PtRu／C和PtNi／C催化剂合成及其对甲醇氧化的电催化性能

Synthesis of PtRu/C and PtNi/C catalysts and their electrocatalytic performance for methanol electrooxidation

采用微波多元醇法合成PtRu/C和PtNi/C催化剂,利用透射电镜(TEM)和X-射线衍射仪(XRD)对催化剂的微观结构和形貌进行了表征.结果表明,在催化剂中PtRu和PtNi合金纳米粒子的平均粒径分别为2.7和3.0nm,粒径均匀,并高度均匀地分散在碳载体上.电化学测试结果表明,与Pt/C催化剂相比,PtRu/C和PtNi/C催化剂对甲醇的电化学氧化具有更低的起始电位和更稳定的极化电流,说明PtRu/C和PtNi/C催化剂对甲醇氧化具有更稳定的电催化性能和更好的抗CO中毒性能.这是由于合金催化剂中的Ru和Ni可以在较低的电位下与其表面吸附水形成含氧物种,使Pt表面吸附的CO等中间物氧化为CO2,避免了催化剂的CO中毒.

PtRu/C and PtNi/C catalysts were prepared by microwave-assistant polyol process, and their microstructure and morphology were characterized by transmission electron microscopy （TEM） and X-ray diffraction （XRD）. The results showed that the average diameters of PtRu and PtNi alloy nanoparticles in the catalysts are 2.7 nm and 3.0 nm respectively, and the alloy nanoparticles are homogeneous in size and highly dispersed on the carbon support. Compared with the Pt/C catalyst, the synthesized PtRu/C and Pt- Ni/C catalysts exhibit lower onset oxidation potential and more stable polarization current for methanol electrooxidation. The facts indicate that the PtRu/C and PtNi/C catalysts have more durable electrocatalytic performance for methanol oxidation and better resistance to CO-poisoning than Pt/C catalyst. Because the Ru and Ni metals in the alloys can form oxygen-containing species with their surface adsorbed water under low potential, the adsorbed intermediates such as CO on Pt metal surface can be oxidized to CO2 and the CO-poisoning of the catalysts is avoided.