摘要本论文以MoO2(acac)2为前驱体,采用不同管径的碳纳米管MHx为载体,利用浸渍+程序升温自碳化法分别制备了Pd/Mo2CMHx和Mo2C/PdMHx两个系列样品。通过对比发现采用先负载Mo2C后负载Pd的方案一获得的Pd/Mo2CMHx催化剂中Pd粒径较小(9.5nm),采用先负载Pd后负载Mo2C的方案二获得的Mo2C/PdMHx催化剂中Pd粒径较大(24.9nm)。
通过电化学循环伏安分析,在1MKOH和1M乙醇溶液体系中,对比Pd/Mo2CMHx系列催化剂对乙醇的电催化氧化电流发现,Pd/Mo2CMH8催化剂的循环伏安性能最佳,乙醇氧化峰值电流可达3.65mA;对比Mo2C/PdMHx系列催化剂对乙醇的电催化氧化电流发现,Mo2C/PdMH3催化剂的循环伏安性能最佳,乙醇氧化峰值电流可达13.75mA。尽管方案一获得的Pd/Mo2CMH3样品中Pd粒径较小,但方案二获得的Mo2C/PdMH3对乙醇的电催化氧化活性明显优于Pd/Mo2CMH3。
进一步通过线性扫描伏安、Tafel曲线分析,研究了Mo2C/PdMH3对乙醇的电催化氧化动力学发现,乙醇在Mo2C/PdMH3上的电催化氧化受pH值和乙醇浓度的影响,反应级数分别为0.7和0.5。6070
关键词:碳化钼;燃料电池;乙醇电氧化;Pd;碳纳米管
Abstract
In this work, two series of catalysts, Pd/Mo2CMHx and Mo2C/PdMHx, are synthesized by impregnation + the temperature-programmed self-carbonization method using MoO2(acac)2 as precursor, and multi-wall carbon nanotubes with different diameter (MHx) as support. Pd particle size of Pd/Mo2CMHx is around 9.5nm, which is much smaller than that of Mo2C/PdMHx (24.9nm)By comparing the load after load Mo2C first Pd is found that the scheme obtained a Pd/Mo2CMHx catalyst in Pd particle size smaller (9.5 nm), USES the load after load Pd first Mo2C scheme ii Mo2C/PdMHx obtained catalysts in Pd particle size is larger (24.9 nm).
According to cyclic voltammograms analysis in 1M KOH + 1M ethanol solution, the highest ethanol electooxidation peak current (3.65mA) is obtained on Pd/Mo2CMH8 catalyst in Pd/Mo2CMHx series catalysts; and in Mo2C/PdMHx series catalysts, the highest ethanol electooxidation peak current (13.75mA) is achieved on Mo2C/PdMH3 catalyst. Although the Pd particle size of Pd/Mo2CMH3 (9.5nm) is much smaller than that of Mo2C/PdMH3 (13.75nm), the ethanol electrooxidation catalytic activity on Mo2C/PdMH3 is much better than that on Pd/Mo2CMH3.
By linear sweep voltammograms and Tafel curve analysis, the kinetic of ethanol electrooxidation is influenced by pH and ethanol concentration. The reaction order of OH- and ethanol are 0.7 and 0.5, respectively.
Keywords:molybdenum carbide, fuel cell, ethanol electrooxidation, Pd, carbon nanotubes
目 录
1 绪论 1
1.1 背景 1
1.2 碳化钼Mo2C 1
1.3 直接醇类燃料电池及其原理 2
1.4 乙醇燃料电池阳极催化剂 3
1.4.1 乙醇阳极催化反应机理 3
1.5 阳极催化材料 4
1.5.1 Pt金属催化剂 4
1.5.2 Pd金属催化剂 4
1.5.3 Pd合金催化剂 5
1.5.4 Pd及金属氧化物催化剂 5
1.5.5 其他催化剂 6
1.6 催化剂的制备方法 6
1.6.1 浸渍法 6
1.6.2 微波化学法 7
1.7 催化剂载体 7
1.8 研究课题的内容及其方案 8
1.8.1 研究课题内容 8
1.8.2 研究课题方案 8
2 实验部分 9
2.1 实验样品与仪器 9
2.1.1 试剂与气体 9
2.1.2 仪器 9
2.2 实验步骤 9
2.2.1 制备Mo2CMHx 9 Mo2C饰Pd基催化剂的制备与性能:http://www.751com.cn/cailiao/lunwen_3415.html