多壁碳纳米管负载高分散Pt-Pr_xCe_(1-x)O_(2-δ)复合催化剂对甲醇的电催化氧化作用研究

Preparation and Characterization of Platinum Nano Particles Modified with Praseodymium and Cerium Mixed Oxide on MWCNT for Methanol Electro-Oxidation

通过反向化学共沉淀法制备了PrxCe1-xO2-δ稀土纳米复合氧化物作为助催化掺杂剂,将其包覆在多壁碳纳米管(MWCNTs)的表面作为催化剂复合载体,然后使用了柠檬酸盐-KBH4液相还原法制备了粒径分布均匀、性质稳定的Pt纳米溶胶,并沉积在上述载体中得到负载型Pt-PrxCe1-xO2-δ/CNT复合电催化剂,制备的催化剂中Pt载量为20%(质量分数)。使用XRD,SEM等手段对催化剂样品进行了物相形貌表征,使用循环伏安法对催化剂的电化学性能进行了测试。结果表明,经Pr,Ce纳米复合氧化物掺杂的催化剂比传统Pt/CNT催化剂具有更低的甲醇氧化电位和更好的耐中间产物毒化能力。

The Pt-PrxCe1-xO2-δ nano oxides were synthesized by the reverse-eopreeipitation method, loaded on MWCNT. The platinum nano hydro-sol was attained by potassium borohydride assisted with sodium citrate homogenously. The Pt-PrxCe1-xO2-δ/CNT nano composite was obtained finally. The scanning electron microscope and X-ray diffraction were used to characterize the morphology of the samples. The cyclic-voltammogram was measured for methanol oxidation. The mass fraction of all the samples was 20%. Due to the electro-chemical behavior of the obtained catalysts in methanol and sulfuric acid, the onset potential of Pt-PrxCe1-xO2-δ/CNT was lower than which of pure Pt/ CNT, which showed a tendency of methanol and its oxides species on Pt-PrxCe1-xO2-δ/CNT. It was higher for the ratio of current density in the forward scanning than which in the backward scanning, which indicated that the tolerance against carbon monoxide of Pt-PrxCe1-xO2-δ/CNT was better than the Pt/CNT without modification.