过渡金属氮化物载体对低温燃料电池Pt催化剂性能的影响研究

发布时间：2018-07-08 13:46

本文选题：过渡金属氮化物 + 催化剂载体　；参考：《广东工业大学》2015年硕士论文

【摘要】：低温燃料电池中,铂碳催化剂由于碳载体与负载的铂粒子结合不牢固,催化过程中两者无协同作用,且碳载体易被腐蚀,造成铂颗粒的迁移、脱落和团聚,严重缩短了燃料电池的使用寿命,所以开发具有高活性和高稳定性的新型铂基催化剂及研究其协同催化机理具有十分重要的意义。本文使用溶剂热/水热法-后氮化处理方法可控合成了三种过渡金属氮化物：氮化钛纳米管(TiN NTs)、氮化钼钛(Ti0.8Mo0.2N)和氮化钴钛(Ti0.9Co0.1 N)纳米颗粒,并将其作为铂基催化剂载体。通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、比表面积测试(BET)、X射线光电子能谱(XPS)和电化学方法对合成的催化剂的结构表征、电催化性能进行了研究。Pt/TiN NTs催化剂的氧还原性能测试结果表明,其具有高催化活性及稳定性。加速老化测试结果表明氮化钛纳米管载体可以提高催化剂的耐久性能,减少铂的电化学活性比表面积的损失。12000圈加速老化测试后,Pt/TiN NTs催化剂的电化学活性比表面积依然保持在77%,明显优于Pt/C (JM)催化剂。由于氮化钛纳米管粗糙的表面结构,可以重新捕获催化反应过程中溶解的铂颗粒,减少了铂的脱落及迁移,实验结果也证实了铂颗粒与氮化钛纳米管载体间有强相互作用。Pt/Ti0.8Mo0.2N催化剂的XRD和TEM测试结果说明了氮化钼钛是由单相晶体组成的,并且在甲醇氧化电催化测试中,氮化钼钛作为Pt催化剂载体对比Pt/C(JM)催化剂具有更高的质量比活性及耐久性。实验结果表明钼的掺杂是产生协同催化及电子效应的原因。Pt/Ti0.9Co0.1N催化剂在氧还原性能测试中表现出高催化活性和稳定性的特点。XRD和TEM测试结果表明氮化钴钛纳米颗粒是由高纯单相晶体组成。通过XPS测试可以看出铂颗粒与氮化钴钛载体间具有强相互作用。氧还原性能测试结果表明,对比Pt/C(JM)催化剂,Pt/Ti0.9Co0.1N催化剂具有更高的质量比活性和耐久性。经过10000圈的加速老化测试,Pt/Ti0.9Co0.1N催化剂依旧存在60%的电化学活性比表面积,远远高出Pt/C(JM)催化剂。实验结果表明,由于钴的掺杂,改变了铂的电子结构,使得铂颗粒与载体间的相互作用得到加强。
[Abstract]:In low temperature fuel cells, platinum / carbon catalyst has no synergistic effect due to the weak binding between carbon carrier and supported platinum particles, and the carbon carrier is easy to be corroded, resulting in the migration, falling off and agglomeration of platinum particles. Therefore, it is of great significance to develop a new platinum-based catalyst with high activity and stability and to study its synergistic mechanism. Three kinds of transition metal nitrides, titanium nitride nanotubes (tin NTs), molybdenum titanium nitride (Ti 0.8Mo 0.2N) and cobalt titanium nitride (Ti 0.9Co 0.1 N) nanoparticles were synthesized by solvothermal / hydrothermal method and post-nitridation treatment. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area measurement (BET), X-ray photoelectron spectroscopy (XPS) and electrochemical methods. The oxygen reduction performance of the catalyst. PT / tin NTs was studied. The results showed that the catalyst had high catalytic activity and stability. The results of accelerated aging test showed that the support of titanium nitride nanotubes could improve the durability of the catalyst. After accelerated aging test, the electrochemical activity specific surface area of Pt / tin NTs catalyst remained at 77%, which was obviously superior to that of PT / C (JM) catalyst. Due to the rough surface structure of titanium nitride nanotubes, platinum particles dissolved in the catalytic reaction can be recaptured, thus reducing the falling off and migration of platinum. The results also confirmed the strong interaction between platinum particles and titanium nitride nanotube support. The XRD and TEM results of Pt / Ti _ 0.8Mo _ (0.2N) catalyst showed that Mo-Ti nitride was composed of single phase crystal and was used in methanol oxidation electrocatalysis test. Compared with PT / C (JM) catalyst, Mo Ti nitride as Pt catalyst carrier has higher mass specific activity and durability than Pt- C (JM) catalyst. The results show that the doping of molybdenum is the cause of co-catalysis and electron effect. The catalytic activity and stability of Pt / Ti _ 0.9Co _ (0.1N) catalyst showed high catalytic activity and stability in oxygen reduction test. XRD and TEM results showed that cobalt and titanium nitride nanoparticles showed high catalytic activity and stability. Is composed of high-purity single-phase crystals. XPS results show that there is a strong interaction between platinum particles and cobalt-titanium nitride carriers. The results of oxygen reduction test showed that compared with Pt / Ti _ 0.9Co _ (0.1N) catalyst, Pt- / Ti _ (0.9) Co _ (0.1N) catalyst had higher mass specific activity and durability than that of PT / C (JM) catalyst. After 10000 cycles of accelerated aging test, the electrochemical activity specific surface area of PTR / Ti0.9Co0.1N catalyst is still 60%, which is much higher than that of PTR / C (JM) catalyst. The experimental results show that the electronic structure of platinum is changed due to cobalt doping and the interaction between platinum particles and support is strengthened.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM911.46;O643.36

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