直接甲醇燃料电池　切入点：Pd　出处：《齐齐哈尔大学》2017年硕士论文　论文类型：学位论文

【摘要】：在直接甲醇燃料电池(direct methanol fuel cellDMFC)中,催化剂对其催化性能起到了关键性作用,目前最常用的催化材料是铂(Pt)基催化剂,由于Pt的资源匮乏,价格昂贵且会在甲醇电氧化过程中生成中间产物CO等物质而中毒导致活性下降,且DMFC的成本较高,限制了其大规模的应用。本文以Pd为基础材料,复合了几种物质作催化剂材料,研究其对甲醇的电催化性能及电化学稳定性。本文制备了钯/石墨烯(Pd/RGO)、钯/聚二甲基二烯丙基氯化铵-石墨烯(Pd/PDDA-RGO)、钯/氧化镁-石墨烯(Pd/MgO-RGO)和钯/氧化镁-聚二甲基二烯丙基氯化铵-石墨烯(Pd/MgO-PDDA-RGO)四种催化剂,并利用透射电子显微镜(TEM)和X-射线衍射(XRD)对其进行表征,利用循环伏安法(CV)和计时电流法(CA)研究其对甲醇的电化学行为。正向阳极峰电流密度(If)/反向阳极峰电流密度(Ib)的值可反映甲醇的氧化率以及中间含碳物质的中毒耐受性。Pd/RGO、Pd/PDDA-RGO、Pd/MgO-RGO和Pd/MgO-PDDA-RGO的If/Ib值分别为1.57、1.68、2.87和3.23且If/Ib值依次增大,结果表明,Pd/MgO-PDDA-RGO表现出更高的电催化活性和更好的CO中毒耐受性。第n次循环正向阳极峰电流密度(In)/第一次循环正向阳极峰电流密度(I0)的值可评价催化剂的长期稳定性,在1000次循环之后,Pd/MgO-PDDA-RGO、Pd/MgO-RGO、Pd/PDDA-RGO和Pd/RGOIn/I0值分别为83%、78%、71%和69%且依次减小,结果表明,Pd/MgO-PDDA-RGO表现出更高的电催化性能以及更好的稳定性。本文制备了钯/石墨烯(Pd/RGO)和钯/乙二铵四乙酸-石墨烯(Pd/EDTA-RGO)两种催化剂,利用循环伏安法(CV)和计时电流(CA)研究其对甲醇的电化学行为。Pd/EDTA-RGOIf/Ib值是Pd/RGOIf/Ib值的1.08倍,表明Pd/EDTA-RGO表现出更高的电催化活性和更好的CO中毒耐受性。在1000次循环之后Pd/EDTA-RGOIn/I0值是79%高于Pd/RGO In/I0值的69%,结果表明,Pd/EDTA-RGO表现出更高的电催化性能以及更好的稳定性。比较Pd/MgO-PDDA-RGO和Pd/EDTA-RGO对甲醇的电催化性及稳定性,Pd/MgO-PDDA-RGO的If/Ib值是EDTA/Pd-RGO的If/Ib值的2.56倍,在1000次循环之后Pd/MgO-PDDA-RGO In/I0值为83%高于EDTA/Pd-RGO In/I0值的79%,表明Pd/MgO--PDDA-RGO对甲醇的电催化性更高且有更好的长期循环稳定性。
[Abstract]:In direct methanol fuel cell DMFCs, the catalyst plays a key role in its catalytic performance. At present, the most commonly used catalyst is platinum-based catalyst, due to the lack of Pt resources. Due to the high cost and poisoning of intermediate products such as CO in the process of methanol electrooxidation, the activity of DMFC is decreased, and the cost of DMFC is high, which limits its application on a large scale. In this paper, PD is used as the basic material. Several substances were used as catalyst materials, The electrocatalytic properties and electrochemical stability of palladium / graphene (PD / graphene), palladium / poly (dimethyldiallylammonium chloride) graphene (PD / PDDA-RGOO), palladium / magnesium oxide-graphene (PD / MgO-RGOO) and palladium / magnesium oxide (PD / MgO-RGOO) were prepared. Diallyl ammonium chloride-graphene (PD / MgO-PDDA-RGO) four kinds of catalysts, It was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical behavior of methanol was studied by cyclic voltammetry (CV) and chronoamperometric method (CACA). The values of forward anodic peak current density / reverse anodic peak current density can reflect the oxidation rate of methanol and the poisoning of middle carbonaceous substance. The If/Ib values of PD / PDDA-RGON PD / RGOO / PD / MgO-RGO and Pd/MgO-PDDA-RGO were 1.57 / 1.682.87 and 3.23, respectively, and the If/Ib values increased in turn. The results show that PD / MgO-PDDA-RGO exhibits higher electrocatalytic activity and better tolerance to CO poisoning. The value of the nth cycle forward anode peak current density / the first cycle forward anode peak current density (I _ 0) can be used to evaluate the long-term stability of the catalyst. After 1, 000 cycles, the PD / MgO-PDDA-RGON / PD / MgO-RGOG / PD / PDDA-RGO and Pd/RGOIn/I0 values were 83% and 69%, respectively, and decreased in turn. The results show that PD / MgO-PDDA-RGO has higher electrocatalytic performance and better stability. In this paper, palladium / graphene (PD / RGO) and palladium / diammonium tetraacetic acid-graphene (PD / EDTA-RGO) catalysts were prepared. Cyclic voltammetry (CV) and chronoelectric current (CAA) were used to study the electrochemical behavior of methanol. The value of PD / EDTA-RGOIf / Ib was 1.08 times that of Pd/RGOIf/Ib. The results showed that Pd/EDTA-RGO showed higher electrocatalytic activity and better tolerance to CO poisoning. After 1 000 cycles, the Pd/EDTA-RGOIn/I0 value was 79% higher than that of Pd/RGO In/I0. The results showed that PD / EDTA-RGO showed higher electrocatalytic activity and better stability. The electrocatalytic activity and stability of Pd/MgO-PDDA-RGO and Pd/EDTA-RGO to methanol were 2.56 times of the If/Ib value of EDTA/Pd-RGO, and the If/Ib value of PD / MgO-PDDA-RGO was 2.56 times higher than that of EDTA/Pd-RGO. After 1 000 cycles, the Pd/MgO-PDDA-RGO In/I0 value of 83% is higher than that of EDTA/Pd-RGO In/I0, which indicates that Pd/MgO--PDDA-RGO has higher electrocatalysis and better long-term cycle stability for methanol.
【学位授予单位】：齐齐哈尔大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ426;TM911.4

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