多壁碳纳米管负载铂立方体的制备及对乙醇电催化氧化性能

利用线性扫描电沉积的方法在玻碳电极或多壁碳纳米管表面制备出铂纳米立方体, 扫描电子显微镜(SEM)和透射电子显微镜(TEM)结果表明, 铂立方体的尺度约为38 nm, 由Pt(111)择优取向的小粒子围成. 运用电化学循环伏安和电位阶跃技术研究了所合成的2种催化剂和商用碳载铂对乙醇氧化的电催化活性, 发现在2种铂纳米立方体上乙醇氧化的电催化活性和稳定性均高于商用碳载铂, 其起峰电位较商业碳载铂降低168 mV. 采用电化学原位红外光谱对比研究了铂纳米立方体和商用碳载铂对乙醇氧化的电催化过程, 发现铂纳米立方体起始氧化电位提前, 催化活性增强. 乙醇在该催化剂上更易转化为乙酸, 且表现出较强的CO吸附能力.

Electrooxidation of Ethanol on Platinum Nanocubes Supported on Multi-walled Carbon Nanotubes

Platinum nanocubes deposited on glassy carbon(Ptcube/GC) or multi-walled carbon nanotubes(MWCNTs)(Ptcube/MWCNTs) were prepared with electrochemical deposition using linear sweep voltammetry. SEM and TEM results show that the average particle size of Ptcube/GC is 38 nm, which is composed of small particles surrounded by the Pt(111) preferred orientation. Electrochemical investigations including cyclic voltammetry and current-time curves, show that these two kinds of Pt cubes exhibit a higher catalytic activity and better stability for the oxidation of ethanol than commercial Pt/C. It is worth to note that Pt nanocubes show an onset potential shifted negatively by 168 mV than commercial Pt/C sample. Electrochemical in-situ FTIR spectroscopy was also used to study the adsorption and oxidation behavior of ethanol oxidation in acidic media on Ptcube/MWCNTs and commercial Pt/C. The results show that negative shift of oxidation potential and increase of catalytic activity on Ptcube/MWCNTs are mainly due to direct oxidation of ethanol to acetic acid at low potentials. In addition, the nanocubes also exhibit stronger CO adsorption.